CN205450432U - Super diffraction limit's structured light lighting device , optics template and optical system - Google Patents

Abstract

The utility model is applicable to the field of optics, and discloses a structured light lighting device with super-diffraction limit. Multiple linear light-transmitting regions of structured light with super-diffraction limit are formed at the focal plane of the lens. The linear light-transmitting regions are arranged side by side and have different transmittances and thicknesses. The multiple linear light-transmitting regions are symmetrical about the central axis of the optical template. The super-diffraction-limited structured light is formed in the middle of the focal plane of the lens and presents a sinusoidal superoscillating grating-like intensity distribution, and the frequency of the super-diffraction-limited structured light is greater than the spatial frequency corresponding to the diffraction limit of the system. The spatial frequency of the super-diffraction limit structured light of the utility model is greater than the corresponding spatial frequency of the system diffraction limit, which breaks through the bottleneck that the highest resolution of the traditional structured light illumination is only half of the diffraction limit, and has important significance for the structured light microscopic imaging .

Description

Super-diffraction-limited structured light illumination device, optical template and optical system

technical field

The utility model belongs to the field of optical information technology, and in particular relates to a super-diffraction limit structured light illuminating device, an optical template and an optical system.

Background technique

At present, information technology has entered the nanometer era, in which the development of nano-optics and photonics is particularly important, for example, in information technologies such as nano-lithography, nano-imaging and nano-information storage, all of which have very important applications. However, the minimum feature size and processing resolution of nano-optical and photonic devices, as well as the resolution of optical microscopy imaging, are limited by the diffraction limit of light. According to the diffraction limit theory proposed by Abbe, what people can do now is to try to use shorter wavelength light and an optical system with larger numerical aperture, but now it seems that the wavelength and numerical aperture have basically reached the limit, and it is still not enough The needs of the development of information technology. Therefore, research to break through the diffraction limit is very necessary. The U.S. Congress proposed in 2009 that the first of the five major research projects in optics in the 21st century is to break through the diffraction limit. It is also mentioned in the 100 scientific problems of the 21st century listed in "Nature". Regarding the issue of super-resolution, the Chinese Academy of Sciences also proposed in 2011 that my country should strengthen research on super-resolution technology. For more than a century, scientists have been working hard to surpass the diffraction limit, and many super-resolution methods have been produced.

Structured illumination microscopic imaging is one of the widely used methods at present, and it can easily realize wide-field high-spatial resolution imaging, but the resolution limit of this method is half of the diffraction limit of the optical system (under non-saturated conditions), which is A bottleneck has been hindering the further development of the method. Therefore, a new technical solution is needed to solve the above problems.

Utility model content

The purpose of the utility model is to provide a super-diffraction limit structured light lighting device, which aims to obtain super-diffraction structured light, break through the resolution limit of structured light imaging, and improve the resolution of the optical system.

The utility model is achieved in this way, a structured light lighting device with super diffraction limit, including an optical template and a lens, the distance between the optical template and the lens is equal to the focal length of the lens, and the optical template is provided with a plurality of Linear light-transmitting regions with different transmittances and different thicknesses arranged side by side, a plurality of linear light-transmitting regions are symmetrically distributed with respect to the central axis of the optical template parallel to the linear light-transmitting regions, and parallel light passes through the optical The first transmitted light is formed after the template, and the first transmitted light forms the second transmitted light after passing through the lens, and the second transmitted light forms a super-diffraction-limited light in the low-energy region in the middle of the focal plane of the lens Structured light, the structured light of the super-diffraction limit presents a super-oscillating grating-like intensity distribution in a sine wave state, and the frequency of the structured light of the super-diffraction limit is greater than the spatial frequency corresponding to the diffraction limit of the system.

As the preferred technical solution of the utility model:

The Fourier spectrum components of the super-diffraction limit structured light are parts higher than the frequency corresponding to the diffraction limit of the optical system.

The minimum characteristic size of the super-diffraction-limited structured light is smaller than the diffraction limit of the optical system.

The optical template is a modulation plate of amplitude and phase.

The surface of the amplitude-plus-phase modulation plate is provided with a linear coating for forming the linear light-transmitting region.

The period of the super-diffraction-limited structured light is affected by the amplitude and phase modulation ratio of the linear light-transmitting region.

The parallel light is monochromatic light or quasi-monochromatic light.

