CN118409408A - Super surface and near infrared imaging system with same - Google Patents

Abstract

The invention provides a super surface and a near infrared imaging system with the same, wherein the super surface comprises a plurality of super structure units which are arrayed, the super surface is provided with a first area and a second area, the centers of the first area and the second area are mutually overlapped, the first area is closer to the center than the second area, the radial period of the super structure units in the second area is smaller than the radial period of the super structure units in the first area, and/or the circumferential period of the super structure units in the second area is smaller than the circumferential period of the super structure units in the first area; the radial period and/or the circumferential period of the super-structure units are distributed in a variable period mode, so that the super-structure units in the second area have better modulation effect on incident light with a large angle, are suitable for a large Numerical Aperture (NA) system and a wide-angle imaging scene, and can improve the efficiency of the large NA system or the wide-angle imaging quality.

Description

Super surface and near infrared imaging system with same

Technical Field

The invention relates to the technical field of optical lenses, in particular to a super-surface.

Background

The super-structure unit period of the super-surface mostly adopts a constant period, the phase regulation mechanism is generally based on normal incidence or small-angle incidence, the consideration of the optical performance under large-angle oblique incidence is less, the light under large-angle incidence needs to be considered in the fields of wide-angle imaging and the like, at the moment, the problem of imaging quality reduction of the super-surface, such as phase mutation, occurs, and the super-surface is not suitable for a scene under large-angle incidence.

Disclosure of Invention

The invention aims to provide a super surface suitable for a wide-angle imaging scene and a near infrared imaging system with the super surface.

To achieve one of the above objects, an embodiment of the present invention provides a super surface including a plurality of super-structure units arranged in an array, the super surface having a first region and a second region in which the super-structure units are arranged, a center of the first region and a center of the second region being coincident with each other, the first region being closer to the center than the second region, a radial period of the super-structure units in the second region corresponding to less than a radial period of the super-structure units in the first region, and/or a circumferential period of the super-structure units in the second region corresponding to less than a circumferential period of the super-structure units in the first region.

As a further improvement of one embodiment of the present invention, the radial period of each super-structure unit decreases in the direction from the first region to the second region, and the circumferential period of each super-structure unit is equal.

As a further improvement of an embodiment of the invention, the radial period and the circumferential period of each super-structure unit decreases in a direction from the first region to the second region.

As a further improvement of an embodiment of the present invention, the super surface further has a third area in which the super structural units are arranged, the centers of the circles of the first area, the third area and the second area are mutually coincident, the outer diameter sizes are sequentially increased, and the radial period and/or the circumferential period of the super structural units in the third area is decreased from the first area to the second area.

As a further development of an embodiment of the invention, the radial and circumferential period of the superstructure units in the first zone and/or in the second zone remain unchanged.

As a further development of an embodiment of the invention, the radial period and/or the circumferential period of the superstructure units in the third zone decreases in equal proportion from the first zone to the second zone.

As a further improvement of an embodiment of the present invention, the third region has a first region, a second region and a third region with sequentially increasing outer diameter sizes, the radial period and/or circumferential period of the super-structure units in the first region decreasing in equal proportion from the first region to the second region, the radial period and/or circumferential period of the super-structure units in the second region decreasing in equal proportion from the first region to the third region, and the radial period and/or circumferential period of the super-structure units in the third region decreasing in equal proportion from the second region to the second region.

As a further refinement of an embodiment of the invention, the center and/or the vertex position of each superstructure unit is provided with nanostructures configured as polarization dependent structures or polarization independent structures.

As a further improvement of an embodiment of the present invention, the super surface further includes a substrate connecting the nanostructure, a filler connecting the nanostructure and the substrate, and an antireflection film disposed on the substrate and/or the filler, wherein the antireflection film includes a first material layer and a second material layer, and the first material layer or the second material layer is connected to the super surface.

To achieve the above object, the present invention also provides a near infrared imaging system including a super surface as described above.

