JP2000171840A - Laminated thin-film optical element and optical control method and optical controller using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to exhibit optical response of sufficient magnitude and high speed by using a laser beam of low power as control light. SOLUTION: The control light is emitted from a light source 1 and signal light from a light source 2. The control light and the signal light are converged by a condenser lens 7 and is cast to the laminated thin-film optical element 8. Only the signal light is detected by a photodetector 22 through a photodetecting lens 9 and a wavelength selection filter 20. A heat lens is reversibly formed within the laminated thin-film optical element by on and off of the control light, by which the intensity modulation of the signal light may be embodied. The constitution of the thin-film optical element is composed of a laminated structure consisting of for example, a heat transmission layer film/heat insulating layer film/light absorption film/heat lens forming layer/light absorption film/heat insulating layer film/heat transmission layer. The thickness of the light absorption layer consisting of the laminated structure of the light absorption film/heat lens forming layer/light absorption film is so adjusted as not to exceed 2 times the confocal distance of the converged control light.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated thin-film optical element, and a light control method and a light control apparatus using the same, which are useful in the fields of optoelectronics and photonics such as optical communication and optical information processing. .

[0002]

2. Description of the Related Art In the field of optoelectronics and photonics, which focus on the multiplexing and high density of light for the purpose of transmitting and processing information at an ultra-high speed, light is applied to an optical element prepared by processing an optical material or an optical composition. Of light / light control method that modulates light intensity (amplitude) or frequency (wavelength) without using electronic circuit technology, using changes in transmittance and refractive index caused by irradiating light Development is underway. Also, taking advantage of the characteristics of light,
When parallel optical logic operation or image processing is to be performed, a "spatial light modulator" for performing any kind of modulation such as a change in light intensity distribution on the cross section of a light beam is extremely important. Application of the control method is expected.

As phenomena that are expected to be applied to light / light control methods, saturable absorption, nonlinear refraction, nonlinear optical effects such as photorefractive effects, and photochromic phenomena have attracted widespread attention.

[0004] On the other hand, there is a phenomenon that molecules excited by light in the first wavelength band newly absorb light in a second wavelength band different from the first wavelength band without changing the molecular structure. It is known and can be referred to as "excited state absorption" or "induced absorption" or "transient absorption".

[0005] Examples of applications of excited state absorption include:
For example, JP-A-53-137883 discloses that a solution or a solid containing a porphyrin compound and an electron acceptor is irradiated with at least two types of light beams having different wavelengths, and the irradiation causes a light beam having one wavelength to be emitted. A light conversion method is disclosed that transfers information to the wavelength of the other light beam. Also, JP-A-55-100503 and JP-A-55-150503
Japanese Patent Application Laid-Open No. 108603/1993 discloses a method of selecting a propagating light in response to a temporal change of excitation light by utilizing a difference in a spectrum between a ground state and an excited state of an organic compound such as a porphyrin derivative. A liquid core optical fiber is disclosed. JP-A-61-129621 discloses that a first photon flux is introduced into a fiber made of barium crown glass doped with uranium oxide so that the first photon flux is not attenuated and a second photon flux is introduced. Attenuates the bundle and energy level of the fiber 2
And a part of the first photon flux is absorbed to populate the energy level 3 and the energy level 3
Is returned to energy level 2 again to further attenuate the first photon flux. JP-A-63-89805 discloses that a core contains an organic compound such as a porphyrin derivative having an absorption corresponding to a transition from a triplet state excited by light to a higher triplet state. A plastic optical fiber is disclosed. Japanese Unexamined Patent Publication (Kokai) No. 63-236013 discloses that a crystal of a cyanine dye such as cryptocyanine is irradiated with light of a first wavelength to optically excite molecules, and then a light of a second wavelength different from the first wavelength. An optical functional element that irradiates the molecule with light and switches transmission or reflection of light of a second wavelength according to a photoexcitation state by light of a first wavelength is disclosed. JP-A-64-73326 discloses that a light modulation medium in which a photoinduced electron transfer material such as a porphyrin derivative is dispersed in a matrix material is irradiated with light of first and second wavelengths to excite the excited state of the molecule. An optical signal modulation medium that modulates light using a difference in absorption spectrum between the light and the ground state is disclosed.

The configurations of the optical devices used in these prior arts are described in JP-A-55-100503, JP-A-55-108603, and JP-A-63-8.
Japanese Patent Application Laid-Open No. 9805 discloses a device configuration in which an optical fiber through which a propagating light propagates is wound around a light source of an excitation light (for example, a flash lamp).
Japanese Patent No. 37884 and Japanese Patent Application Laid-Open No. 64-73326 disclose control light from a direction different from the optical path of the signal light over the entire propagation portion of the light corresponding to the signal light inside the photoresponsive optical element. There is disclosed an apparatus configuration in which light is not converged but rather diffused and irradiated by means such as a projection lens.

Further, in the prior art, a method of modulating light using a refractive index distribution due to a thermal effect has been studied. JP-A-59-68723 discloses that, according to a refractive index distribution in a liquid medium, an input electric signal is supplied to a heating resistor and a refractive index distribution is generated by receiving heat from the heating means.
There is disclosed a light modulation element that deforms the wavefront of a light beam, and describes that a cycle from formation of a refractive index distribution to extinction can be performed on the order of KHz, that is, on the order of milliseconds. Also, Japanese Patent Application Laid-Open No. Sho 60-130723
In the publication, near-infrared control light is converted into heat energy in a heat absorption layer, and this heat is transferred to the heat effect medium through the near-infrared reflection film layer and the visible light reflection film layer, and is generated in the heat effect medium. A method is disclosed in which the wavefront of a light beam incident on a visible light reflecting film layer is converted according to the refractive index distribution.

[0008]

However, the above-described method of modulating light using the refractive index distribution by the thermal effect requires a long heat transmission path until the thermal effect is generated, and
Since the area of the temperature rising portion is transmitted while being enlarged compared to the control light beam cross-sectional area, the volume of the transmission path, that is, the heat capacity is increased, and the utilization efficiency of the energy given from the control light is low, and a high-speed response can be expected. Absent.

Further, any of the above-mentioned prior arts causes a change in transmittance or a change in the refractive index of a size sufficient for practical use, so that a very high-density optical power is required, a response to light irradiation is slow, Since fine control of the optical system is required, and the control light output greatly fluctuates due to slight fluctuations of the optical system, there is no practical application yet.

For the purpose of solving the above-mentioned problems and extracting an optical response of a sufficient magnitude and speed with an optical power as low as possible, Japanese Patent Application Laid-Open Nos. 8-286220 and 8-32053 are disclosed.
5, 8-320536, 9-329816, 10-90
733, 10-90734, and 10-14885
In the second report, the control element is irradiated with an optical element made of a photoresponsive composition, and the transmittance and / or the refractive index of the signal light in a wavelength band different from that of the control light are reversibly changed. A light control method for performing intensity modulation and / or light flux density modulation of the signal light transmitted through an optical element, wherein the control light and the signal light are respectively converged and irradiated to the optical element, and the control light is controlled. And an optical path for the control light and the signal light, wherein the optical paths of the control light and the signal light are arranged such that regions having the highest photon densities near respective focal points of the signal light overlap each other in the optical element. Have been.

Japanese Patent Application Laid-Open No. H10-148853 discloses that an optical element made of a photoresponsive composition is irradiated with control light and signal light having different wavelengths from each other, and the wavelength of the control light is different from that of the photoresponsive composition. The thermal lens based on the distribution of the density change caused by the temperature rise occurring in the region where the photoresponsive composition absorbs the control light and in the surrounding region, and the heat lens is reversibly selected. And intensity modulation of signal light transmitted through the thermal lens and / or
Alternatively, a light control method for performing light flux density modulation is disclosed. In the above publication, for example, a dye / resin film or a dye solution film is used as an optical element, and the response time of signal light to control light irradiation at a power of 2 to 25 mW of control light is described as less than 2 microseconds. .

The present invention solves the above-mentioned problems, and provides a laminated thin-film optical element capable of extracting an optical response of a sufficient size and a higher speed with an optical power as low as possible, and a light control method and a control apparatus using the same. The purpose is to provide.

[0013]

In order to achieve the above object, a laminated thin film optical device according to the present invention according to claim 1 of the present application comprises a light absorbing layer in a laminated thin film optical device including at least a light absorbing layer. The control light and the signal light having different wavelengths are respectively converged and irradiated, and the wavelength of the control light is selected from a wavelength band absorbed by the light absorbing layer, and at least the control light is focused in the light absorbing layer. By using a thermal lens based on a refractive index distribution that is reversibly generated due to a temperature rise that occurs in the region where the light absorbing layer absorbs the control light and the surrounding region, the intensity of the signal light is reduced. In the thin-film optical element for performing modulation and / or light flux density modulation, the light absorption layer is a laminated thin film including three layers, and the first layer is a light absorption film that absorbs light in the wavelength band of the control light. Yes, second Is a thermal lens forming layer that is light transmissive in the wavelength band of the control light and the signal light, and the third layer is a light absorbing film that absorbs light in the wavelength band of the control light. I do.

Here, it is assumed that the signal light and the control light are substantially perpendicularly incident on the laminated thin film optical element in order to minimize the loss due to reflection.

According to a second aspect of the present invention, there is provided a laminated thin-film optical element according to the first aspect of the present invention. Of the light absorbing films, the light absorbing film on the control light incident side absorbs 10 to 90% of the control light, and the light absorbing film on the control light emitting side removes the remaining control light. The transmittance of the control light wavelength band is adjusted so as to be absorbed.

In order to achieve the above object, the laminated thin-film optical element according to the third and fourth aspects of the present invention is characterized in that in the laminated thin-film optical element according to the first and second aspects, The thickness of the light-absorbing layer composed of the laminated thin film does not exceed twice the confocal distance of the converged control light.

Here, the confocal distance is a distance of a section where a light beam converged by a converging means such as a convex lens or a gradient index lens can be regarded as substantially parallel light near a beam waist (focal point). . In the case of a Gaussian beam in which the amplitude distribution of the electric field in the beam section in the traveling direction, that is, the energy distribution of the light beam is a Gaussian distribution, the confocal distance Zc is calculated by using a circular constant π, a beam waist radius ω ₀ and a wavelength λ. It can be expressed by (1).

[0018]

Zc = πω ₀ ² / λ (1) The lower limit of the thickness of the light absorbing layer is preferably as thin as possible so long as the optical response can be detected.

According to a fifth aspect of the present invention, there is provided a laminated thin-film optical element according to any one of the first to fourth aspects. Further comprising a heat-insulating layer film that is light-transmissive in the wavelength band of the control light and the signal light, and / or a heat-transfer layer that is light-transmissive in the wavelength band of the control light and the signal light. The membrane was prepared by the following group (a)
Or (i).

(A) light absorption layer / heat insulation layer film, (b) heat insulation layer film / light absorption layer / heat insulation layer film, (c) light absorption layer / heat transfer layer film, (d) heat transfer layer film / light Absorption layer / heat transfer layer film, (e) light absorption layer / heat insulation layer film / heat transfer layer film, (f) heat transfer layer film / light absorption layer / heat insulation layer film, (g) heat transfer layer film / light absorption (H) heat transfer layer film / heat insulation layer film / light absorption layer / heat insulation layer film, (i) heat transfer layer film / heat insulation layer film / light absorption layer / heat insulation layer film / Heat transfer layer film.

According to a sixth aspect of the present invention, there is provided a multilayer thin-film optical element according to the present invention, wherein the control light and the signal A refractive index distribution type lens as light converging means is laminated on the light absorbing layer on the signal light incident side, or a heat insulating layer film, or a heat transfer layer film, directly or further through a light transmitting layer. It is characterized by being provided.

According to a seventh aspect of the present invention, there is provided a laminated thin-film optical element according to any one of the first to fifth aspects of the present invention. The signal light flux that diverges after being transmitted through is extracted in an angle range smaller than the divergence angle of the signal light flux so that the signal light flux in an area that has been strongly subjected to intensity modulation and / or light flux density modulation. The refractive index distribution type lens as a means for separating and taking out the light absorption layer on the signal light emission side, or a heat insulation layer film, or a heat transfer layer film, directly or further through a light transmission layer, It is characterized by being provided in a stacked manner.

In order to achieve the above object, a laminated thin-film optical element according to the invention of claim 8 of the present application is the laminated thin-film optical element according to claim 6, wherein The signal light flux that diverges after being transmitted through is extracted in an angle range smaller than the divergence angle of the signal light flux so that the signal light flux in an area that has been strongly subjected to intensity modulation and / or light flux density modulation. The refractive index distribution type lens as a means for separating and taking out the light absorption layer on the signal light emission side, or a heat insulation layer film, or a heat transfer layer film, directly or further through a light transmission layer, The light absorbing layer is provided so as to face a gradient index lens provided on the signal light incident side of the light absorbing layer and to be stacked with their respective lens central axes aligned.

According to a ninth aspect of the present invention, there is provided a multilayer thin-film optical element according to any one of the first to fourth aspects, wherein the light-absorbing film is provided. Contains a dye that absorbs light in the control light wavelength band.

In order to achieve the above object, a laminated thin-film optical element according to the present invention as set forth in claim 10 of the present application is the laminated-type thin-film optical element according to any one of claims 1 to 4,
The light absorbing film is made of an amorphous aggregate of a dye that absorbs light in the control light wavelength band.

In order to achieve the above object, a laminated thin-film optical element according to the invention of claim 11 of the present application is characterized in that in the laminated thin-film optical element according to any one of claims 1 to 4,
The light-absorbing film is made of a fine crystal aggregate of a dye that absorbs light in the control light wavelength band, and the particle diameter of the dye fine crystal is shorter than the wavelength of the signal light and the wavelength of the control light. Is not larger than one-fifth of the wavelength.

In order to achieve the above object, a laminated thin-film optical element according to the invention of claim 12 of the present application is characterized in that in the laminated thin-film optical element according to any one of claims 1 to 4,
The thermal lens forming layer is made of an organic compound selected from the group consisting of an amorphous organic compound, an organic compound liquid, and a liquid crystal.

In order to achieve the above object, the light control method according to the invention of claim 13 of the present application provides the light control method according to claims 1 to 4
In the laminated thin film optical element according to any one of the above, the light absorbing layer is irradiated with converging control light and signal light having different wavelengths from each other, and the wavelength of the control light is a wavelength absorbed by the light absorbing layer. Selected from a band, at least the control light is focused in the light absorbing layer, and the light absorbing layer has a refractive index that reversibly occurs due to a temperature rise occurring in a region absorbing the control light and a peripheral region thereof. The intensity modulation and / or the luminous flux density modulation of the signal light is performed by using a thermal lens based on the distribution.