Another object of the present utility model is to provide an optical template, which is used to combine with a lens to form a super-diffraction-limited structured light illumination device, the distance between the optical template and the lens is equal to the focal length of the lens, and the optical template There are multiple linear light-transmitting areas that can adjust the parallel light to form super-diffraction-limited structured light at the focal plane of the lens after passing through the lens, and the multiple linear light-transmitting areas are arranged side by side and The transmittance and thickness are all different, and the multiple linear light-transmitting regions are distributed symmetrically with respect to the central axis parallel to the linear light-transmitting regions of the optical template, and the super-diffraction-limited structured light is formed on the focal plane of the lens In the middle part, and presents a super-oscillating grating-like intensity distribution in a sine wave state, the frequency of the structured light in the super-diffraction limit is greater than the spatial frequency corresponding to the diffraction limit of the system.

Another object of the present utility model is to provide an optical system, including the above-mentioned super-diffraction limit structured light illumination device.

The super-diffraction limit structured light lighting device provided by the utility model uses an optical template to process parallel incident light, and makes it undergo Fourier transform through the lens, and generates a super-diffraction limit sine wave form in the middle area of the focal plane of the lens Structured light whose spatial frequency is greater than the spatial frequency corresponding to the diffraction limit of the system, so that when the structured light is used for microscopic imaging under structured light, the imaging resolution limit can be smaller than the diffraction limit of the system under the same conditions Half of that, breaking through the bottleneck that the highest resolution is only half of the diffraction limit under traditional structured light illumination, it is of great significance for structured light microscopic imaging.

Description of drawings

Fig. 1 is a structural schematic diagram of a super-diffraction limit structured light illumination device provided by an embodiment of the present invention;

Fig. 2 is a schematic structural view of the optical template of the super-diffraction limit structured light illumination device provided by the embodiment of the present invention;

Fig. 3 is a schematic diagram of moiré fringes provided by the embodiment of the present invention;

Fig. 4 is the vector relationship between the spatial frequency k contained in the sample provided by the embodiment of the present invention, the structured light spatial frequency k0 and the spatial frequency Km corresponding to the Moiré fringes;

Fig. 5 is an intensity distribution diagram at the focal plane of the lens provided by the embodiment of the present invention;

Fig. 6 is the spectral component of the entire waveform at the focal plane of the lens provided by the embodiment of the present invention;

FIG. 7 is a Fourier transform result diagram of the elliptical region in FIG. 5 .

detailed description

In order to make the purpose, technical solution and advantages of the utility model clearer, the utility model will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the utility model, and are not intended to limit the utility model.

Please refer to Fig. 1, the utility model provides a structured light illumination device with super diffraction limit, including an optical template 01 and a lens 02, the distance between the optical template 01 and the lens 02 is equal to the focal length f of the lens 02, as shown in Fig. 2, the optical The template 01 is provided with a plurality of linear light-transmitting regions 011 arranged side by side with different transmittances and different thicknesses. The plurality of linear light-transmitting regions 011 are distributed symmetrically about the central axis L of the optical template 01. The central axis L refers to the The central axis of the linear light-transmitting region 011 that divides the optical template 01 into two parts, the different transmittances and different thicknesses of the linear light-transmitting region 011 are used to realize the modulation of the amplitude and phase of the light, so as to change the characteristics of the incident light. The parallel light S (monochromatic or quasi-monochromatic parallel light) passes through the optical template 01 to form the first transmitted light, and the first transmitted light is transformed by the lens 02 to form the second transmitted light, and the second transmitted light The morphology at the focal plane of the lens 02 is shown in Figure 1. The low-energy region in the middle forms the super-diffraction-limited structured light S', and the super-diffraction-limited structured light presents a super-oscillating grating-like intensity in a sine wave state. Distribution, the frequency of structured light beyond the diffraction limit is greater than the spatial frequency corresponding to the diffraction limit of the system. When the super-diffraction-limited structured light is used for imaging with illumination light, its resolution can break through half of the diffraction limit of the optical system.

In this embodiment, the Fourier spectrum component of the super-diffraction-limited structured light S' is a part higher than the frequency corresponding to the diffraction limit of the optical system, the characteristic size of the super-oscillating grating and the size of the grating area can be transmitted through the design The minimum characteristic size is smaller than the diffraction limit of the optical system. The characteristic size refers to the full width at half maximum of the narrowest peak of the structured light intensity distribution. The optical system refers to the optical system based on the above-mentioned lens 02.

Further, the optical template 01 is preferably an amplitude-plus-phase modulation plate, and a linear coating for forming a linear light-transmitting region 011 is provided on its surface. The period of the super-oscillating grating is affected by the amplitude and phase modulation ratio of the linear light-transmitting region 011 . The multiple linear coatings are divided into two parts with the same structure and characteristics, and the two parts are left-right symmetrical, and each linear coating corresponds to a frequency band.