Compared with the prior art, in the embodiment of the invention, the radial period and/or the circumferential period of the super-structure units are distributed in a variable period mode, and the period of the super-structure units in the second area is correspondingly smaller than that of the super-structure units in the first area, so that the super-structure units in the second area have better modulation effect on incident light with a large angle, are suitable for a large Numerical Aperture (NA) system and a wide-angle imaging scene, and can improve the efficiency or the wide-angle imaging quality of the large NA system.

Drawings

FIG. 1 is a schematic view of an optical path and a top view of a subsurface in an application scenario of the subsurface of the present invention;

FIG. 2 is a schematic view of an optical path and a top view of a subsurface in another application scenario of the subsurface of the present invention;

FIG. 3 is a schematic view of an optical path and a top view of a subsurface in yet another application scenario of the subsurface of the present invention;

FIG. 4 is a top view of a subsurface in a preferred embodiment of the invention;

FIG. 5 is a top view of a subsurface in another preferred embodiment of the invention;

FIG. 6 is a graph of the efficiency of the subsurface of FIGS. 4 and 5 at different angles of incidence;

FIG. 7 is a schematic view of the optical path at the subsurface of FIG. 1;

FIG. 8 is an embodiment of a cross-sectional view at A in FIG. 7;

FIG. 9 is another embodiment of a cross-sectional view at A in FIG. 7;

FIG. 10 is a graph of the efficiency of the subsurface of FIG. 1 at different angles of incidence;

FIG. 11 is a Bai Bingjiao plane view of a fixed cycle subsurface module;

FIG. 12 is a plan view of a Bai Bingjiao plane through a variable period subsurface module according to the present invention.

Detailed Description

The present invention will be described in detail below with reference to specific embodiments shown in the drawings. These embodiments are not intended to limit the invention and structural, methodological, or functional modifications of these embodiments that may be made by one of ordinary skill in the art are included within the scope of the invention.

It will be understood that terms, such as "having," "including," and "comprising," as used herein, do not preclude the presence or addition of one or more other elements or groups thereof.

Moreover, it should be understood that, although the terms first, second, etc. may be used herein to describe various elements or structures, these described elements should not be limited by the above terms. The above terms are used only to distinguish these descriptive objects from each other. For example, a first region may be referred to as a second region, and likewise, a second region may be referred to as a first region, without departing from the scope of this application.

In the various illustrations of the invention, certain dimensions of structures or portions may be exaggerated relative to other structures or portions for convenience of illustration, and thus serve only to illustrate the basic structure of the inventive subject matter.

Referring to fig. 1 to 9, a super surface 10 according to a preferred embodiment of the present invention is an artificial layered material having a thickness smaller than a wavelength, and may be regarded as a two-dimensional correspondence of the super material. The super surface 10 can realize the regulation and control of the polarization, phase, amplitude, frequency, propagation mode and other characteristics of electromagnetic waves through the super structure unit 12 with sub-wavelength on the surface, and realize the characteristics of beam shaping, beam deflection, superlens, superhologram, optical rotation, anti-reflection and the like.

Specifically, the super surface 10 in fig. 1 is applied to a collimating lens, the super surface 10 in fig. 2 is applied to a focusing lens, and the super surface in fig. 3 is applied to a deflection focusing lens.

Specifically, a supersurface 10 comprises a plurality of superstructures 12 arranged in an array. In the present embodiment, the super-structural unit 12 is a structural unit obtained by dividing the super-surface 10.

Further, the supersurface 10 has a first region 101 and a second region 102 in which the superstructures 12 are arranged. In this embodiment, the super-surface 10 includes at least two regions, and after dividing the super-surface 10 into different regions, the super-structure units 12 can be arranged in each region. The number of the super-structure units 12 is obtained according to the arrangement function, and the structural parameters of the super-structure units 12 can be obtained according to the corresponding phase distribution formula. The super-structure units 12 in the same region may have the same period or may have different periods.

For convenience of description, the following embodiments will take fig. 1 as an example, that is, the super surface 10 is applied to a scene of a collimating lens, and the super surface 10 is equally applicable to other scenes according to reversibility of an optical path. When the same laser is used to irradiate the surface 10, the incident angles of the light irradiated on the surface 10 are different, and the surface 10 is divided into regions according to the different incident angles in the same incident plane. In addition, each region is not overlapped with each other, and can be adjacent or spaced.