In order to achieve the above object, the light control method according to the present invention according to claims 14, 15 and 16 of the present invention provides the light control method according to claims 6, 7 and 8, respectively. In the type thin film optical element, the control light and the signal light are irradiated on the refractive index distribution type lens provided on the control light and the signal light incident side, respectively, and at least the control light is in the light absorption layer. Focusing, by using a thermal lens based on the refractive index distribution that reversibly occurs due to the temperature rise that occurs in the region where the light absorbing layer absorbs the control light and the surrounding region, the signal light of the It is characterized by performing intensity modulation and / or light flux density modulation.

In order to achieve the above object, a light control method according to the invention of claims 17 and 18 of the present application provides:
15. The light control method according to claim 13, wherein the signal light beam diverging after passing through the laminated thin film optical element has an angle range smaller than the divergence angle of the signal light beam. By extracting the signal light beam in the region that has been strongly subjected to intensity modulation and / or light flux density modulation, the signal light beam is separated and extracted.

In order to achieve the above object, a light control method according to the present invention as set forth in claims 19 and 20 of the present application,
In the light control methods according to claim 15 and claim 16, respectively, the light is transmitted through the light absorption layer using the refractive index distribution type lens laminated and provided on the signal light emission side of the light absorption layer. Later, the diverging signal light flux
By extracting the signal light beam in an angle range smaller than the divergence angle of the signal light beam, the signal light beam in a region that has been strongly subjected to intensity modulation and / or light beam density modulation is separated and extracted.

In order to achieve the above object, a light control device according to a twenty-first aspect of the present invention provides the laminated thin-film optical element according to any one of the first to fourth aspects, wherein the light absorption layer comprises: The control light and the signal light having different wavelengths are irradiated with each other, and the wavelength of the control light is selected from a wavelength band absorbed by the light absorption layer, and the light absorption layer is formed in a region where the control light is absorbed and a peripheral region thereof. An optical control device that performs intensity modulation and / or light flux density modulation of the signal light by using a thermal lens based on a refractive index distribution that is reversibly generated due to a rise in temperature, wherein the control light and the light Having converging means for converging the signal light respectively, so that the highest areas of the photon density near the respective focal points of the converged control light and the signal light overlap each other,
The optical paths of the control light and the signal light are respectively arranged, and the light absorption layer of the stacked thin film optical element has the highest photon density near the focal point of each of the converged control light and the signal light. The regions are arranged at positions overlapping each other.

In order to achieve the above object, according to a twenty-second aspect of the present invention, there is provided a light control device provided on the control light and signal light incident side in the stacked thin film optical element according to the sixth invention. The refractive index distribution type lens is irradiated with the control light and the signal light, respectively, at least the control light is focused in the light absorbing layer, the region where the light absorbing layer has absorbed the control light and A light control device that performs intensity modulation and / or light flux density modulation of the signal light by using a thermal lens based on a refractive index distribution reversibly generated due to a temperature rise occurring in a peripheral region thereof, The control light and the signal light having the refractive index distribution type lens provided on the signal light incident side as converging means for converging the control light and the signal light, respectively. The optical paths of the control light and the signal light are respectively arranged such that regions having the highest photon densities near the respective focal points of the signal light overlap with each other, and the light absorption layer of the thin film optical element is converged. A region having the highest photon density near the focal point of each of the control light and the signal light is arranged at a position where the regions overlap each other.

In order to achieve the above object, a light control device according to the present invention as defined in claims 23 and 24 of the present application comprises:
23. The light control device according to claim 21 or claim 22, wherein the signal light transmitted through the thin-film optical element is used as a means for separating and extracting a signal light beam in a region that has been strongly subjected to intensity modulation and / or light beam density modulation. Thereafter, there is provided means for extracting the diverging signal light beam within an angle range smaller than the divergence angle of the signal light beam.

In order to achieve the above object, a light control device according to the invention of claim 25 of the present application is the light control device according to claim 7, wherein the light absorption layers have different wavelengths from each other. Light and signal light, respectively, and the wavelength of the control light is selected from a wavelength band absorbed by the light absorbing layer, and the light absorbing layer is caused by a temperature rise occurring in a region where the control light is absorbed and a peripheral region thereof. By using a thermal lens based on the reversible refractive index distribution,
An optical control device for performing intensity modulation and / or luminous flux density modulation of the signal light, comprising converging means for converging the control light and the signal light, respectively, wherein each of the converged control light and the signal light is The optical paths of the control light and the signal light are respectively arranged so that the regions having the highest photon densities near the focal point of each other overlap with each other, and the light absorption layer of the stacked thin-film optical element includes the converged control. The regions having the highest photon densities in the vicinity of the respective focal points of the light and the signal light are arranged at positions overlapping each other, and further, the signal light beam that diverges after passing through the light absorbing layer is converted into the signal light beam. A means for separating and extracting a signal light beam in an area that has been strongly subjected to intensity modulation and / or light beam density modulation by extracting light in an angle range smaller than the divergence angle of the light beam. , And having the gradient index lens provided on the signal light output side of the light absorbing layer.

In order to achieve the above object, a light control device according to the invention of claim 26 of the present application is the light control device according to claim 8, which is provided on the incident side of the control light and the signal light. The refractive index distribution type lens is irradiated with the control light and the signal light, respectively, at least the control light is focused in the light absorbing layer, the region where the light absorbing layer has absorbed the control light and A light control device that performs intensity modulation and / or light flux density modulation of the signal light by using a thermal lens based on a refractive index distribution reversibly generated due to a temperature rise occurring in a peripheral region thereof, The control light and the signal light having the refractive index distribution type lens provided on the signal light incident side as converging means for converging the control light and the signal light, respectively. The optical paths of the control light and the signal light are respectively arranged such that regions having the highest photon densities in the vicinity of the respective focal points of the signal light overlap with each other. The regions having the highest photon densities in the vicinity of the respective focal points of the control light and the signal light are arranged at positions overlapping each other, and further, the signal light flux diverging after passing through the laminated thin film optical element As a means for separating and extracting a signal light beam in an area which has been strongly subjected to intensity modulation and / or light beam density modulation by extracting the signal light beam in an angle range smaller than the divergence angle of the signal light beam. And the refractive index distribution type lens provided on the signal light emission side.

[0037]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [Structure of laminated thin-film optical element] The thin-film optical element of the present invention has a laminated film-type structure.

(1) Light absorbing layer alone. However, in the present invention, the light-absorbing layer is composed of a laminated thin film having a three-layer structure of “light-absorbing film / thermal lens forming layer / light-absorbing film”. 3) Heat insulation layer / light absorption layer / heat insulation layer film (4) Light absorption layer / heat transfer layer film (5) Heat transfer layer film / light absorption layer / heat transfer layer film (6) Light absorption layer / heat insulation layer film / Heat transfer layer film (7) heat transfer layer film / light absorption layer / heat insulation layer film (8) heat transfer layer film / light absorption layer / heat insulation layer film / heat transfer layer film (9) heat transfer layer film / heat insulation layer (10) heat transfer layer film / heat insulation layer film / light absorption layer / heat insulation layer film / heat transfer layer film (11) refractive index distribution type lens / (light transmission layer /) (1) Laminated thin film optical element of (10) (12) Gradient index lens / (light transmission layer /) Laminated thin film optical element of (1) to (10) / (light transmission layer /) refractive index Distributed lens Serial to as "(light transmitting layer /)" means that the provision of the light transmission layer as needed. Further, if necessary, an antireflection film (AR coating film) may be provided on the light incident surface and the light exit surface.

FIG. 1 is a cross-sectional view illustrating the configuration of a laminated thin-film optical element according to the present invention. As illustrated in FIG. 1, the laminated thin-film optical element includes, for example, a gradient index lens 70 / a light transmitting layer 82 / a light from the incident side of the control light S1 and the signal light S2.
The heat insulating layer 83 / the light absorbing film 84 / the thermal lens forming layer 80 / the light absorbing film 85 / the heat transfer layer 86 / the light transmitting layer 89 / the refractive index distribution type lens 90 are laminated in this order.

The light absorbing film, the thermal lens forming layer, the heat insulating layer film, the heat transfer layer film, the light transmitting layer, and the material of the gradient index lens,
The preparation method, the thickness of each film, and the like will be described below step by step.

The materials of the light absorbing film, the thermal lens forming layer, the heat insulating layer film, the heat transfer layer film, the light transmitting layer, and the gradient index lens used in the present invention do not impair the functions thereof. In, in order to improve the processability, or to improve the stability and durability of the optical element, containing known additives such as antioxidants, ultraviolet absorbers, singlet oxygen quencher, dispersion aids and the like Is also good.

[Material of Light Absorbing Film] As the light absorbing material used for the light absorbing film in the laminated thin film optical element of the present invention, various known materials can be used.

Specific examples of the light-absorbing material used for the light-absorbing film in the laminated thin-film optical element of the present invention include:
For example, GaAs, GaAsP, GaAlAs, In
P, InSb, InAs, PbTe, InGaAsP,
A single crystal of a compound semiconductor such as ZnSe; a fine particle of the compound semiconductor dispersed in a matrix material; a single crystal of a metal halide (eg, potassium bromide, sodium chloride, etc.) doped with a different metal ion; Microparticles of chloride (eg, copper bromide, copper chloride, cobalt chloride, etc.) dispersed in a matrix material,
CdS, CdS doped with foreign metal ions such as copper
e, a single crystal of cadmium chalcogenide such as CdSeS or CdSeTe, a dispersion of the cadmium chalcogenide fine particles in a matrix material, silicon,
Semiconductor single crystal thin film such as germanium, selenium, tellurium, polycrystalline thin film or porous thin film, semiconductor fine particles such as silicon, germanium, selenium, tellurium dispersed in a matrix material, ruby, alexandrite, garnet, Nd: YAG, Single crystal (so-called laser crystal) corresponding to a gem doped with metal ions such as sapphire, Ti: sapphire, Nd: YLF, lithium niobate (LiNbO ₃ ) doped with metal ions (eg, iron ions), LiB ₃ O ₅ , LiTaO ₃ , KT
ferroelectric crystals such as iOPO ₄ , KH ₂ PO ₄ , KNbO ₃ , BaB ₂ O ₂ , quartz glass doped with metal ions (eg, neodymium ion, erbium ion, etc.);
In addition to soda glass, borosilicate glass, other glass, and the like, a material in which a dye is dissolved or dispersed in a matrix material, and an amorphous dye aggregate can be suitably used.

Among these, those in which a dye is dissolved or dispersed in a matrix material are particularly suitable in the present invention because they have a wide selection range of the matrix material and the dye and can be easily processed into a laminated thin-film optical element. Can be used.

Specific examples of the dye which can be used in the present invention include, for example, xanthene dyes such as rhodamine B, rhodamine 6G, eosin and phloxin B, acridine dyes such as acridine orange and acridine red, ethyl red, methyl Azo dyes such as red, porphyrin dyes, phthalocyanine dyes, cyanine dyes such as 3,3′-diethylthiacarbocyanine iodide, 3,3′-diethyloxadicarbocyanine iodide, ethyl violet, Victoria Blue R and other triarylmethane dyes, naphthoquinone dyes, anthraquinone dyes, naphthalenetetracarboxylic diimide dyes, perylenetetracarboxylic diimide dyes, and the like can be preferably used.

In the present invention, these dyes can be used alone or in combination of two or more.

The matrix material that can be used in the present invention includes (1) high transmittance in the wavelength region of light used in the light control method of the present invention, and (2) dye or various fine particles used in the present invention. Any one can be used as long as it satisfies the condition that it can be dissolved or dispersed with good stability.

As the inorganic matrix material, for example, a single crystal of a metal halide, a single crystal of a metal oxide, a single crystal of a metal chalcogenide, quartz glass, soda glass, borosilicate glass, etc., or a so-called sol-gel method can be used. For example, a low-melting glass material obtained can be used.

Further, as the organic matrix material, for example, various organic polymer materials can be used. Specific examples thereof include polystyrene, poly (α-methylstyrene), polyindene, and poly (4-methyl-1).
-Pentene), polyvinylpyridine, polyvinylformal, polyvinylacetal, polyvinylbutyral,
Polyvinyl acetate, polyvinyl alcohol, polyvinyl chloride, polyvinylidene chloride, polyvinyl methyl ether,
Polyvinyl ethyl ether, polyvinyl benzyl ether, polyvinyl methyl ketone, poly (N-vinylcarbazole), poly (N-vinylpyrrolidone), polymethyl acrylate, polyethyl acrylate, polyacrylic acid,
Polyacrylonitrile, polymethyl methacrylate, polyethyl methacrylate, polybutyl methacrylate, polybenzyl methacrylate, polycyclohexyl methacrylate, polymethacrylic acid, polymethacrylamide, polymethacrylonitrile, polyacetaldehyde, polychloral, polyethylene oxide , Polypropylene oxide, polyethylene terephthalate, polybutylene terephthalate, polycarbonates (bisphenols + carbonate), poly (diethylene glycol / bisallyl carbonate), 6-nylon, 6,6-nylon, 12-
Nylon, 6,12-nylon, polyethyl aspartate, polyethylglutamate, polylysine, polyproline, poly (γ-benzyl-L-glutamate), methylcellulose, ethylcellulose, benzylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, acetylcellulose, Cellulose triacetate, cellulose tributyrate, alkyd resin (phthalic anhydride + glycerin), fatty acid-modified alkyd resin (fatty acid + phthalic anhydride + glycerin), unsaturated polyester resin (maleic anhydride + phthalic anhydride + propylene glycol), epoxy Resin (bisphenols + epichlorohydrin), polyurethane resin, phenol resin, urea resin, melamine resin, xylene resin, toluene resin, guanamine resin Which resin, organic polysilane such as poly (phenyl methyl silane), organic polygermane and polycondensate these copolymers, both are mentioned. Also,
A polymer compound obtained by plasma-polymerizing a compound having no normal polymerizability, such as carbon disulfide, carbon tetrafluoride, ethylbenzene, perfluorobenzene, perfluorocyclohexane, or trimethylchlorosilane, can be used. Furthermore, those in which a residue of a dye is bonded to these organic polymer compounds as a side chain of a monomer unit, or as a cross-linking group, as a copolymerized monomer unit, or as a polymerization initiation terminal can be used as a matrix material. .