The working principle of the device will be further described in conjunction with the accompanying drawings. The optical wavelength and the system numerical aperture determine the spatial frequency bandwidth that can pass through the system, that is, in any ordinary optical system, the spatial frequency components higher than the frequency limit will be eliminated. system filtering out, resulting in limited resolution of the imaging system. In the microscopic imaging method of structured illumination, it is precisely because of this that the minimum resolvable size of structured light is limited, making the resolution limit of this imaging method half of the diffraction limit of ordinary imaging systems.

Structured illumination microscopic imaging itself can improve the lateral spatial resolution, and its principle can be explained by the Moiré effect. For example, a certain spatial frequency k (represented by grating fringes) contained in the sample will produce a moiré effect under the illumination condition of structured light with frequency k0, that is, moiré fringes as shown in FIG. 3 . The vector relationship between them can be shown in Figure 4. Km represents the spatial frequency corresponding to the Moiré fringe. Since both the illumination optical path and the imaging optical path are limited by the diffraction limit of the system (corresponding to the spatial frequency kmax), that is, k0<=kmax, km<= kmax, so the maximum value of the spatial frequency k is 2kmax, which means that the highest resolution can reach half of the diffraction limit. The super-diffraction-limited structured light is used for illumination, which is to realize k0>kmax locally, so that the spatial frequency k can be greater than 2kmax, that is, the resolution limit can be less than half of the diffraction limit.

The device of this embodiment is such a super-diffraction-limited structured light illumination device, which utilizes the super-oscillation phenomenon. The so-called super-oscillation means that the band-limited function can oscillate arbitrarily fast in any large interval, and the local frequency exceeds its maximum The Fourier transform component, that is, the above k0>kmax, the device can obtain the structured light with k0>kmax, that is, the structured light of the super-diffraction limit, and the structured light is different from the traditional structured light involving super oscillation. The super-oscillating waveform designed by the zero-point optimization method is shown in Figure 5. Figure 5 shows the intensity distribution of the super-diffraction-limited structured light. In the elliptical region, the distances between the zero points are equal. When the values of the peaks are approximately equal, this local waveform can be regarded as a sinusoidal waveform, and this The waveform has a super-diffraction structure, and its minimum feature size is smaller than the diffraction limit of the optical system, which can be called a super-oscillating grating. Of course, the waveform may not be a strictly sinusoidal waveform, but a shape very close to a sinusoidal waveform, which can be called a "quasi-sine wave". The limiting resolution of traditional structured light imaging is half of the diffraction limit. The main reason is that both the receiving optical path and the illuminating optical path are limited by the diffraction limit. Using the super-diffraction-limited structured light illumination can break through the minimum resolvable size limit of structured light, and also That is, the resolution limit can be less than half of the diffraction limit.

Figure 5 shows the intensity distribution diagram at the focal plane of the lens 02. In the oval area is a sinusoidal waveform (a certain frequency in its Fourier spectrum is the main component), and this waveform has a super-diffraction structure, that is, it The main frequency components of are larger than the kmax mentioned above. Figure 6 shows the spectral components of the entire waveform at the focal plane of the lens 02, where the dotted lines on both sides indicate the highest frequency determined by the diffraction limit. Figure 7 is the result of Fourier transform performed on the elliptical area alone. The solid line represents the frequency corresponding to the equivalent super-oscillating grating. Figure 7 proves that the waveform in the elliptical area is indeed super-diffraction limited, and a certain frequency occupies the The principal components of quasi-sine light. The super-diffraction-limited structured light can be used for structured light microscopy imaging, and the resolution limit can be less than half of the diffraction limit.

The super-diffraction limit structured light illumination device provided by the embodiment of the present invention uses the optical template 01 to process the parallel incident light, and makes it undergo Fourier transform through the lens 02 to generate super-diffraction in the middle area of the focal plane of the lens 02 The structured light in the form of a limit sine wave, the spatial frequency of the structured light is greater than the corresponding spatial frequency of the system diffraction limit, so that when the structured light is used for the microscopic imaging of the structured light, under the same conditions, the imaging resolution limit It can be less than half of the diffraction limit of the system, which breaks through the bottleneck that the highest resolution of traditional structured light illumination is only half of the diffraction limit, and because it is sinusoidal or quasi-sinusoidal, there is no strong side lobe, so that the optical system can receive It has better dynamic range and signal-to-noise ratio.