Further, the center of the first area 101 and the center of the second area 102 coincide with each other. In this embodiment, the super-structure units 12 on the super-surface 10 are preferably distributed in a ring shape, and the ring shape may be a closed structure as shown in fig. 1 and 2, or a non-closed structure as shown in fig. 3. Thus, the center of each region is then at the center of the ring, i.e., at point C in FIGS. 1-3. The center C point and the focal point of the super surface 10 are aligned along the Z axis, for example, the laser in fig. 1 is perpendicularly incident on the center C point, the laser is disposed on the same optical axis as the super surface 10, and the laser is located on the focal plane of the super surface 10. For example, light transmitted through the center point C in fig. 2 and 3 is incident on the CMOS/CCD.

As further shown with reference to fig. 4 and 5, the radial period 121 of the super-structure units 12 in the second region 102 corresponds to less than the radial period 121 of the super-structure units in the first region 101, and/or the circumferential period 122 of the super-structure units 12 in the second region 102 corresponds to less than the circumferential period 122 of the super-structure units in the first region 101.

In the present embodiment, the radial period 121 and the circumferential period 122 of the super-structure unit 12 in the second region 102 are each smaller than the radial period 121 and the circumferential period 122 of the super-structure unit 12 in the first region 101. Or the radial period 121 of the super-structure units 12 in the second region 102 corresponds to less than the radial period 121 of the super-structure units 12 in the first region 101, and the circumferential period 122 of the super-structure units 12 in the second region 102 is equal to the circumferential period 122 of the super-structure units 12 in the first region 101. Or the circumferential period 122 of the super-structure units 12 in the second region 102 corresponds to less than the circumferential period 122 of the super-structure units 12 in the first region 101, and the radial period 121 of the super-structure units 12 in the second region 102 is equal to the radial period 121 of the super-structure units 12 in the first region 101.

Specifically, different super-structure unit 12 periods are adopted in the first region 101 and the second region 102, and the different super-structure unit 12 periods may be different in radial period 121 and/or circumferential period 122, that is, the different super-structure unit 12 periods may be different in radial period 121, circumferential period 122, radial period 121 and circumferential period 122. The radial period 121 is a period value along the radial direction (direction indicated by L1 in fig. 4 and 5) of an imaginary circle formed on the plane of the X axis and the Y axis with the center C as the center. Similarly, the circumferential period 122 refers to a period value along the circumferential direction (the direction indicated by L2 in fig. 4 and 5) of an imaginary circle formed in the plane in which the X-axis and the Y-axis lie, or a period value along the central angle direction of the imaginary circle, around the center C.

With reference to fig. 7, it is preferable that the first region 101 is closer to the center C than the second region 102. Taking fig. 1, in which the super surface 10 is used as a collimating lens, the incident angles of light at the first region 101 and the second region 102 of the laser are different, i.e. the incident angle at the second region 1021 is larger than the incident angle at the first region 101. At this time, compared to the first region 101, the light irradiated in the second region 102 is incident at a large angle, and the period of the super-structure unit 12 in the second region 102 is set smaller than that of the super-structure unit 12 in the first region 101, so that the super-structure unit 12 in the second region 102 has a better modulation effect on the incident light at a large angle, and is suitable for a large Numerical Aperture (NA) system and a wide-angle imaging scene, and the efficiency or the wide-angle imaging quality of the large NA system can be improved.

Preferably, the first region 101 is located at a center point C and the second region 102 is located at an edge of the hypersurface 10 remote from the center point C. In this case, the super surface 10 is used as a collimator lens, for example, the incident light of the laser irradiated on the first region 101 is normal incidence or low angle incidence (for example, the incident angle is 0 ° to 5 °), and the incident light of the laser irradiated on the second region 102 is high angle incidence (for example, the incident angle is 45 ° to 50 °).