A known method can be used to dissolve or disperse the dye in these matrix materials. For example, a method of dissolving and mixing a dye and a matrix material in a common solvent and then removing the solvent by evaporating the solvent,
A method of forming a matrix material by dissolving or dispersing a dye in a raw material solution of an inorganic matrix material produced by a sol-gel method, into a monomer of an organic polymer matrix material, using a solvent as necessary, A method of forming a matrix material by polymerizing or polycondensing the monomer after dissolving or dispersing, a method in which a dye and an organic polymer matrix material are dissolved in a common solvent, and a dye and a thermoplastic organic polymer are used. A method in which both of the matrix materials are dropped into a solvent in which both are insoluble, a generated precipitate is separated by filtration, dried, and then heated and melt-processed can be suitably used. By devising a combination of a dye and a matrix material and a processing method, the dye molecules are aggregated, and “H
It is known that special aggregates called "aggregates" and "J-aggregates" can be formed, but the dye molecules in the matrix material are used under conditions that form such aggregates or aggregates. May be.

A known method can be used to disperse the various fine particles in these matrix materials. For example, after dispersing the fine particles in a solution of a matrix material, or a solution of a precursor of the matrix material, a method of removing the solvent, into the monomer of the organic polymer matrix material, using a solvent as necessary, A method of forming a matrix material by polymerizing or polycondensing the monomer after dispersing the fine particles, a metal salt such as cadmium perchlorate or gold chloride as a precursor of the fine particles into an organic polymer matrix material. After dissolving or dispersing, a method of depositing fine particles of cadmium sulfide by treating with hydrogen sulfide gas or gold particles by heat treatment in a matrix material, a chemical vapor deposition method, a sputtering method, etc. It can be suitably used.

When the dye alone can be present as an amorphous thin film with little light scattering (amorphous), an amorphous dye film may be used as the light absorbing film without using a matrix material. it can.

When the dye alone can be present as a microcrystalline aggregate which does not cause light scattering, the microcrystalline aggregate of the dye can be used as a light absorbing film without using a matrix material. . As in the stacked thin-film optical element of the present invention, the pigment microcrystal aggregate as a light absorbing film is formed by a thermal lens forming layer (eg, resin), a heat transfer layer film (eg, glass), and / or a heat insulating layer film (eg, resin). ), The particle size of the dye microcrystals is １ ／ of the shorter wavelength of the signal light wavelength and the control light wavelength.
When the size does not exceed, light scattering does not substantially occur.

[Combination of Light Absorbing Material, Wavelength Band of Signal Light, and Wavelength Band of Control Light] Light absorbing material, signal used in the laminated thin film optical element, light control method and light control device of the present invention As the wavelength band of the light and the wavelength band of the control light, an appropriate combination can be selected and used depending on the purpose of use.

As a specific setting procedure, for example, first, the wavelength or the wavelength band of the signal light is determined according to the purpose of use, and the optimal combination of the light absorbing material and the wavelength of the control light is used to control this. Should be selected. Alternatively, after determining the combination of the wavelengths of the signal light and the control light according to the purpose of use, a light-absorbing material suitable for this combination may be selected.

[Composition of light-absorbing material, thickness of light-absorbing film in light-absorbing layer, and thickness of thermal lens forming layer] In the laminated thin-film optical element of the present invention, the light-absorbing layer is composed of three layers. A laminated thin film, as a first layer, a light absorbing film that absorbs light in the wavelength band of the control light, and as a second layer, a thermal lens forming layer having optical transparency in the wavelength band of the control light and the signal light A light absorbing film for absorbing light in the wavelength band of the control light is laminated as the third layer. Further, it is preferable that the thickness of the light absorption layer composed of the laminated thin film does not exceed twice the confocal distance of the converged control light. Further, in order to achieve a higher response speed, it is preferable that the thickness of the light absorption layer formed of the laminated thin film does not exceed one time the confocal distance of the converged control light.

Under such conditions, the composition of the light absorbing material used in the present invention and the light absorbing film (2
The film thickness of the sheet can be set based on the transmittance of the control light and the signal light passing through the light absorbing layer as a combination thereof. For example, first, among the compositions of the light-absorbing material, at least the concentration of a component that absorbs control light or signal light is determined, and then the transmittance of control light and signal light transmitted through the laminated thin-film optical element is specified. The thickness of the light absorbing film (two sheets) in the light absorbing layer can be set to a value. Alternatively, first, for example, as required in the device design, the thickness of the light absorbing film (two sheets) in the light absorbing layer is set to a specific value, and then the control light and the signal transmitted through the laminated thin film optical element are set. The composition of the light absorbing material can be adjusted so that the light transmittance has a specific value.

An object of the present invention is to provide a light control method and a light control device which can obtain a sufficient size and a higher speed light response from a laminated thin film optical element with a light power as low as possible. The values of the transmittances of the control light and the signal light that pass through the light absorbing layer and are optimal for achieving this object are as follows.

In the laminated thin film optical device, the light control method and the light control device according to the present invention, the light absorption is such that the transmittance of the control light propagating through the light absorbing layer in the laminated thin film optical device is at most 90% or less. It is recommended to control the concentration and existence state of the light absorbing component in the conductive material, and to set the thickness of the light absorbing film (two sheets) in the light absorbing layer.

On the other hand, when the control light is not irradiated,
Control of the concentration and existence state of the light absorbing component in the light absorbing material so that the transmittance of the signal light propagating through the light absorbing layer in the laminated thin film optical element becomes at least 10% or more, light absorption in the light absorbing layer It is recommended to set the thickness of the film (two sheets).
Preferably, the concentration of the light absorbing component is increased, and the thickness of the light absorbing film (two sheets) is reduced.

Here, 2 sandwiching the light transmitting thermal lens forming layer
The thicknesses of the light absorbing films need not be the same, and may be any thickness that satisfies the above-described transmittance as a total.

In particular, of the two light absorbing films, the light absorbing film on the control light incident side is 10 to 90% of the control light.
So that the light absorbing film on the control light emitting side absorbs the remainder of the control light (for example, the concentration of the light absorbing component in the light absorbing material and the light absorbing layer). The thickness of the heat absorbing film (two sheets) is controlled, and the transmittance of the two light absorbing films in the control light wavelength band is adjusted, so that the thermal lens forming layer is sandwiched.
The control light is absorbed by both of the light absorbing films, and as a result, the formation and disappearance of the thermal lens can be extremely smoothly caused. Regarding the allocation of the transmittance between the control light incidence side and the control light emission side of the two light absorbing films, for example, 10:90, 20:80, 30:70, 40: 6
0, 50:50, 60:40, 70:30, 80: 2
Combinations such as 0, 90:10 can be used.

The total thickness of the two light absorbing films is determined according to the desired transmittance of the signal light propagating through the light absorbing layer in the above-mentioned laminated thin film optical element. The upper limit of the preferable thickness of the thermal lens forming layer that satisfies the above conditions is determined according to the allocation of the transmittance.

The lower limit of the thickness of the thermal lens forming layer in the light absorbing layer is selected according to the material of the thermal lens forming layer as described below.

[Material of Thermal Lens Forming Layer in Light Absorbing Layer and Thickness of Thermal Lens Forming Layer] As a material of the thermal lens forming layer in the light absorbing layer, liquid, liquid crystal and solid materials can be used. it can. In particular, it is preferable that the thermal lens forming layer be made of an organic compound selected from the group consisting of an amorphous organic compound, an organic compound liquid, and a liquid crystal. When the material of the thermal lens forming layer is a liquid crystal or a liquid, for example, a light absorbing film and / or a heat transfer layer film is formed of a material having a self-shape retention, and depletion corresponding to the thickness of the thermal lens forming layer is reduced. The thermal lens forming layer can be formed by injecting the thermal lens forming layer material in a fluid state into the thermal lens forming layer. on the other hand,
When the material of the thermal lens forming layer is solid, it may be formed by laminating a light absorbing film on both sides of the thermal lens forming layer.

The material of the thermal lens forming layer is not limited to a single material. For example, a plurality of types of solid laminated films may be used.
Further, a stack of a solid and a liquid may be used.

The thickness of the thermal lens forming layer depends on the type of material used, but may be in the range of several nanometers to several hundreds of micrometers, and may be in the range of several tens of nanometers to several tens of micrometers. It is particularly suitable.

As described above, the total thickness of the light absorbing layer formed by laminating the thermal lens forming layer and the two light absorbing films does not exceed twice the confocal distance of the converged control light. Is preferred.

As the material of the thermal lens forming layer in the light absorbing layer, liquid, liquid crystal, and solid materials can be used. In any case, a material having a large temperature dependence of the refractive index is preferable.

Typical values of the physical properties of the organic compound liquid and water depending on the refractive index and temperature are described in the literature [D. Solimini: J. Appl.
s., vol. 37, 3314 (1966)]. Wavelength 633
Temperature change of refractive index for light of nm [unit: 1 / K]
Is more methanol (3.9 × 10 ⁻⁴ ) than water (0.8 × 10 ⁻⁴ ).
Alcohol such as 10 ^-4 ), cyclopentane (5.7 × 10 ^-4 ) and benzene (6.4 × 1
^0-4 ), chloroform (5.8 × ^10-4 ), benzene (6.4 × ^10-4 ) and carbon disulfide (7.7 × ^10-4 ).

When a liquid crystal is used as the material of the thermal lens forming layer in the light absorbing layer, any known liquid crystal can be used. Specifically, various cholesterol derivatives, 4'-n-butoxybenzylidene-4-cyanoaniline, 4'-n-hexylbenzylidene-4-
4'-alkoxybenzylidene such as cyanoaniline-
4-cyanoanilines, 4'-ethoxybenzylidene-
4'-alkoxybenzylideneanilines such as 4-n-butylaniline, 4'-methoxybenzylideneaminoazobenzene, 4- (4'-methoxybenzylidene) aminobiphenyl, 4- (4'-methoxybenzylidene) aminostilbene, 4 ' -Cyanobenzylidene-4-n
-Butoxyaniline, 4'-cyanobenzylidene-4
-4'-cyanobenzylidene-4-alkoxyanilines such as n-hexyloxyaniline, 4'-n-butoxycarbonyloxybenzylidene-4-methoxyaniline, p-carboxyphenyl n-amyl carbonate, n-heptyl / 4 Carbonates such as-(4'-ethoxyphenoxycarbonyl) phenyl carbonate, 4-n-butylbenzoic acid / 4'-ethoxyphenyl, 4-n-butylbenzoic acid / 4'-octyloxyphenyl, 4-n- 4-alkylbenzoic acid / 4'-alkoxyphenyl esters such as pentylbenzoic acid / 4'-hexyloxyphenyl, 4,4'-di-n-amyloxyazoxybenzene, 4,4'-di-n- Azoxybenzene derivatives such as nonyloxyazoxybenzene,
4-cyano-4 such as 4-cyano-4'-n-octylbiphenyl, 4-cyano-4'-n-dodecylbiphenyl
Liquid crystals such as 4'-alkylbiphenyls, and (2
S, 3S) -3-Methyl-2-chloropentanoic acid · 4 ′, 4 ″ -octyloxybiphenyl, 4 ′-(2
-Methylbutyl) biphenyl-4-carboxylic acid-4-hexyloxyphenyl, 4'-octylbiphenyl-4
-Ferroelectric liquid crystals such as 4- (2-methylbutyl) phenyl carboxylate can be used.

When a solid material is used as the material of the thermal lens forming layer in the light absorbing layer, an amorphous organic compound which has small light scattering and a large temperature dependence of the refractive index is particularly suitable. Specifically, similarly to the matrix material, a material known as an optical resin can be selected from various organic polymer materials and used. Refractive index of optical resin described in the literature [Technical Information Association of Japan, "Development of latest optical resin, design of characteristics and high-precision parts, molding technology", Technical Information Association (1993), p.35] Temperature change [unit: 1 /
K] is, for example, poly (methyl methacrylate) 1.2 ×
10 ^-4 , 1.4 × 10 ^-4 polycarbonate, and 1.5 × 10 ^-4 polystyrene. These resins can be suitably used as a material of the thermal lens forming layer in the light absorbing layer.

The organic solvent has a merit that the temperature dependence of the refractive index is greater than that of the optical resin, but on the other hand, there is a problem that when the temperature rise due to the control light irradiation reaches the boiling point of the organic solvent, the organic solvent boils. (There is no problem when using a solvent having a high boiling point). On the other hand, an optical resin from which volatile impurities have been thoroughly removed can be used, for example, in the case of polycarbonate, even under severe conditions where the temperature rise due to control light irradiation exceeds 250 ° C.

[Insulation Layer Film] When a gas is used as the insulation layer film, an inert gas such as nitrogen, helium, neon, argon or the like can be suitably used in addition to air.

When a liquid is used as the heat insulating layer film, it is made of a material having a thermal conductivity equal to or smaller than that of the light absorbing layer, transmitting control light and signal light, and forming a material of the light absorbing layer. Any liquid can be used as long as it does not dissolve or corrode the compound. For example, when the light absorption layer is made of polymethyl methacrylate containing a cyanine dye, liquid paraffin can be used.

When a solid is used as the heat insulating layer film, a material having a heat conductivity equal to or smaller than that of the light absorbing layer (the light absorbing film and the thermal lens forming layer) and a control light and a signal light are used. Any solid can be used as long as it transmits light and does not react with the material of the light absorbing layer or the heat transfer layer film. For example, when the light absorption film is made of polymethyl methacrylate containing a cyanine dye, polymethyl methacrylate containing no dye [thermal conductivity of 0.15 at 300 K] is used.
Wm ^-1 K ^-1 ] can be used as the heat insulating layer film.

[Material of Heat Transfer Layer Film] The heat transfer layer film is preferably made of a material having a higher thermal conductivity than that of the light absorption layer, and transmits control light and signal light, and is made of a material of the light absorption layer and the heat insulation layer film. Any substance can be used as long as it does not react with the compound. Examples of materials having high thermal conductivity and low light absorption in the visible light wavelength band include diamond [thermal conductivity at 300 K of 900 Wm ^-1 K ^-1 ], sapphire [46 Wm ^-1 K ^-1 ] and quartz. Single crystal [10.4 Wm ^-1 K ^-1 in the direction parallel to the c-axis], quartz glass [1.3 in the direction parallel to the c-axis]
8Wm ^-1 K ^-1 ] and hard glass [1.10 Wm ^-1 K ^-1 ]
And the like can be suitably used as the heat transfer layer film.