The optical template 01 used in the embodiment of the present invention is the main optical component for generating super-diffraction-limited structured light, and the optical template 01 with the above-mentioned structural and optical features is also within the protection scope of the present invention. Further, the optical system adopting the above-mentioned structured light illuminating device with super-diffraction limit is also within the protection scope of the present invention.

The utility model further provides a method for obtaining super-diffraction-limited structured light, which includes the following steps:

Firstly, let the parallel light pass through the optical template 01 to form the first transmitted light. The optical template 01 has the structure of the above-mentioned optical template 01, that is, there are a plurality of linear light-transmitting regions 011 arranged side by side with different transmittances and different thicknesses. , a plurality of linear light-transmitting regions 011 are distributed symmetrically with respect to the central axis of the optical template 01 parallel to the linear light-transmitting regions 011;

Then, let the first transmitted light pass through the lens 02 with one focal length from the optical template 01 to form the second transmitted light, and the second transmitted light forms super-diffraction-limited structured light in the middle of the focal plane of the lens 02, and the super-diffraction limit The light intensity distribution of the structured light presents a super-oscillating grating-like intensity distribution in a sine wave state, and the frequency of the structured light at the super-diffraction limit is greater than the spatial frequency corresponding to the diffraction limit of the system.

In this embodiment, the area size of the super-diffraction-limit structured light determines the field of view of the final structured light imaging, which can be adjusted according to actual requirements.

This method is implemented based on the super-diffraction-limit structured light illumination device provided by the present invention, and its principle and effect are the same as those described above, and will not be repeated in this embodiment.

The above are only preferred embodiments of the present utility model, and are not intended to limit the present utility model. Any modifications, equivalent replacements or improvements made within the spirit and principles of the present utility model should be included in the utility model. within the scope of protection.

Claims (9)

1. the Structured Illumination device of a super diffraction limit, it is characterized in that, including optics template and lens, the spacing of described optics template and described lens is equal to the focal length of described lens, described optics template is provided with and can be adjusted directional light making it form the multiple linear transparent area of the structure light of super diffraction limit after described lens at the focal plane of described lens, the plurality of linear transparent area laid out in parallel and transmitance and thickness are the most different, multiple described linear transparent areas are symmetrical about the axis being parallel to linear transparent area of described optics template, the structure light of described super diffraction limit is formed at the middle part at the focal plane of described lens, and it is rendered as the hyperoscillating raster-like intensity distributions of sinusoidal wave state, the spatial frequency that the frequency of the structure light of described super diffraction limit is corresponding more than system diffraction limit.

2. the Structured Illumination device of super diffraction limit as claimed in claim 1, it is characterised in that the Fourier spectrum composition of the structure light of described super diffraction limit is the part higher than optical system diffraction limit respective frequencies.

3. the Structured Illumination device of super diffraction limit as claimed in claim 1, it is characterised in that the minimum feature size of the structure light of described super diffraction limit is less than the diffraction limit of optical system.

4. the Structured Illumination device of super diffraction limit as claimed in claim 1, it is characterised in that described optics template is the modulation panel that amplitude adds phase place.

5. the Structured Illumination device of super diffraction limit as claimed in claim 4, it is characterised in that the surface of the modulation panel that described amplitude adds phase place is provided with the linear plated film for forming described linear transparent area.

6. the Structured Illumination device of super diffraction limit as claimed in claim 1, it is characterised in that the cycle of the structure light of described super diffraction limit is by the amplitude of described linear transparent area and phase-modulation scale effect.

7. the Structured Illumination device of super diffraction limit as claimed in claim 1, it is characterised in that described directional light is monochromatic light or quasi-monochromatic light.

8. an optics template, it is characterized in that, for constituting the Structured Illumination device of super diffraction limit with lens combination, the spacing of described optics template and described lens is equal to the focal length of described lens, described optics template is provided with and can be adjusted directional light making it form the multiple linear transparent area of the structure light of super diffraction limit after described lens at the focal plane of described lens, the plurality of linear transparent area laid out in parallel and transmitance and thickness are the most different, multiple described linear transparent areas are symmetrical about the axis being parallel to linear transparent area of described optics template, the structure light of described super diffraction limit is formed at the middle part at the focal plane of described lens, and it is rendered as the hyperoscillating raster-like intensity distributions of sinusoidal wave state, the spatial frequency that the frequency of the structure light of described super diffraction limit is corresponding more than system diffraction limit.

9. an optical system, it is characterised in that include the Structured Illumination device of super diffraction limit described in any one of claim 1～8.