Specifically, the center and/or vertex position of each super-structure unit 12 is provided with a nanostructure 123. In this embodiment, the super-structure unit 12 is a structure unit centered on each of the nanostructures 123 by dividing the super-surface 10. The supersurface 10 further comprises a substrate 11 to which the nanostructures 123 are attached, and a plurality of nanostructures 123 are arranged on the substrate 11, wherein the nanostructures 123 in each cycle constitute one superstructural unit 12. The super-structure units 12 are in a close-packed pattern, which may be, for example, regular tetragons, regular hexagons, sectors, etc., each period containing one nanostructure 123, and the vertices and/or centers of the super-structure units 12 may be provided with nanostructures 123. In the case where the super-structure unit 12 is a regular hexagon, at least one nanostructure 123 is provided at each vertex and center position of the regular hexagon. The same is true for the case of a sector, square.

Further, the nanostructures 123 are configured as polarization dependent structures or polarization independent structures. In this embodiment, the nanostructure 123 can select a polarization dependent structure or a polarization independent structure according to the usage scene. Polarization independent structures such as cylinders, square cylinders, cross cylinders, circular-hole square cylinders, etc. Polarization dependent structures such as elliptic cylinders, rectangular cylinders, hexagonal prisms, etc.

Wherein the substrate 11 may be composed of a light transmissive or opaque material, the substrate 11 when transmitting light forms a transmissive supersurface, i.e., a transmissive superlens, such as the lenses of fig. 1-3. The substrate 11 is a reflective supersurface, i.e., a reflective superlens, when it is opaque or reflective. Materials for substrate 11 include, but are not limited to, quartz glass, crystalline and amorphous silicon, aluminum oxide, silicon nitride, calcium fluoride, and materials for nanostructure 123 include, but are not limited to, titanium oxide, tantalum oxide, hafnium oxide, silicon nitride, photoresist, quartz glass, aluminum oxide, crystalline and amorphous silicon, gallium nitride, crystalline germanium, selenium sulfide, chalcogenide glass.

Preferably, after the plurality of nanostructures 123 are arranged on the substrate 11, the nanostructures are circular in plan view, that is, circular in a plane where the X-axis and the Y-axis are located, and at this time, the first area 101 and the second area 102 are both in a closed circular shape, the center of the first area 101 and the center of the second area 102 are both coincident with the center C, the first area 101 is located at the center of the circle, and the second area 102 is located at the outer circle.

Of course, as shown in fig. 3, the first region 101 may not be located at the center of the circle, and the second region 102 may not be located at the outer circle.

Moreover, the plurality of nanostructures 123 on the substrate 11 in this manner are centrally symmetric in the plane of the X-axis and Y-axis, thereby enabling the super surface 10 to modulate the light beam in multiple directions, thereby adapting to more scenes.

Referring to fig. 4, the present invention provides a top view and a partially enlarged schematic view of the upper surface 10 in a preferred embodiment. This embodiment only varies the radial period 121 relative to a constant period supersurface.

Specifically, the radial period 121 of each super-structure unit 12 decreases in the direction from the first region 101 to the second region 102, and the circumferential period 122 of each super-structure unit 12 is equal. In this embodiment, the direction from the first region 101 to the second region 102 means: in the direction from the center (i.e., center C) to the outer circle. The radial period 121 of all the super-structure units 12 on the super-surface 10 is in a decreasing trend in the direction from the center (i.e., center C) to the outer circle, and the circumferential period 122 of all the super-structure units 12 remains unchanged. It can be seen that the entire subsurface 10 adopts a variable period scheme. Therefore, compared to the constant period of the super surface, the nano structures 123 of the super surface 10 in the present embodiment are denser along the radial direction (i.e. the L1 direction in the figure) of the first region 101, so that the structure is relatively simple and the manufacturing difficulty is low while the effect of better modulating the incident light with a large angle is satisfied.

In addition, in the present embodiment, a rectangle is formed between the centers of the adjacent four nanostructures 123 at the edge of the super surface 10, and the aspect ratio of the rectangle is larger as the distance from the center C increases.