[Material of Light-Transmissive Layer] In one embodiment of the laminated thin-film optical element of the present invention, a gradient-index lens as a means for converging the control light is provided through a light-transmitting layer. The light transmitting layer is characterized by being laminated on the incident side, and the material of the light transmitting layer is a solid heat insulating layer film and / or
Alternatively, the same material as the material of the heat transfer layer film can be used. The light transmitting layer is not only for literally transmitting the control light and the signal light efficiently, but also for bonding the gradient index lens as a component of the laminated thin film optical element. Among the so-called ultraviolet curable resins and electron beam curable resins, those having a high light transmittance in the wavelength band of the control light and the signal light can be particularly preferably used.

[Method of Manufacturing Laminated Thin-Film Optical Device] The method of manufacturing the laminated thin-film optical device of the present invention is arbitrarily selected according to the structure of the stacked thin-film optical device and the type of material used.
A known method can be used.

For example, when the light-absorbing material used in the light-absorbing film in the laminated thin-film optical element is a single crystal as described above, the light-absorbing film is formed by cutting and polishing the single crystal. Can be.

For example, a light absorbing film made of a matrix material containing a dye, a thermal lens forming layer made of an optical resin, and an optical glass used in combination as a heat conductive layer film are used. When a laminated thin-film optical element having a structure of “thermal lens forming layer / light absorbing film / heat transfer layer film” is formed, first, a light absorbing film is formed on the heat transfer layer film by the methods listed below. be able to.

A solution in which a dye and a matrix material are dissolved is coated on a glass plate used as a heat transfer layer film,
Blade coating, roll coating, spin coating,
Coating by coating method such as dipping method, spray method, or lithographic, letterpress, intaglio, stencil, screen,
A method of forming a light absorbing film by printing by a printing method such as transfer may be used. In this case, a method of preparing an inorganic matrix material by a sol-gel method can be used for forming the light absorbing film.

Electrochemical deposition methods such as an electrodeposition method, an electrolytic polymerization method, and a micellar electrolytic method (JP-A-63-243298) can be used.

Further, a Langmuir-Blodgett method for transferring a monomolecular film formed on water can be used.

As a method utilizing the polymerization or polycondensation reaction of the raw material monomers, for example, when the monomer is a liquid, a casting method, a reaction injection molding method, a plasma polymerization method, a photopolymerization method and the like can be mentioned.

Sublimation transfer method, evaporation method, vacuum evaporation method, ion beam method, sputtering method, plasma polymerization method, CVD
Method, an organic molecular beam evaporation method, or the like can also be used.

A composite characterized in that two or more organic optical materials are sprayed in the form of a solution or dispersion from a spray nozzle provided for each component into a high vacuum vessel, deposited on a substrate, and heated. Method of Manufacturing Optical Optical Thin Film (Patent Publication No. 25)
No. 99569) can also be used.

The method for forming a solid light absorbing film as described above can be suitably used, for example, when forming a heat insulating layer film made of a solid organic polymer material.

Next, when a thermal lens forming layer is formed by using a thermoplastic optical resin, a "heat transfer layer film / light absorbing film / heat absorbing film / heat absorbing film" is formed by using a vacuum hot press method (Japanese Patent Laid-Open No. 4-99609). A laminated thin-film optical element having a structure of “lens forming layer / light absorbing film / heat transfer layer film” can be produced. That is, a powder or a sheet of a thermoplastic optical resin is sandwiched between two heat transfer layer films (glass plates) each having a light absorbing film formed on the surface by the above-described method, and heated and pressed under a high vacuum. A stacked thin film element having the above structure can be manufactured.

[Material of Refractive Index Lens and Method of Making]
In one embodiment of the laminated thin film optical element of the present invention, a gradient index lens as the control light converging means is provided by being laminated on the control light incident side via a light transmitting layer. However, any known material and method for forming the gradient index lens can be used.

For example, a gradient index lens of a gradient index type can be made of an organic polymer material by utilizing the permeation / diffusion phenomenon of a monomer [M. Oikawa, K. Iga, T. San.
ada: Jpn. J. Appl. Phys, 20 (1), L51-L54 (1981)]. That is, by the monomer exchange technique, the gradient index lens can be monolithically formed on a flat substrate, for example,
Methyl methacrylate (n
= 1.494) is diffused around a 3.6 mmφ circular disk mask into a flat plastic substrate of polyisophthalic diacrylic acid (n = 1.570) with a high refractive index.

In addition, a refractive index distribution type gradient index lens can be made of an inorganic glass material by utilizing the diffusion phenomenon of inorganic ions [M. Oikawa, K. Iga: Appl. Opt., 21
(6), 1052-1056 (1982)]. That is, after a mask is attached to a glass substrate, a circular window having a diameter of about 100 μm is provided by a photolithographic technique, and an electric field is applied for several hours to form a refractive index distribution by ion exchange by immersion in a molten salt. By promoting ion exchange
For example, a diameter of 0.9 mm, a focal length of 2 mm, and a numerical aperture NA
= 0.23 can be formed.

[Calculation of Beam Waist Diameter] In order to increase the optical response in the light control method of the present invention, a region near the focal point where the photon density is the highest, that is, “beam waist”
The shape and size of the beam cross section of the signal light and the control light are set so that the beam cross section of the signal light does not exceed the beam cross section of the control light in the region where the photon density near the focal point is the highest. Is preferred.

Hereinafter, the case of a Gaussian beam in which the amplitude distribution of the electric field in the beam section in the traveling direction, that is, the energy distribution of the light beam has a Gaussian distribution, will be described. In the following description, a case will be described in which a condensing lens (refractive index type lens) is used as the beam converging means, but the same applies even if the converging means is a concave mirror or a refractive index dispersive lens.

FIG. 8 shows the state of the light beam and the wavefront 30 in the vicinity of the focal point Fc when the Gaussian beam is converged by the condenser lens 7 at an opening angle of 2θ. Where the wavelength λ
The position where the diameter 2ω of the Gaussian beam becomes minimum is called “beam waist”. Hereinafter, the beam waist diameter is set to 2ω ₀
It shall be represented by Due to the diffraction effect of light, 2ω ₀ does not become zero but has a finite value. Note that the beam radius ω and ω
The definition of ₀ is the distance when the position where the energy becomes 1 / e ² (e is the base of natural logarithm) is measured from the beam center with reference to the energy of the beam center portion of the Gaussian beam. Of course, at the center of the beam waist, the photon density is highest.

In the case of a Gaussian beam, the beam divergence angle θ sufficiently far from the beam waist is related to the wavelength λ and the beam waist diameter ω ₀ by the following equation (2).

[0097]

Π · θ · ω ₀ λλ (2) where π is a circular constant.

Only when the condition of “sufficiently distant from the beam waist” is satisfied, this formula is used to calculate the focal length of the condenser lens from the beam radius ω incident on the condenser lens, the numerical aperture of the condenser lens, and the focal length. Beam waist diameter ω
₀ can be calculated.

More generally, the beam waist diameter 2 when a parallel Gaussian beam (wavelength λ) having a beam radius ω is converged by a condenser lens having an effective aperture radius a and a numerical aperture NA.
ω ₀ can be expressed by the following equation (3).

[0100]

2ω ₀ ｋ k · λ / NA (3) Here, since the coefficient k cannot be solved algebraically, it is determined by performing a numerical analysis calculation on the light intensity distribution on the lens image plane. can do.

When the numerical analysis calculation is performed while changing the ratio between the beam radius ω incident on the condenser lens and the effective aperture radius a of the condenser lens, the value of the coefficient k in the equation (3) is obtained as follows.

[0102]

When a / ω = 1, k ≒ 0.92 when a / ω = 2, k ≒ 1.3 when a / ω = 3, k ≒ 1.9 when a / ω = 3, and k ≒ 3 when a / ω = 4. That is, the smaller the beam radius ω is than the effective aperture radius a of the condenser lens, the larger the beam waist diameter ω ₀ is.

For example, a focal length of 6.2 as a condenser lens
mm, a numerical aperture of 0.65, and an effective aperture radius of about 4 mm. When signal light having a wavelength of 780 nm is converged, if the beam radius ω incident on the condenser lens is 4 mm, a / ω
Is about 1, the beam waist radius ω ₀ is 0.55 μm,
If ω is 1 mm, a / ω is approximately 4 and ω ₀ is calculated to be 1.8 μm. Similarly, when the control light having the wavelength of 633 nm is converged, if the beam radius ω is 4 mm, a / ω is about 1
And the beam waist radius ω ₀ is 0.45 μm and ω is 1
If mm, a / ω is calculated to be about 4 and ω ₀ is calculated to be 1.5 μm.

As is apparent from this calculation example, in order to minimize the cross-sectional area of the light beam at the region where the photon density is highest near the focal point of the condensing lens, that is, at the beam waist, the condensing lens can receive light at the maximum. The beam diameter may be expanded (beam expanded) to the limit. Also, when the diameter of the beam incident on the condenser lens is the same, it can be seen that the shorter the wavelength of the light, the smaller the beam waist diameter.

As described above, in order to increase the optical response in the light control method of the present invention, the beam cross-sectional area of the signal light in the region where the photon density is the highest near the focal point is such that the photon density near the focal point is the highest. It is preferable to set the shapes and sizes of the beam cross sections of the signal light and the control light so as not to exceed the beam cross section of the control light in the region. If a Gaussian beam is used for both the signal light and the control light, the signal light and the control light are controlled according to the wavelength in the state of the parallel beam before being converged by the converging means such as the condenser lens according to the above description and the calculation formula. By adjusting the beam diameter of the light, for example, by expanding the beam as necessary, the beam cross-sectional area of the signal light in the region where the photon density near the focal point is the highest is the region where the photon density near the focal point is the highest. The beam cross-sectional area of the control light at the time of (1) is not exceeded. As a beam expanding unit, a known unit, for example, a Kepler-type optical system including two convex lenses can be used.

[Calculation of Confocal Distance Zc] As described above, in the case of a Gaussian beam, the vicinity of the beam waist of the light beam converged by the converging means such as a convex lens, that is, the section of the confocal distance Zc across the focal point. in the convergent beam it can be regarded as substantially parallel light, the confocal length Zc can be expressed by the circular constant [pi, the beam waist radius omega ₀ and equation using the wavelength lambda (1).

[0107]

To [number 5] ^{_{Zc = πω 0 2 / λ ...}} ω 0 of equation (1) (1) Substituting equation (3), equation (4) is obtained.

[0108]

Zc ≒ π (k / NA) ² λ / 4 (4) For example, a lens having a focal length of 6.2 mm, a numerical aperture of 0.65, and an effective aperture radius of about 4 mm is used as a condenser lens, and has a wavelength of 780 nm. A / ω is about 1, if the beam radius ω incident on the condenser lens is 4 mm, the beam waist radius ω ₀ is 0.55 μm, and the confocal distance Z
If c is 1.23 μm and ω is 1 mm, a / ω is about 4, ω ₀ is 1.8 μm, and confocal distance Zc is calculated as 13.1 μm. Similarly, when the control light having the wavelength of 633 nm is converged, if the beam radius ω is 4 mm, a / ω is about 1
The beam waist radius ω ₀ is 0.45 μm, the confocal distance Zc is 0.996 μm, and if ω is 1 mm, a / ω
Is about 4, ω ₀ is 1.5 μm, and confocal distance Zc is 10.6
It is calculated as μm.

[Optimal Film Thickness of Light Absorbing Layer] A sample was prepared by changing the thickness of the thermal lens forming layer without changing the thickness of the two light absorbing films constituting the light absorbing layer, and keeping the optical density constant. As a result of experiments on a plurality of stacked thin film optical elements having different film thicknesses, when the upper limit of the film thickness of the light absorbing layer is set to twice the confocal distance Zc calculated as described above, the light control method of the present invention It has been found that the photoresponse speed becomes sufficiently high.

The lower limit of the film thickness of the light absorbing layer is preferably as thin as possible, as long as the optical response can be detected.

Control light is incident on a light absorbing layer having a laminated thin film structure of a light absorbing film / thermal lens forming layer / light absorbing film structure.
When 10 to 90% of the control light is absorbed by the light absorbing film on the incident side and the remainder of the control light is then absorbed by the light absorbing film on the outgoing side, twice the confocal distance Zc is set to the light absorbing layer. When the thickness of the light absorbing layer is reduced as the upper limit of the film thickness, the thermal lenses formed at the two positions of the control light incident side and the output side work integrally, and the thermal lens is formed. When,
The extinguishing when the control light is turned off is performed extremely efficiently, and a high-speed response is achieved.

[Thickness of Thermal Insulation Layer Film] The thickness of the thermal insulation layer film includes:
There are optimal values (lower and upper limits) that maximize the magnitude and / or speed of the light response. The value can be experimentally determined according to the configuration of the laminated thin film optical element, the material and thickness of the light absorbing layer, the material of the heat insulating layer film, the material and the thickness of the heat transfer layer film, and the like. For example, ordinary borosilicate glass is used as the heat transfer layer film, polycarbonate is used as the material of the heat insulation layer film and the thermal lens forming layer, and platinum phthalocyanine is used as the light absorption film. The glass (heat transfer layer film 81, 150 μm thick) ) / Polycarbonate resin layer (heat insulating layer) / platinum phthalocyanine vapor deposited film (light absorbing film 84, film thickness 0.2 μm) / polycarbonate resin layer (thermal lens forming layer 80, film thickness 20 μm) / platinum phthalocyanine vapor deposited film (light absorbing film) 85, film thickness 0.2 μm) / polycarbonate resin layer (heat insulating layer) / glass (heat transfer layer film 8)
6, 150 μm), the thickness of the heat insulating layer is preferably 5 nm to 5 μm, more preferably 50 nm to 500 nm.
It is.

[Thickness of heat transfer layer film]
There is an optimal value (lower limit in this case) that maximizes the magnitude and / or speed of the light response. The value can be experimentally determined according to the configuration of the laminated thin-film optical element, the material and thickness of the light absorbing layer, the material and thickness of the heat insulating layer, the material of the heat transfer layer film, and the like. For example, a normal borosilicate glass as a heat transfer layer film, a polycarbonate as a material of a heat insulating layer film and a thermal lens forming layer, a platinum phthalocyanine vapor deposition film as a light absorption film, and a glass (heat transfer layer film 8).
1, thickness of 150 μm) / polycarbonate resin layer (heat insulating layer) / platinum phthalocyanine deposited film (light absorbing film 84,
0.2 μm thick) / polycarbonate resin layer (thermal lens forming layer 80, 20 μm thick) / platinum phthalocyanine deposited film (light absorbing film 85, 0.2 μm thick) / polycarbonate resin layer (heat insulating layer) / glass When a laminated thin-film optical element having a configuration of (thermal layer film 86, film thickness 150 μm) is formed, the lower limit of the thickness of the heat transfer layer film is preferably 10 μm,
More preferably, it is 100 μm. The upper limit of the thickness of the heat transfer layer film is not limited by the magnitude and / or speed of the optical response, but the type, focal length and working distance (working distance) of the condensing lens 7 and light receiving lens 9 used. ) Must be designed.

[0114]

[Embodiment 1] First, an embodiment will be described below in which the laminated thin film optical element of the present invention does not include a gradient index lens.

FIG. 2 is a cross-sectional view illustrating the configuration of the laminated thin-film optical element 8 of this embodiment. As illustrated in FIG. 2, the laminated thin-film optical element 8 according to the present embodiment includes, for example, a heat transfer layer film 81 / a light absorption film 84 / a thermal lens formation layer 80 from the incident side of the control light S1 and the signal light S2. / Light absorbing film 85 / heat transfer layer film 8
6 are stacked in this order. Details of these will be described later.

FIG. 2 shows a schematic configuration of the light control device of this embodiment.

The light control device of the present invention, which is schematically illustrated in FIG. 2, includes a control light source 1, a signal light source 2, an ND filter 3, a shutter 4, a semi-transmissive mirror 5, a light mixer 6, a condenser lens. 7, the laminated thin film optical element 8, the light receiving lens 9, the wavelength selective transmission filter 20, the photodetectors 11 and 22, of the present invention,
And an oscilloscope (not shown). Among these optical elements or optical components, a light source 1 for control light,
The light source 2, the optical mixer 6, the condenser lens 7, the laminated thin-film optical element 8, the light receiving lens 9, and the wavelength selective transmission filter 20 of the signal light implement the light control method of the present invention with the device configuration of FIG. It is an essential component of the device to perform ND
The filter 3, the shutter 4, and the semi-transmissive mirror 5 are provided as necessary. The photodetectors 11 and 22 and the oscilloscope are not necessary for implementing the light control method of the present invention. It is used as necessary as an electronic device for confirming the control operation.

Next, the features and operations of the individual components will be described.

A laser device is preferably used as the control light source 1. The oscillation wavelength and the output are appropriately selected according to the wavelength of the signal light targeted by the light control method of the present invention and the light absorption characteristics of the light absorption layer used. There is no particular limitation on the type of laser oscillation, and any type can be used according to the oscillation wavelength band, output, economy, and the like. Further, the wavelength of the light from the laser light source may be converted by a nonlinear optical element before use. Specifically, for example, an argon ion laser (oscillation wavelength 45
7.9 to 514.5 nm), gas lasers such as helium-neon laser (oscillation wavelength: 633 nm), solid-state lasers such as ruby laser and Nd: YAG laser, dye lasers, semiconductor lasers, and the like can be preferably used. As the light source 2 for signal light, not only coherent light from a laser light source but also non-coherent light can be used. Further, in addition to a light source that provides monochromatic light, such as a laser device, a light-emitting diode, and a neon discharge tube, continuous spectrum light from a tungsten bulb, a metal halide lamp, a xenon discharge tube, or the like may be used as a monochromatic light with a light filter or a monochromator. .

Hereinafter, a light emitted from a semiconductor laser (oscillation wavelength: 780 nm, continuous oscillation output: 5 mW) is beam-shaped and used as a parallel Gaussian beam having a diameter of about 8 mm as a signal light source 2, while helium is used as a control light source 1.・ Neon laser (oscillation wavelength 633 nm, beam diameter about 2 mm
An embodiment will be described in the case of using a parallel beam (beam distribution is Gaussian distribution).

Although the ND filter 3 is not always necessary, the ND filter 3 is used to prevent laser light having an unnecessarily high power from entering the optical parts and optical elements constituting the apparatus. In testing the optical response performance, it is useful for increasing or decreasing the light intensity of the control light. In this example, several types of ND filters were exchanged for the latter purpose.

When a continuous wave laser is used as the control light, the shutter 4 is used to make it blink in a pulse shape. The shutter 4 is an essential component of the device for implementing the light control method of the present invention. is not. That is, when the light source 1 of the control light is a laser that oscillates pulses and is a type of light source that can control the pulse width and oscillation interval, or when the laser light that has been pulse-modulated in advance by appropriate means is used as the light source 1 The shutter 4 need not be provided.

When the shutter 4 is used, any type can be used. For example, an optical chopper, a mechanical shutter, a liquid crystal shutter, an optical Kerr effect shutter, a Pockel cell, a photoacoustic element (AO modulator) And the like can be appropriately selected and used in consideration of the operation speed of the shutter itself.

The semi-transmissive mirror 5 is used in this embodiment to constantly estimate the light intensity of the control light when testing the operation of the light control method of the present invention, and the light splitting ratio can be set arbitrarily. It is.

The light detectors 11 and 22 are provided with the light detectors of the present invention.
It is used for electrically detecting and verifying a change in light intensity due to light control, and for testing the function of the laminated thin film optical element of the present invention. The types of the photodetectors 11 and 22 are arbitrary, and can be appropriately selected and used in consideration of the response speed of the detector itself. For example, a photomultiplier tube, a photodiode, a phototransistor, or the like is used. Can be.

The light receiving signals of the photodetectors 11 and 22 can be monitored by a combination of an AD converter and a computer (not shown), in addition to an oscilloscope.

The optical mixer 6 is used for adjusting the optical paths of the control light and the signal light propagating in the laminated thin-film optical element 8, and uses the light control method and light control device of the present invention. This is one of the important components of the apparatus for implementing the method. Any of a polarizing beam splitter, a non-polarizing beam splitter, and a dichroic mirror can be used, and the light splitting ratio can be arbitrarily set.

The condensing lens 7 serves as a common converging means for the signal light and the control light so as to converge the signal light and the control light adjusted to have the same optical path and irradiate the light to the stacked thin film optical element. And is one of the essential components of the light control method and light control device of the present invention. Any specifications such as the focal length, numerical aperture, F-number, lens configuration, and lens surface coating of the condenser lens 7 can be appropriately used.

In this embodiment, a case where a microscope objective lens having a focal length of 6.2 mm, a numerical aperture of 0.65, and an effective aperture radius of 4.03 mm is used as the condenser lens 7 will be described below.

In this case, the radius ω ₀ and the confocal distance Zc of the light beam at the region where the photon density is the highest near the focal point of the condenser lens, ie, the beam waist, are calculated by the above-described equations (2) and (4). As shown in the calculation example using
Ω ₀ is calculated to be 1.5 μm and Zc is calculated to be 10.6 μm for the control light having a wavelength of 33 nm and a beam diameter of 2 mm.

Similarly, a wavelength of 780 nm and a beam diameter of 8
The radius ω ₀ of the light beam at the beam waist for the signal light of mm is calculated to be 0.55 μm. That is, in the present embodiment, the magnitude relationship between the control light beam and the signal light beam at the beam waist is about 3:
1. The control light is larger at a ratio of about 7: 1 as a beam cross-sectional area.

As described above, when the beam size of the control light at the beam waist is made larger than that of the signal light, the energy density of the signal light convergent beam is increased in a region where the energy density of the control light convergent beam near the focal point of the condenser lens is highest. It is easy to adjust the optical system so that the areas having the highest values are overlapped, and it is hard to be affected by fluctuations of various elements of the optical system. That is, in the vicinity of the focal point, it is not necessary to completely match the optical axis centers of the control light and the signal light, and even if the beam positions of the control light and the signal light fluctuate or drift to some extent, the energy density of the signal light converging beam is reduced. It is possible to adjust the highest area so as not to deviate from the area where the energy density of the control light converging beam is highest.

The light receiving lens 9 is a means for returning the signal light and the control light which have been converged and radiated to the laminated thin-film optical element 8 and transmitted therethrough to a parallel and / or convergent beam. In order to obtain signal light with good reproducibility,
A lens having a numerical aperture smaller than the numerical aperture of the condenser lens 7 is used. In this embodiment, a microscope lens having a numerical aperture of 0.4 was used as the light receiving lens 9. That is, by making the numerical aperture of the light receiving lens 9 smaller than the numerical aperture of the condensing lens 7, it is possible to separate out the light flux of the signal light in a region that has been strongly subjected to intensity modulation and / or light flux density modulation. This makes it possible to detect a sufficiently large signal light with good reproducibility. It is also possible to use a concave mirror instead of the condenser lens and the light receiving lens.

The wavelength selective transmission filter 20 is one of the essential components of the device for implementing the light control method of the present invention with the device configuration shown in FIG. 2, and has the same optical path in the laminated thin film optical element. It is used as one of means for extracting only the signal light from the propagated signal light and control light.

As means for separating the signal light and the control light having different wavelengths from each other, a prism, a diffraction grating, a dichroic mirror or the like can be used.

The wavelength selective transmission filter 20 used in the device configuration of FIG. 2 is designed to completely block light in the wavelength band of control light and efficiently transmit light in the wavelength band of signal light. Any known wavelength selective transmission filter can be used. For example, plastic or glass colored with a dye, glass having a multilayer dielectric film on its surface, or the like can be used.

FIG. 2 shows an example of an embodiment of the laminated thin-film optical element of the present invention. The laminated thin-film optical element 8 having the structure of the heat transfer layer film 81 / light absorption film 84 / thermal lens formation layer 80 / light absorption film 85 / heat transfer layer film 86 shown in FIG. Can be.

A substrate having a center wavelength of 185 nm was placed inside a vacuum vessel for cleaning a substrate connected to a vacuum deposition apparatus via a gate valve.
Two 5W UV lamps and 254n center wavelength
m, an ultraviolet lamp having an output of 5 W is mounted in an arrangement such that ultraviolet light is irradiated on the substrate surface, and the substrate (heat transfer layer film 8
1 and 86) as a glass plate (24 mm × 30 mm ×
0.15 mm), and the inside of the vacuum vessel is filled with clean nitrogen gas that has passed through a gas filter that collects 100% of fine particles having a diameter of 0.05 μm under atmospheric pressure. The atmosphere is cleaned until suspended dust (0.1 μm or more in diameter) and contaminant gas are no longer detected, and then oxygen gas is introduced through a gas filter that collects 100% of fine particles having a diameter of 0.05 μm. Was increased to 60% or more, the ultraviolet lamp was turned on, and the substrate surface was subjected to ultraviolet irradiation treatment and ozone treatment for 1 hour. After the above purifying process is completed by evacuating the vacuum chamber for substrate cleaning, ^10-4 after the following high vacuum Pa, and transferring the substrate to the same 10 ^-4 Pa or less in the vacuum evaporation apparatus of the high vacuum . Platinum phthalocyanine (composition formula: C ₃₂ H ₁₆ N ₈ Pt) previously introduced into the evaporation source was heated by a resistance wire, heated to 600 ° C., and vacuum evaporated on the substrate. The control of the substrate temperature was not particularly performed.
The progress of vapor deposition was monitored by a quartz crystal film thickness meter, and when the film thickness reached 0.2 μm, the shutter of the vapor deposition source was closed to terminate vapor deposition.

FIG. 6 shows a scanning electron micrograph of the surface of the deposited film thus formed on the substrate. From this photograph, it can be seen that platinum phthalocyanine vacuum-deposited under the above conditions exists in the form of particles having an outer diameter of 30 to 50 nm. This particle diameter is one of the wavelength of the signal light (780 nm) and the wavelength of the control light (633 nm) in this embodiment.
/ 10, which is a size that does not cause light scattering.

On the other hand, a solution prepared by dissolving 1 g of polycarbonate resin (Panlite L1250 manufactured by Teijin Chemicals Co., Ltd.) in 19 g of dichloromethane was poured into 300 ml of n-hexane while stirring, and the precipitated resin small lump was filtered.
The powder was washed with water, the solvent was removed in clean air, and pulverized to a fine powder having a particle outer diameter of less than 50 μm. This polycarbonate resin fine powder was gradually heated in a high vacuum container of 10 ⁻⁴ Pa or less and degassed in a temperature range of 100 ° C. to 120 ° C. for 48 hours.

In a clean atmosphere, a high vacuum degassed resin fine powder is sprayed on the platinum phthalocyanine vapor-deposited film formed on the glass substrate previously formed, and platinum phthalocyanine on another glass substrate is further spread thereon. The deposited films are placed one on top of the other, placed on a heating stage placed in a high vacuum container, and evacuated to 10 ^-4 Pa or less, at 240 to 260 ° C.
, And a pressure plate heated to 240 to 260 ° C was pressed, and vacuum hot pressing was performed at a pressure of 5 kgf / cm ² .

According to the above procedure, the glass (heat transfer layer film 8)
1, film thickness 150 μm) / platinum phthalocyanine vapor-deposited film (light absorbing film 84, film thickness 0.2 μm) / polycarbonate resin layer (thermal lens forming layer 80) / platinum phthalocyanine vapor-deposited film (light absorbing film 85, film thickness 0.2 μm) ) / Glass (heat transfer layer film 86, film thickness 150 μm).

By adjusting the amount of the resin powder to be sprayed, the heating temperature and the pressure treatment time (from several minutes to several hours), the thickness of the polycarbonate resin thermal lens forming layer can be reduced to 10 μm.
m, 20 μm, 50 μm and 100 μm. Hereinafter, in the present embodiment, the case where the thickness of the thermal lens forming layer made of polycarbonate resin is 20 μm will be described.
In this case, the total thickness of the dye film / resin layer / dye film constituting the light absorbing layer is 20.4 μm, which is 2 of the confocal distance Zc (10.6 μm) of the convergence control light calculated under the above conditions.
Not more than twice.

Similarly, as Comparative Example 1, glass (heat transfer layer film, thickness 150 μm) / platinum phthalocyanine deposited film (light absorption film, thickness 0.2 μm) / polycarbonate resin layer (thermal lens formation layer) A single-layer light-absorbing film / single-layer thermal lens-forming layer / laminate type thin-film optical element having a structure of (thickness: 20 μm) / glass (heat transfer layer film, 150 μm) was prepared.