In an embodiment not shown, the circumferential period 122 of all the super-structural units 12 on the super-surface 10 is in a decreasing trend in the direction from the center (i.e. the center C) to the outer circle, and the radial period 121 of all the super-structural units 12 is kept unchanged, so that a better modulation effect on the incident light with a large angle can be satisfied.

Referring to fig. 5, the present invention provides a top view and a partially enlarged schematic view of the upper surface 10 in another preferred embodiment. Compared to the above-described embodiments, the present embodiment changes both the radial period 121 and the circumferential period 122.

Specifically, the radial period 121 and the circumferential period 122 of each super-structure unit 12 decrease in the direction from the first region 101 to the second region 102. In this embodiment, the direction from the first region 101 to the second region 102 means: in the direction from the center (i.e., center C) to the outer circle. The radial period 121 and the circumferential period 122 of all the super-structure units 12 on the super-surface 10 are in a decreasing trend in the direction from the center (i.e., center C) to the outer circle. It can be seen that the entire subsurface 10 adopts a variable period scheme. Therefore, compared to the above-described embodiments, the nanostructures 123 of the super-surface 10 in this embodiment are denser along the radial direction and the circumferential direction of the first region 101, and have a better modulation effect on the incident light of a large angle.

In addition, in the present embodiment, at the edge of the super surface 10, a square is formed between the centers of the adjacent four nanostructures 123.

In both of the above embodiments, the varying period is employed throughout all regions of the subsurface 10. With the improvements of the two embodiments, the efficiency of the super surface 10 at different incident angles is finally obtained as shown in fig. 6. In the figure, the abscissa corresponds to the incident angle, the ordinate corresponds to the super-surface efficiency, the broken line drawn broken line (ModeA in the figure) is the super-surface of the variable period scheme in the embodiment of FIG. 5, the broken line drawn broken line (ModeB in the figure) is the super-surface of the variable period scheme in the embodiment of FIG. 4, and the broken line drawn in the solid line is the super-surface of the fixed period scheme (425 nm period), as can be seen from the figure, the efficiency is greater than that of the super-surface of the fixed period in any incident angle in the two embodiments of the super-surface with the variable period provided by the invention, and the embodiment corresponding to FIG. 5 has higher efficiency.

Further, as shown in fig. 7, the super surface 10 further has a third region 103 in which the super structural units 12 are arranged, and the centers of the circles of the first region 101, the third region 103 and the second region 102 are coincident with each other, and the outer diameter sizes sequentially increase. In this embodiment, the third region 103 is interposed between the first region 101 and the second region 102, and the centers of the three regions are coincident with the center C and not coincident with each other. As shown in fig. 1, the third region 103 is preferably disposed adjacent to the first region 101 and the second region 102, and thus, the first region 101, the third region 103, and the second region 102 are sequentially arranged from the center (i.e., center C) to the outer circumference of the super surface 10.

Of course, as shown in fig. 2, the third region 103 may be spaced apart from the first region 101 and the second region 102.

Alternatively, as shown in fig. 3, the first region 101, the third region 103 and the second region 102 may have a ring shape that is not closed.

Specifically, the radial period 121 and/or the circumferential period 122 of the super-structure unit 12 in the third region 103 decreases from the first region 101 to the second region 102.

In this embodiment, when the third region 103 is disposed adjacent to the first region 101 and the second region 102, the period (including the radial period 121 and/or the circumferential period 122) of the super-structure units 12 in the third region 103 decreases from the center (i.e. the center C) to the outer circle, so that all the super-structure units 12 in the region between the first region 101 and the second region 102 adopt a variable period scheme, and the regions outside the first region 101 and the second region 102 can adopt a constant period or variable period scheme, so that the modulation effect on the incident light at different angles between the first region 101 and the second region 102 is better.

And when the third region 103 is spaced apart from the first and second regions 101 and 102, for example, one or more regions are spaced apart between the first and second regions 101 and 102. The radial period 121 and/or the circumferential period 122 of the super-structure unit cells 12 in the third region 103 are in a decreasing trend in the direction from the center (i.e., center C) to the outer circle. That is, in the direction from the center (i.e., center C) to the outer circle, the radial period 121 and/or the circumferential period 122 of the super-structure unit 12 in at least one of the plurality of regions between the first region 101 and the second region 102 is in a decreasing trend, while the periods of the super-structure unit 12 in the other regions of the plurality of regions are kept constant.