Further, as Comparative Example 2, glass (heat transfer layer film, film thickness 150 μm) / polycarbonate resin layer (thermal lens formation layer, film thickness 10 μm) / platinum phthalocyanine vapor-deposited film (light absorbing film, film thickness 0.2 μm) ) / Polycarbonate resin layer (thermal lens forming layer, film thickness 10 μm) / glass (heat transfer layer film, film thickness 150 μm). Created. In this case, the aluminum foil / resin powder / glass plate was vacuum hot-pressed, and the aluminum foil was peeled off from the laminated film to form a polycarbonate resin layer / glass / laminated film, and platinum was formed on the resin layer. The phthalocyanine is vacuum-deposited, and the resin surface of the separately formed polycarbonate resin layer / glass laminated film is vacuum hot-pressed on the deposition surface to obtain “resin / dye-deposited film /
A laminated film called “resin” was created.

A transmittance spectrum of the laminated thin-film optical element (the thickness of the thermal lens forming layer is 20 μm) of the present embodiment fabricated as described above is shown by a curve 121 in FIG. Further, the transmittance spectrum of the light absorbing film single layer / thermal lens forming layer single layer / laminated thin film optical element of Comparative Example 1 is shown by a curve 122 in FIG. Here, a curve 122 in FIG. 7 corresponds to one obtained by extracting a transmittance spectrum of one of the two light absorbing films (dye-deposited films) of the laminated thin-film optical element of this embodiment. That is, the transmittance of the laminated thin-film optical element of this embodiment is determined by the wavelength of the control light (6
It is 1.6% at 33 nm) and 86% at the signal light wavelength (780 nm), but about 90% of the 633 nm light is absorbed by the first light absorbing film, and the remaining part is absorbed by the second light absorbing film. Is interpreted as being absorbed.

In the optical device shown in FIG. 2 having the above-described components, the control beam emitted from the light source 1 passes through the ND filter 3 for adjusting the transmitted light intensity by adjusting the transmittance. The control light passes through a shutter 4 for blinking the control light in a pulse shape, and is split by a semi-transmissive mirror 5.

A part of the control light split by the semi-transmissive mirror 5 is received by the photodetector 11. Here, light source 2
Is turned off, the light source 1 is turned on, and the shutter 4 is opened, the relationship between the light intensity at the light beam irradiation position on the laminated thin film optical element 8 and the signal intensity of the photodetector 11 is measured in advance, and a calibration curve is obtained. If created, the light intensity of the control light incident on the laminated thin-film optical element 8 can be constantly estimated from the signal intensity of the photodetector 11. In this embodiment, N
The power of the control light incident on the laminated thin film optical element 8 was adjusted in the range of 0.5 mW to 10 mW by the D filter 3.

The control light split and reflected by the semi-transmissive mirror 5 is
The light passes through the optical mixer 6 and the condenser lens 7 and is converged on the laminated thin-film optical element 8 and irradiated. After passing through the light receiving lens 9, the light beam of the control light having passed through the laminated thin film optical element 8 is blocked by the wavelength selective transmission filter 20.

The light beam of the signal light emitted from the light source 2 is mixed by the optical mixer 6 so as to propagate along the same optical path as the control light, and passes through the condenser lens 7 to the laminated thin film optical element 8. The light that has converged and illuminated, has passed through the element, passes through the light receiving lens 9 and the wavelength selective transmission filter 20, and is received by the photodetector 22.

An experiment of light control was performed using the optical device of FIG. 2, and a change in light intensity as shown in FIG. 9 or 10 was observed. 9 and / or 10, reference numeral 111 denotes a light receiving signal of the photodetector 11, and reference numerals 222 and 223 denote photodetector 2
2 is a light receiving signal. The difference between the case where the light receiving signal 222 of the photodetector 22 is obtained and the case where 223 is obtained is as follows.

In the arrangement of FIG. 2, the control light and the signal light are converged and made incident on the laminated thin-film optical element 8.
When the minimum converging beam diameter position, that is, the beam waist (focal point Fc) is set near the condensing lens 7 of the laminated thin-film optical element 8 (on the light incident side), the signal light transmitted through the laminated thin-film optical element The optical response 222 in the direction in which is decreased is observed. On the other hand, when the beam waist is set near the light receiving lens 9 of the laminated thin-film optical element 8 (light emission side), the apparent intensity of the signal light transmitted through the laminated thin-film optical element 8 is increased. A light response 223 is observed.

It is assumed that the mechanism that causes such an optical response is due to the following thermal lens effect. The method of verifying the thermal lens effect is described in JP-A-10-26043.
It is described in detail in No. 3 bulletin and the like.

The laminated thin film optical element 8 provided with a light absorbing layer has
When the control light having a wavelength selected from the wavelength band absorbed by the light absorbing layer is converged and irradiated by the condenser lens 7,
The control light is absorbed by the light-absorbing layer, and most of the absorbed light energy is converted into heat energy. First, the temperature of the light-absorbing film (two positions on the incident side and the emission side of the control light) of the control light irradiation part is reduced. Rise, and then the temperature of the adjacent thermal lens forming layer also rises due to heat conduction. The distribution of the temperature rise when a Gaussian beam is used as the control light is similar to the Gaussian distribution, and it is estimated that the beam center portion is large and becomes smaller toward the periphery. Due to such a temperature rise and its distribution, a density change and a refractive index change having a distribution occur in the control light irradiation portion in the light absorbing layer.
Needless to say, the optical action based on the refractive index distribution generated in this way is called a “thermal lens”. When the irradiation of the control light, which triggered the formation of the thermal lens, is stopped, the temperature rise due to light absorption stops, the density change and the refractive index distribution are eliminated, and the thermal lens disappears. That is, the thermal lens is reversibly formed and disappears in response to the intermittent control light.

In the laminated thin-film optical element of the present invention, light absorption of control light occurs in two layers of light absorption films on the incident side and emission side of control light. Light absorbing film / thermal lens forming layer /
The control light is incident on the light absorption layer of the laminated thin film structure having the structure of the light absorption film, and the light absorption film on the incident side emits 10 to 9 control light.
In the case where 0% is absorbed and the remaining control light is absorbed by the light absorbing film on the emission side, twice the confocal distance Zc of the converged control light is set as the upper limit of the film thickness of the light absorbing layer, As the thickness of the light absorbing layer is reduced, the two on the control light incident side and the control light
It is presumed that the thermal lens formed at the location acts as a unit, and the thermal lens is formed and disappears when the control light is turned off very efficiently, and a high-speed response is achieved.

When the beam waist position (focal point Fc) of the control light and the signal light is set close to the condenser lens 7 of the laminated thin-film optical element 8 (on the light incident side), and the control light is irradiated, the irradiation is performed. The refractive index becomes smaller toward the center, and the light in that portion is bent toward the outer periphery of the beam. in this case,
When only the central portion of the signal light beam is extracted and the apparent signal light intensity is measured, the optical response 222 in the direction in which the intensity of the signal light decreases corresponding to the irradiation of the control light is extracted with a sufficient size. Can be.

On the other hand, when the beam waist position (focal point Fc) of the control light and the signal light is set to a position close to the light receiving lens 9 of the laminated thin film optical element 8 (light emission side), and the control light is irradiated, the light is converged. The optical action of the thermal lens formed by the illuminated control light causes the convergence point of the signal light to be similarly converged and illuminated so as to extend to the outside of the laminated thin-film optical element 8. In this case, when only the central portion of the signal light beam is extracted and the apparent signal light intensity is measured, the optical response 223 in the direction in which the intensity of the signal light increases corresponding to the irradiation of the control light has a sufficient magnitude. Can be taken out. As can be easily understood, in the laminated thin-film optical device of the present invention, when the thickness of the light-absorbing layer of the laminated thin-film structure having the structure of the light-absorbing film / thermal lens forming layer / light-absorbing film is reduced, It is practically difficult to set the beam waist position (focal point Fc) of the light and the signal light to a position close to the light receiving lens 9 of the laminated thin-film optical element 8 (light emission side).
That is, when the thickness of the light absorption layer approaches the confocal distance Zc of the converged control light, it becomes indistinguishable from the case where the beam waist position is set on the control light incident side. In particular,
The lower limit is about twice the confocal distance Zc of the control light in which the thickness of the light absorbing layer is converged, and when the thickness exceeds the lower limit, the apparent value of the signal light transmitted through the laminated thin film optical element 8 is apparent. The light response 223 in the direction in which the intensity of the light increases is observed with a sufficient magnitude.

By using the laminated thin film optical element of the present invention, it is possible to cope with intermittent control light as shown in FIG.
The optical response 222 in the direction in which the intensity of the signal light decreases can be accelerated. The details are described below.

First, the light beam of the control light and the light beam of the signal light are focused on the same area within the laminated thin-film optical element 8 by the focal point Fc.
, The optical path from each light source, the optical mixer 6, and the condenser lens 7 were adjusted. Next, the function of the wavelength selection filter 20 was checked. That is, it was confirmed that when the light source 1 was turned on while the light source 2 was turned off and the shutter 4 was opened and closed, no response occurred to the photodetector 22 at all.

Next, fine adjustment was performed so that the focal point Fc was located on the control light incident side of the light absorbing layer in the laminated thin film optical element 8. Further, the power of the control light was adjusted to be 10 mW immediately before the condenser lens 7.

When the light source 1 of the control light is turned on with the shutter 4 closed, and then the light source 2 is turned on at time t1 to irradiate the laminated thin-film optical element 8 with signal light, the light detector 2
The signal strength of 2 increased from level C to level A.

At time t2, the shutter 4 is opened,
When the control light was converged and irradiated on the same optical path as the signal light inside the laminated thin film optical element 8 was propagating, the signal intensity of the photodetector 22 decreased from level A to level B. The response time for this change was less than 0.2 microseconds. That is,
The response time was about 10 times faster than the response time described in JP-A-10-90734 (see Comparative Example 3).

At time t3, the shutter 4 is closed, and the irradiation of the control light to the laminated thin-film optical element is stopped.
Returned from level B to level A.

At time t4, the shutter 4 is opened,
Then, when closed at time t5, the signal intensity of the photodetector 22 decreased from level A to level B, and then returned to level A.

When the light source 2 was turned off at time t6, the output of the photodetector 22 decreased and returned to the level C.

In order to confirm the upper limit of the optical response speed of the laminated thin-film optical element of the present invention, the control light was supplied to the AO modulator controlled by the function generator at a duty ratio of 1: 9. And the control light extinguishing time 9 or the control light extinguishing time 9 and the control light extinguishing time 1 are blinked at high speed and continuously, and the tracking state of the signal light intensity is observed with a storage oscilloscope. An experiment was performed. As a result, with respect to the laminated thin-film optical element of this example, a high-speed "bright" pulse with a control light on time of 125 nanoseconds and a light off time of 1.125 microseconds, and a control light on time of 1.125 microseconds and a light off time It has been confirmed that the signal light intensity change follows up to a high-speed "dark" pulse of 125 nanoseconds.

As described above, the confocal distance of the converged control light Zc =
The case where the total thickness of the light-absorbing light layer is 20.4 μm (thickness of the thermal lens forming layer is 20 μm), which is not more than twice the confocal distance Zc, is described with respect to 10.6 μm. Similarly, when the film thickness of the polycarbonate resin thermal lens forming layer in the light absorbing layer was 10 μm, 50 μm, and 100 μm, the following of the signal light intensity following the flickering of the control light was compared. In the case of the above, it was equivalent to 20 μm. However, the control light having a length of 50 μm, which is more than twice the confocal distance Zc of the control light, could follow up to the “bright” pulse with the control light on time of 1 microsecond and the light off time of 9 microseconds. Further, those having a thickness of 100 μm were up to a “bright” pulse having a control light lighting time of 2 microseconds and a light-off time of 18 microseconds. That is, in order to achieve a high response speed, it is preferable that the thickness of the light absorbing layer does not exceed twice the control light confocal distance Zc.

Comparative Example 1 A glass (heat transfer layer, 150 μm thick) / platinum phthalocyanine vapor-deposited film (light absorbing film, 0.2 μm thick) prepared as Comparative Example 1 as described above.
m) / polycarbonate resin layer (thermal lens forming layer, film thickness: 20 μm) / glass (heat transfer layer, film thickness: 150 μm), light absorbing film single layer / thermal lens forming layer single layer / laminated thin film optical element An optical response experiment was performed in the same manner as in Example 1. The control light and the signal light are incident from the light absorbing film side toward the thermal lens forming layer, and the beam waist (focal point Fc) is located near the condenser lens 7 of the light absorbing layer in the stacked thin film optical element 8 (light Light response 22 in the direction in which the intensity of the signal light decreases in response to the irradiation of the control light.
2 were observed. As a result, the change in the signal light intensity could follow the high-speed blinking of the control light up to the "bright" pulse with the control light on time of 2 microseconds and the light off time of 18 microseconds.

Comparative Example 2 A glass (heat transfer layer, 150 μm thick) / polycarbonate resin layer (thermal lens forming layer, 10 μm thick) prepared as Comparative Example 2 as described above.
m) / Platinum phthalocyanine deposited film (light absorbing film, film thickness 0.2 μm) / polycarbonate resin layer (thermal lens forming layer, film thickness 10 μm) / glass (heat transfer layer, film thickness 150 μm)
A light response experiment was performed on the single-layer light-absorbing film / two-layer thermal-lens-forming layer / laminated thin-film optical element having the configuration m) in the same manner as in Example 1. As a result, the signal light intensity change could follow the high-speed blinking of the control light only up to the "bright" pulse with the control light on time of 20 microseconds and the light off time of 180 microseconds.

Comparative Example 3 According to the method described in JP-A-10-90734, a film type having a structure in which a single light absorption layer of a dye-solubilized resin film type was sandwiched between glass substrates as heat transfer layer films. An optical element was created. That is, as the phthalocyanine derivative, 2,6,10,14- and / or 2,6,10,15- and / or 2,6,1
1,15- and / or 2,7,10,15-tetra (t-butyl) oxyvanadium phthalocyanine (mixture of four substituted regioisomers): 6.81 mg and polybenzyl methacrylate: 1993.2 mg in tetrahydrofuran : 200 ml, added to water: 1000 ml with stirring, and the precipitated precipitate (mixture of phthalocyanine derivative and polymer) was separated by filtration, washed with water, dried under reduced pressure, and pulverized. The obtained mixed powder of the phthalocyanine derivative and the polymer was heated at 40 ° C. for 2 days under an ultra-high vacuum of less than 10 ⁻⁵ Pa to completely remove volatile components such as a residual solvent, and to prepare a photoresponsive composition. A powder was obtained. 20 mg of this powder was placed on a slide glass (25 mm × 7
6 mm x thickness 1.150 mm) and cover glass (1
8mm x 18mm x 0.150mm thickness)
A polymer film (thickness: 75 μm) in which a phthalocyanine derivative was solubilized was formed between a slide glass and a cover glass using a method of heating to 100 ° C. under vacuum and pressure bonding two glass plates (vacuum hot pressing method). . That is, as the film-type optical element of Comparative Example 3, glass (heat transfer layer film, film thickness of 15) was used.
0 μm) / a resin film in which a phthalocyanine derivative was dissolved (light absorbing layer / thermal lens forming layer, film thickness: 75 μm) / glass (heat transfer layer film, film thickness: 1.150 mm). . The transmittance of this film type optical element is 8.8% at the wavelength of control light (633 nm), and the wavelength of signal light (830 nm).
nm) was 84%.