The two modes enable at least part of the region of the super surface 10 to adopt a variable period scheme, and the rest region can adopt a constant period.

Of course, in an embodiment not shown, the period of the super-structure unit 12 (including the radial period 121 and/or the circumferential period 122) within the third region 103 may also take a constant period.

Further, the radial period 121 and the circumferential period 122 of the super-structure unit 12 in the first region 101 and/or the second region 102 remain unchanged. In this embodiment, the super-structure units 12 in the first region 101 have a constant period, and the super-structure units 12 in the second region 102 have a variable period. Or the super-structure units 12 in the first region 101 may have a variable period and the super-structure units 12 in the second region 102 may have a constant period. Or the super-structure units in the first region 101 and the second region 102 each adopt a constant period.

Taking the example that the super-surface 10 is applied to a collimating lens, since the incident light irradiated by the laser on the first region 101 is normal incidence or low-angle incidence, the influence of the variable period on the modulating effect by the super-structure units 12 in the region is small. Also, the incident light of the light irradiated by the laser at the second region 102 is incident at a large angle, the super-structure unit 12 within this region has little influence on the modulation effect with the period of variation, and no more nano-structures 123 can be accommodated at the edge of the second region 102. Thus, employing a constant period within the first region 101 and/or the second region 102 (including the radial period 121 and the circumferential period 122) can reduce the difficulty of manufacturing the subsurface 10 and have less impact on the subsurface efficiency.

Further, the radial period 121 and/or the circumferential period 122 of the super-structure unit 12 in the third region 103 is equal in proportion to the first region 101 to the second region 102. In this embodiment, the period (including the radial period 121 and/or the circumferential period 122) of the super-structure units 12 in the third region 103 is smaller than the super-structure units 12 in the first region 101, and is larger than the super-structure units 12 in the second region 102. The period of the super-structure unit 12 in the third region 103 is changed in equal proportion, so that the period values corresponding to all incident angles in the third region 103 do not need to be acquired, and the manufacture of the super-surface 10 is facilitated.

Specifically, by acquiring the incidence angles and the period values corresponding to the first region 101 and the second region 102 or their average values (for example, when there are a plurality of incidence angles in the first region 101 or the second region 102), a first linear function is established between the incidence angles and the period values, and the period of the super-structure unit 12 and the corresponding incidence angle in the third region 103 can be obtained by substituting the first linear function, thereby simplifying the design and manufacturing process of the super-surface 10.

Of course, in some embodiments, other functions, such as quadratic functions, may also be established according to the incident angles and the period values corresponding to the first region 101 and the second region 102.

Further, the third region 103 has a first region 1031, a second region 1032, and a third region 1033 with sequentially increasing outer diameter sizes. In this embodiment, as shown in fig. 1, the third region 103 is further divided to obtain a first region 1031, a second region 1032, and a third region 1033 with mutually coincident circle centers. Taking the case of the super surface 10 being used as a collimator lens, the incident angles of the incident light to the three regions are different. For example, the angle of incidence of the light on the first region 1031 is between 5 ° and 15 °, the angle of incidence of the light on the second region 1032 is between 15 ° and 30 °, and the angle of incidence of the light on the third region 1033 is between 30 ° and 45 °.

Specifically, the radial period 121 and/or the circumferential period 122 of the super-structure unit cells 12 in the first region 1031 decrease from the first region 101 to the second region 1032 in equal proportion. In this embodiment, by obtaining the incidence angles and the period values corresponding to the first region 101 and the second region 1032 or the average value thereof (for example, when there are a plurality of incidence angles in the first region 101 or the second region 1032), a second linear function is established between the incidence angles and the period values, and the period of the super-structure unit 12 in the first region 1031 and the corresponding incidence angle can be obtained by substituting the second linear function, so that the period values corresponding to all incidence angles in the first region 1031 do not need to be obtained, and the manufacture of the super-surface 10 is facilitated.