The light source 2 of the signal light has an oscillation wavelength of 830n.
The beam waist position (focal point Fc) of the control light and the signal light is changed in the same manner as in the first embodiment except that a semiconductor laser of m (a continuous oscillation output of 5 mW and a Gaussian beam having a diameter of about 8 mm after beam shaping) is used. In the film-type optical element of Comparative Example 3, the optical response 222 in the direction in which the intensity of the signal light decreases is set at a position close to the condenser lens 7 of the light absorbing layer / thermal lens forming layer (light incident side). As a result, the time required for decreasing the signal light intensity when the control light was turned on was 1.9 microseconds.

Further, the change of the signal light intensity could follow the high-speed blinking of the control light only up to the "bright" pulse with the control light ON time of 2 microseconds and the light-off time of 18 microseconds.

[Embodiment 2] Instead of the condenser lens 7 (a microscope objective lens having a focal length of 6.2 mm, a numerical aperture of 0.65 and an effective aperture radius of 4.03 mm) in the embodiment 1, a numerical aperture of 0.66 is used. A laminated thin-film optical device having a configuration as illustrated in FIG. 3 and a light control device, using a refractive index distribution type lens 70 equivalent to an effective aperture radius of 4 mm laminated on a heat transfer layer film 81 via a light transmission layer 82. Equipment was installed. Light transmission layer 8
A commercially available ultraviolet-curable resin (“Seika Beam VDAL-392” manufactured by Dainichi Seika Kogyo) was used as 2.

The optical response of the laminated thin-film optical element of this example was measured in the same manner as in Example 1, and a high-speed optical response equivalent to that of Example 1 was observed.

[Embodiment 3] Instead of the light receiving lens 9 (a microscope objective lens having a numerical aperture of 0.4) in Embodiment 1,
FIG. 4 shows a configuration in which a refractive index distribution type lens 90 having a numerical aperture of 0.4 is laminated on a heat transfer layer film 86 via a light transmission layer 89.
The laminated type thin-film optical element and the light control device having the configurations as exemplified in (1) are installed. As the light transmitting layer 89, the same ultraviolet curable resin as used in Example 2 was used.

The optical response of the laminated thin-film optical element of this example was measured in the same manner as in Example 1, and a high-speed optical response equivalent to that of Example 1 was observed.

[Embodiment 4] Instead of the condenser lens 7 (the objective lens for a microscope having a focal length of 6.2 mm, a numerical aperture of 0.65, and an effective aperture radius of 4.03 mm in FIG. 1) in Embodiment 1, a numerical aperture is used. Example 1 A refractive index distribution type lens 70 having a diameter of 0.66 and an effective aperture radius of 4 mm was laminated on a heat transfer layer film 81 via a light transmission layer 82, and the optical axis was further aligned with the refractive index distribution type lens 70. In place of the light receiving lens 9 (the objective lens for a microscope having a numerical aperture of 0.4 in FIG. 1), the numerical aperture of 0.2 is used.
A laminated type thin-film optical element and a light control device having a configuration as illustrated in FIG. 5 were installed by using a refractive index distribution type lens 90 equivalent to 4 laminated on a heat transfer layer film 86 via a light transmission layer 89. . As the light transmitting layers 82 and 89, the same ultraviolet curable resin as used in Example 2 was used.

The optical response of the laminated thin-film optical element of this example was measured in the same manner as in Example 1, and a high-speed optical response equivalent to that of Example 1 was observed.

[Example 5] Instead of the vacuum hot pressing method using the polycarbonate resin and the resin powder in Example 1, the same ultraviolet curable resin as used in Example 2 was used to form glass (heat transfer layer). Film 81, film thickness 150 μm) /
Platinum phthalocyanine vapor-deposited film (light absorbing film 84, film thickness 0.2 μm) / ultraviolet curable resin layer (thermal lens forming layer 8)
0, a film thickness of 20 μm) / a platinum phthalocyanine vapor-deposited film (light absorbing film 85, film thickness 0.2 μm) / glass (a heat transfer layer film 86, film thickness 150 μm).

Thereafter, the optical response of the laminated thin-film optical element of this example was measured in the same manner as in Example 1, and a high-speed optical response equivalent to that of Example 1 was observed.

[Embodiment 6] Glass (heat transfer layer film 81) / light absorbing film 84 / liquid (thermal lens forming layer 80) / light absorbing film 8
In order to produce a laminated thin-film optical element having a structure of 5 / glass (heat transfer layer film 86, film thickness 1 mm), an assembling optical cell 810 as shown in FIG. 11 was used.

The assembly type optical cell 810 includes the liquid filling section 81
8 is sandwiched between two plate-like entrance / exit surface glasses 813 (heat transfer layer film 81) and 815 (heat transfer layer film 86), and this is packed with rubber packings 812 and 81.
6, and is fixed in fixing screw holes 824 and 825 using screws (not shown). Introducing pipe 82 attached to fixed frame 817
2 and 823 are introduction holes 82 provided in the fixed frame 817.
1, leading to an introduction hole 820 provided in the rubber packing 816, and then to an introduction hole 819 provided in the entrance / exit surface glass 815.
Can be introduced. The thickness of the filling portion 818, that is, the optical path length that propagates through the thermal lens forming layer when the signal light and / or the control light is vertically incident is determined by the thickness of the spacer 814 at the time of assembly. The material of the spacer 814 used here is polytetrafluoroethylene,
The material of the entrance and exit surface glasses 813 and 815 is fused silica glass, the material of the rubber packings 812 and 815 is ethylene propylene rubber, and the material of the fixing frames 811 and 817 is stainless steel.

In the same manner as in Example 1, the glass plate in Example 1 (24 mm × 30 mm × 0.15 mm)
Incoming / outgoing face glass 813 of the assembled optical cell instead of
Platinum phthalocyanine was vacuum-deposited on one surface of (heat transfer layer film 81) and 815 (heat transfer layer film 86) to a thickness of 0.2 μm. The assembly type optical cell 810 was assembled such that the vapor deposition surfaces faced each other. The thickness of the spacer, that is, the thickness of the thermal lens forming layer was 25 μm. Next, glycerin (boiling point: 290 ° C.) was injected into the liquid filling section 818 as a liquid constituting the thermal lens forming layer 80.
Thus, quartz glass (heat transfer layer film 81, film thickness 1 mm) /
Platinum phthalocyanine deposited film (light absorbing film 84, film thickness 0.2 μm) / glycerin liquid film (thermal lens forming layer 80)
/ Platinum phthalocyanine vapor-deposited film (light-absorbing film 85, film thickness 0.2 μm) / quartz glass (heat-conducting layer film 86, film thickness 1 m)
m) to form a laminated thin film optical element. In addition,
Glycerin has a hygroscopic property, and when water is mixed, water vapor bubbles are generated when the temperature rises to 100 ° C. during irradiation with control light. In order to avoid this, glycerin sufficiently dehydrated using a molecular sieve was injected into the assembled optical cell 810 under a dry nitrogen atmosphere, and the injection port was used in a sealed state.

The optical response of the laminated thin-film optical element of this example was measured in the same manner as in Example 1, and a high-speed optical response equivalent to that of Example 1 was observed.

[Embodiment 7] In the same manner as in Embodiment 6, the entrance / exit surface glass 813 of the assembly type optical cell 810 is set.
Platinum phthalocyanine was vacuum-deposited on one surface of (heat transfer layer film 81) and 815 (heat transfer layer film 86) to a thickness of 0.2 μm. The same UV curable resin as that used in Example 2 was applied to the vapor-deposited surface to a thickness of 50 nm by spin coating and cured to form a first thermal lens forming layer.
The ultraviolet curable resin layer functions as a first thermal lens forming layer and also serves to prevent the dissolution of platinum phthalocyanine. Hereinafter, an assembling optical cell is assembled in the same manner as in Example 6, and a commercially available liquid crystal ("ZLI-11" manufactured by Merck & Co., Inc.) is supplied to the liquid filling portion 818.
32 "). Thus, quartz glass (heat transfer layer film 81, film thickness 1 mm) / platinum phthalocyanine vapor-deposited film (light absorbing film 84, film thickness 0.2 μm) / liquid crystal film (thermal lens forming layer 80) / platinum phthalocyanine vapor-deposited film (light absorption film) Film 85, film thickness 0.2 μm) / quartz glass (heat transfer layer film 8)
6, a film thickness of 1 mm).

The optical response of the laminated thin-film optical element of this example was measured in the same manner as in Example 1, and the same high-speed optical response as in Example 1 was observed.

Example 8 A glass plate (24 mm × 30 m)
m × 0.15 mm) as a heat insulating layer by spin coating a dichloromethane solution of polycarbonate resin,
Coating to a thickness of 0.1 μm after drying, 10 ^-4 Pa
In the following high-vacuum container, a material was used which had been degassed in a temperature range of 100 ° C. to 120 ° C. for 48 hours, and platinum phthalocyanine was vacuum-deposited on the surface of the heat insulating layer so as to have a thickness of 0.2 μm. . Example 1 except that this was used
In the same manner as in the case of
0 μm) / polycarbonate resin layer (heat insulating layer, film thickness of 0.
1 μm) / Platinum phthalocyanine evaporated film (light absorbing film 8)
4, film thickness 0.2 μm) / polycarbonate resin layer (thermal lens forming layer 80, film thickness 20 μm) / platinum phthalocyanine deposited film (light absorbing film 85, film thickness 0.2 μm) / polycarbonate resin layer (heat insulation layer, film thickness) A multilayer thin-film optical element having a structure of 0.1 μm) / glass (heat transfer layer film 86, film thickness 150 μm) was prepared.

The optical response of the laminated thin-film optical element of this example was measured in the same manner as in Example 1, and a high-speed optical response equivalent to or higher than that of Example 1 was observed. That is, the signal light intensity changes up to a high-speed “bright” pulse with a control light ON time of 100 nanoseconds and a light-off time of 900 nanoseconds and a high-speed “dark” pulse with a control light ON time of 900 nanoseconds and a light-off time of 100 nanoseconds. It was confirmed that it would follow.

[0189]

As described above in detail, according to the laminated thin film optical element, the light control method and the light control device of the present invention, for example, a low power laser light in a visible region is used as control light. It is possible to accurately modulate signal light in the near-infrared region with a very simple optical device at a submicrosecond response speed without using any electronic circuit or the like. Further, the optical axes of the control light and the signal light can be easily adjusted, and a very compact light control device can be provided.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration example of a laminated thin-film optical element of the present invention.

FIG. 2 is a configuration diagram illustrating a device configuration used when embodying the present invention;

FIG. 3 is a configuration diagram illustrating a device configuration used when embodying the present invention;

FIG. 4 is a configuration diagram illustrating a device configuration used when embodying the present invention;

FIG. 5 is a configuration diagram illustrating a device configuration used when embodying the present invention;

FIG. 6 is a scanning electron micrograph of the surface of a platinum phthalocyanine vapor-deposited film.

FIG. 7 shows a laminated thin-film optical element of Example 1 and Comparative Example 1
3 is a transmittance spectrum of the light absorbing film single layer / thermal lens forming layer single layer / laminated thin film optical element of FIG.

FIG. 8 is a schematic diagram showing a state near a focal point of a Gaussian beam converged by a condenser lens or the like.

FIG. 9 is a diagram exemplifying a change over time in light intensity of control light and signal light when a minimum convergent beam diameter position is set near a condenser lens of a thin film optical element.

FIG. 10 is a diagram exemplifying a change over time in light intensity of control light and signal light when a minimum convergent beam diameter position is set near a light receiving lens of a thin film optical element.

FIG. 11 is an assembled liquid cell 81 used in Embodiment 6.
It is the schematic diagram which illustrated the component of No. 0.

[Explanation of symbols]

1 light source for control light, 2 light source for signal light, 3 ND filter, 4 shutter, 5 transflective mirror, 6 optical mixer,
7 condensing lens, 8 laminated thin-film optical element, 9 light receiving lens, 11 photodetector (for detecting light intensity of control light), 20
Wavelength selective transmission filter (for blocking control light), 22 photodetector (for detecting light intensity of signal light), 70 and 90 refractive index distribution type lens, 80 thermal lens forming layer, 81 and 86
Heat transfer layer film, 82 and 89 light transmission layer, 83 heat insulation layer film, 84 and 85 light absorption film, 100 oscilloscope, 111 signal from light detector 11 (light intensity time change curve of control light), 222 and 223 light 121. Signal from light detector 22 (light intensity time change curve of signal light), 121: transmittance spectrum curve of laminated thin film optical element of Example 1, 1
22 Single Layer of Light Absorbing Film of Comparative Example 1 / Single Layer of Thermal Lens Forming Layer
Transmittance spectrum curve of laminated thin film optical element, 810 assembled optical cell, 811 fixed frame, 812 rubber packing, 813 entrance / exit surface glass, 814 spacer, 815 entrance / exit surface glass (with inlet hole), 816
Rubber packing (with introduction hole), 817 Fixed frame (with introduction tube), 818 Liquid filling part (thermal lens forming layer), 819
Introducing hole, 820 Introducing hole, 821 Introducing hole, 822
Introduction pipe, 823 Introduction pipe, 824 fixing screw hole, 825
When the light level of the signal light is turned on and the B focus Fc is set on the condenser lens 7 side of the stacked thin film optical element 8 when the light source of the signal light is turned on while the control light is blocked. And the output level of the photodetector 22 when the control light is irradiated with the light source of the signal light turned on, the output level of the photodetector 22 with the signal light turned off, and the D focus Fc are the laminated thin film. The output level of the photodetector 22 when it is set on the light receiving lens 9 side of the optical element 8 and when the control light is irradiated with the signal light source turned on, the _d78 condenser lens 7 and the laminated thin film distance of the optical device 8, the distance of the light receiving lens 9 and d ₈₉ stacked thin film optical element 8, Fc focus, S1
The time when the light sources of the control light, the S2 signal light, and the t1 signal light were turned on, the time when the shutter that blocked the t2 control light was opened, the time when the t3 control light was blocked again by the shutter, and the shutter that blocked the t4 control light were switched off. Time when it was released, t5 Time when the control light was shut off again by the shutter, t5
6 The time when the light source of the signal light is turned off, the angle between the outer circumference of the light beam converged by the θ focusing lens and the optical axis, the beam waist of the Gaussian beam focused by the ω ₀ focusing lens (beam radius at the focal position) ), Zc confocal distance.

 ──────────────────────────────────────────────────続 き Continued on the front page (74) The above two agents 100075258 Patent Attorney Kenji Yoshida (two outsiders) (72) The inventor Takashi Hiraga 1-4-1 Umezono, Tsukuba, Ibaraki Pref. Within the research institute (72) Kuniei Chen 1-1-4 Umezono, Tsukuba-city, Ibaraki Pref. Inside the Electrotechnical Laboratory (72) Norio Tanaka, Inventor 1-7-6 Nibashi Bakurocho, Chuo-ku, Tokyo Inside Dainichi Seika Kogyo Co., Ltd. (72) Hiromitsu Yanagimoto 1-7-6 Nihonbashi Bakurocho, Chuo-ku, Tokyo (72) Inventor Ichiro Ueno 3-12-12 Moriyacho, Kanagawa-ku, Yokohama-shi, Kanagawa Prefecture Inside of Victor Company of Japan (72) Who Koji Tsujita Yokohama-shi, Kanagawa, Kanagawa-ku, Moriya-cho 3-chome 12th place Victor Company of Japan, Ltd. in

Claims (26)

[Claims] 1. A light absorbing layer in a laminated thin-film optical element including at least a light absorbing layer is irradiated with converging control light and signal light having different wavelengths from each other, and the wavelength of the control light is the light absorbing layer. Is selected from the wavelength band in which the control light is focused, at least the control light is focused in the light absorption layer, and the light absorption layer is reversible due to a temperature rise occurring in a region where the control light is absorbed and the surrounding region. A thin-film optical element for performing intensity modulation and / or luminous flux density modulation of the signal light by using a thermal lens based on a distribution of a refractive index generated in the light-absorbing layer, wherein the light-absorbing layer is a three-layer thin film; The first layer is a light absorbing film that absorbs light in the wavelength band of the control light, and the second layer is a thermal lens forming layer that is light transmissive in the wavelength band of the control light and the signal light. The first Layers stacked thin film optical element which is a light-absorbing layer that absorbs light in the wavelength band of the control light. 2. The laminated thin-film optical element according to claim 1, wherein, of the two light absorbing films sandwiching the thermal lens forming layer, the light absorbing film on the control light incident side receives the control light. A laminate wherein the transmittance of the control light wavelength band is adjusted so that 10 to 90% is absorbed, and the light absorbing film on the control light emission side absorbs the remainder of the control light. Type thin film optical element. 3. The laminated thin-film optical element according to claim 1, wherein a thickness of the light-absorbing layer formed of the laminated thin film does not exceed twice a confocal distance of the converged control light. Characteristic laminated thin-film optical element. 4. The laminated thin-film optical element according to claim 2, wherein a thickness of the light-absorbing layer formed of the laminated thin film does not exceed twice a confocal distance of the converged control light. Characteristic laminated thin-film optical element. 5. The laminated thin-film optical element according to claim 1, wherein the light-absorbing layer made of the laminated thin film further has a light transmittance in a wavelength band of the control light and the signal light. And / or a heat transfer layer film that is light-transmissive in the wavelength band of the control light and the signal light, and laminated with a configuration selected from the following groups (a) to (i). Characteristic laminated thin-film optical element. (A) Light absorption layer / heat insulation layer film (b) Heat insulation layer film / light absorption layer / heat insulation layer film (c) Light absorption layer / heat transfer layer film (d) Heat transfer layer film / light absorption layer / heat transfer layer Film (e) Light absorption layer / heat insulation layer / heat transfer layer film (f) Heat transfer layer film / light absorption layer / heat insulation layer film (g) Heat transfer layer film / light absorption layer / heat insulation layer film / heat transfer layer Film (h) Heat transfer layer film / heat insulation layer film / light absorption layer / heat insulation layer film (i) Heat transfer layer film / heat insulation layer film / light absorption layer / heat insulation layer film / heat transfer layer film 6. The laminated thin-film optical element according to claim 5, wherein the refractive index distribution type lens as a converging means for the control light and the signal light comprises: a light absorption layer on the signal light incident side; A laminated thin-film optical element, which is provided by being laminated on a layer film or a heat transfer layer film directly or further via a light transmitting layer. 7. The laminated thin-film optical element according to claim 5, wherein a signal light beam diverging after passing through the light absorbing layer has an angle range smaller than a divergence angle of the signal light beam. A gradient index lens as a means for separating and extracting a signal light beam in a region that has been strongly subjected to intensity modulation and / or light flux density modulation by extracting the light absorption layer on the signal light emission side, or A laminated thin-film optical element which is provided by being laminated on a heat insulating layer film or a heat transfer layer film directly or via a light transmitting layer. 8. The laminated thin-film optical element according to claim 6, wherein the signal light beam diverging after passing through the light absorbing layer has an angle range smaller than the divergence angle of the signal light beam. A gradient index lens as a means for separating and extracting a signal light beam in a region that has been strongly subjected to intensity modulation and / or light flux density modulation by extracting the light absorption layer on the signal light emission side, or A central axis of each lens, facing the refractive index distribution type lens provided on the signal light incident side of the light absorption layer, directly or through a light transmission layer, on the heat insulation layer film or the heat transfer layer film. A stacked thin-film optical element characterized by being provided in a stacked manner. 9. The laminated thin-film optical element according to claim 1, wherein the light-absorbing film contains a dye that absorbs light in the control light wavelength band. Stacked thin film optical element. 10. The laminated thin-film optical element according to claim 1, wherein the light-absorbing film is made of an amorphous aggregate of a dye that absorbs light in the control light wavelength band. Characteristic laminated thin-film optical element. 11. The laminated thin-film optical element according to claim 1, wherein the light-absorbing film is made of a fine crystal aggregate of a dye that absorbs light in the control light wavelength band, and A laminated thin-film optical element, wherein the particle diameter of the dye microcrystals does not exceed 1/5 of the shorter wavelength of the signal light and the control light. 12. The laminated thin-film optical element according to claim 1, wherein the thermal lens forming layer is selected from the group consisting of an amorphous organic compound, an organic compound liquid, and a liquid crystal. A laminated thin-film optical element comprising a compound. 13. The control light, wherein the control light and the signal light having different wavelengths are respectively converged and applied to the light absorbing layer, using the laminated thin film optical element according to claim 1. Is selected from the wavelength band that the light absorbing layer absorbs, at least the control light is focused within the light absorbing layer, and the light absorbing layer has a temperature that occurs in a region where the control light is absorbed and a peripheral region thereof. A light control method, wherein intensity modulation and / or luminous flux density modulation of the signal light is performed by using a thermal lens based on a refractive index distribution reversibly generated due to the rise. 14. The control light and the signal light are respectively applied to the refractive index distribution type lens provided on the control light and the signal light incident side using the laminated thin film optical element according to claim 6. At least the control light is focused in the light absorbing layer, and is based on a refractive index distribution reversibly generated due to a temperature rise occurring in a region where the light absorbing layer absorbs the control light and a peripheral region thereof. A light control method for performing intensity modulation and / or light flux density modulation of the signal light by using a thermal lens. 15. The laminated thin-film optical element according to claim 7, wherein control light and signal light having different wavelengths are respectively converged and irradiated to the light absorbing layer, and the wavelength of the control light is the light. Selected from the wavelength band absorbed by the absorption layer, at least the control light is focused within the light absorption layer, and the light absorption layer is caused by a temperature rise occurring in the region where the control light is absorbed and the peripheral region thereof. A light control method comprising performing intensity modulation and / or light flux density modulation of the signal light by using a thermal lens based on a reversible refractive index distribution. 16. The control light and the signal light are respectively applied to the refractive index distribution type lens provided on the control light and the signal light incident side using the laminated thin film optical element according to claim 8. At least the control light is focused in the light absorbing layer, and is based on a refractive index distribution reversibly generated due to a temperature rise occurring in a region where the light absorbing layer absorbs the control light and a peripheral region thereof. A light control method, wherein intensity modulation and / or light flux density modulation of the signal light is performed by using a thermal lens. 17. The light control method according to claim 13, wherein a signal light beam diverging after passing through the laminated thin-film optical element has an angle range smaller than a divergence angle of the signal light beam. A light control method characterized by separating and extracting a signal light beam in a region that has been strongly subjected to intensity modulation and / or light density modulation by extracting the light beam. 18. The light control method according to claim 14, wherein the signal light beam diverging after passing through the laminated thin-film optical element has an angle range smaller than the divergence angle of the signal light beam. A light control method characterized by separating and extracting a signal light beam in a region that has been strongly subjected to intensity modulation and / or light density modulation by extracting the light beam. 19. The light control method according to claim 15, wherein the light is transmitted through the light absorption layer by using the refractive index distribution type lens provided on the signal light emission side of the light absorption layer. Thereafter, by extracting the diverging signal light beam in an angle range smaller than the divergence angle of the signal light beam, the signal light beam in an area which has been strongly subjected to intensity modulation and / or light density modulation is separated. A light control method characterized by taking out separately. 20. The light control method according to claim 16, wherein the light is transmitted through the light absorption layer using the refractive index distribution type lens provided on the signal light emission side of the light absorption layer. Thereafter, by extracting the diverging signal light beam in an angle range smaller than the divergence angle of the signal light beam, the signal light beam in an area which has been strongly subjected to intensity modulation and / or light density modulation is separated. A light control method characterized by taking out separately. 21. The laminated thin film optical element according to claim 1, wherein the light absorbing layer is irradiated with control light and signal light having different wavelengths, respectively, and the wavelength of the control light is The light absorbing layer is selected from a wavelength band absorbed by the light absorbing layer, and the light absorbing layer includes a thermal lens based on a refractive index distribution that reversibly occurs due to a temperature rise occurring in a region absorbing the control light and a peripheral region thereof. By using this, intensity modulation of the signal light and / or
Or a light control device that performs light flux density modulation, further comprising convergence means for converging the control light and the signal light, respectively, wherein the converged control light and the signal light have the highest photon density in the vicinity of their respective focal points. The optical paths of the control light and the signal light are respectively arranged such that the high regions overlap with each other, and the light absorption layer of the laminated thin-film optical element includes the converged control light and the signal light, respectively. A light control device characterized in that regions having the highest photon density near the focal point are arranged at positions overlapping each other. 22. The control light and the signal light are respectively applied to the refractive index distribution type lens provided on the control light and the signal light incident side, using the laminated thin film optical element according to claim 6. At least the control light is focused in the light absorbing layer, and is based on a refractive index distribution reversibly generated due to a temperature rise occurring in a region where the light absorbing layer absorbs the control light and a peripheral region thereof. A light control device that performs intensity modulation and / or light flux density modulation of the signal light by using a thermal lens, wherein the control light and the signal light serve as converging means for converging the control light and the signal light, respectively. Having the gradient index lens provided on the incident side, areas where the converged control light and the signal light have the highest photon densities near the respective focal points overlap each other. As described above, the optical paths of the control light and the signal light are respectively arranged, and the light absorption layer of the thin-film optical element has the highest photon density near the focal point of each of the converged control light and the signal light. A light control device, wherein the regions are arranged at positions overlapping each other. 23. The light control device according to claim 21, wherein as means for separating and extracting a signal light beam in a region which has been strongly subjected to intensity modulation and / or light beam density modulation,
A light control device comprising means for extracting a signal light beam diverging after passing through the thin film optical element in an angle range smaller than the divergence angle of the signal light beam. 24. The light control device according to claim 22, wherein as means for separating and extracting a signal light beam in a region which has been strongly subjected to intensity modulation and / or light beam density modulation,
A light control device comprising means for extracting a signal light beam diverging after passing through the thin film optical element in an angle range smaller than the divergence angle of the signal light beam. 25. The laminated thin-film optical element according to claim 7, wherein the light absorbing layer is irradiated with control light and signal light having different wavelengths, respectively, and the wavelength of the control light is controlled by the light absorbing layer. It is selected from a wavelength band that absorbs, the light absorbing layer uses a thermal lens based on a refractive index distribution that reversibly occurs due to a temperature rise that occurs in a region that absorbs the control light and a peripheral region thereof. Signal light intensity modulation and / or
Or a light control device that performs light flux density modulation, further comprising convergence means for converging the control light and the signal light, respectively, wherein the converged control light and the signal light have the highest photon density in the vicinity of their respective focal points. The optical paths of the control light and the signal light are respectively arranged such that the high regions overlap with each other, and the light absorption layer of the laminated thin-film optical element includes the converged control light and the signal light, respectively. The regions having the highest photon densities near the focal point are arranged at positions overlapping each other, and further, the signal light flux that diverges after passing through the light absorbing layer is formed at an angle smaller than the divergence angle of the signal light flux. As a means for separating and extracting a signal light beam in an area which has been strongly subjected to intensity modulation and / or light flux density modulation by extracting in the range, the signal of the light absorbing layer is used. Light control device characterized by having a gradient index lens that is provided on the emission side. 26. The control light and the signal light are respectively applied to the refractive index distribution type lens provided on the control light and the signal light incident side using the laminated thin film optical element according to claim 8. At least the control light is focused in the light absorbing layer, and is based on a refractive index distribution reversibly generated due to a temperature rise occurring in a region where the light absorbing layer absorbs the control light and a peripheral region thereof. A light control device that performs intensity modulation and / or light flux density modulation of the signal light by using a thermal lens, wherein the control light and the signal light serve as converging means for converging the control light and the signal light, respectively. Having the gradient index lens provided on the incident side, areas where the converged control light and the signal light have the highest photon densities near the respective focal points overlap each other. As described above, the optical paths of the control light and the signal light are respectively arranged, and the light absorption layer of the stacked thin film optical element has a photon density near the focal point of each of the converged control light and the signal light. The highest areas are arranged at positions overlapping each other, and further, a signal light beam diverging after passing through the laminated thin film optical element is extracted in an angle range smaller than the divergence angle of the signal light beam. Means for separating and extracting a signal light beam in a region which has been strongly subjected to intensity modulation and / or light beam density modulation by the refractive index distribution type lens provided on the signal light emission side of the light absorbing layer. A light control device characterized by the above-mentioned.