Specifically, the radial period 121 and/or the circumferential period 122 of the super-structure unit(s) 12 in the second region 1032 decreases from the first region 1031 to the third region 1033 in equal proportion. In this embodiment, by obtaining the incidence angles and the period values corresponding to the first region 1031 and the third region 1033 or the average values thereof (for example, when there are a plurality of incidence angles in the first region 1031 or the third region 1033), a third linear function is established between the incidence angles and the period values, and the period of the super-structure unit 12 in the second region 1032 and the corresponding incidence angle can be obtained by substituting the third linear function, so that it is not necessary to obtain the period values corresponding to all incidence angles in the second region 1032, and the manufacture of the super-surface 10 is facilitated.

Specifically, the radial period 121 and/or the circumferential period 122 of the super-structure unit(s) 12 in the third region 1033 are (are) equally proportioned decreasing from the second region 1032 to the second region 102. In this embodiment, by obtaining the incidence angles and the period values corresponding to the second region 1032 and the second region 102 or the average value thereof (for example, when there are a plurality of incidence angles in the second region 1032 or the second region 102), a fourth linear function is established between the incidence angles and the period values, and the period of the super-structure unit 12 in the third region 1033 and the corresponding incidence angle can be obtained by substituting the fourth linear function, so that the period values corresponding to all incidence angles in the third region 1033 do not need to be obtained, and the manufacture of the super-surface 10 is facilitated.

Therefore, the third region 103 is further divided into regions, and the linear functions corresponding to the respective regions are calculated, so that the super-structure units 12 are more accurately arranged, the modulation effect generated by the period of the super-structure units 12 in the third region 103 is better, and the overall efficiency of the super-surface 10 is higher.

Of course, in other embodiments, the third region 103 may also be divided into other numbers of regions, such as two regions, four regions, five regions, and so on.

As further shown with reference to fig. 8 and 9, the super surface 10 further includes a substrate 11 connecting the nanostructures 123, a filler 14 connecting the nanostructures 123 and the substrate 11, and an anti-reflection film 13 disposed on the substrate 11 and/or the filler 14. In this embodiment, the antireflection film 13 is preferably provided on both the substrate 11 and the filler 14. At this time, one layer of the anti-reflection film 13 covers the surface of the filler 14 on the side facing away from the substrate 11, and the other layer of the anti-reflection film 13 covers the surface of the substrate 11 on the side facing away from the nanostructure 123. That is, as shown in fig. 7, the light incident side and the light emitting side of the upper surface 10 are covered with an antireflection film 13. By providing the antireflection film 13, the reflectance can be reduced, thereby improving the transmittance of the super surface and further improving the super surface efficiency.

Specifically, the antireflection film 13 includes a first material layer 131 and a second material layer 132. In this embodiment, the first material layer 131 is preferably silicon nitride, and the second material layer 132 is preferably silicon oxide, so as to satisfy the high-transmittance condition when the light beam is incident at a large angle.

Specifically, the first material layer 131 or the second material layer 132 is connected to the super surface 10. In this embodiment, different material layers are selected to be connected to the substrate 11 and the filler 14 according to their materials. For example, as shown in fig. 8 and 9, when silicon oxide is used for both the substrate 11 and the filler 14, the first material layer 131 (i.e., silicon nitride) is connected to the substrate 11 and the filler 14, and the second material layer 132 is connected to the outer side of the first material layer 131. Also, when other materials are used for the substrate 11 and the filler 14, the second material layer 132 may be connected to the substrate 11 and the filler 14.

Preferably, as shown in fig. 8, the antireflection film 13 on both sides of the upper surface 10 employs a first material layer 131 and a second material layer 132. When the wavelength of the incident light is 940nm, the thickness of the first material layer 131 is preferably 50nm + -5 nm, and the thickness of the second material layer 132 is preferably 215nm + -5 nm, so that the optimal super-surface efficiency is obtained.

Preferably, as shown in fig. 9, two first material layers 131 and two second material layers 132 are used for the antireflection film 13 on both sides of the upper surface 10. When the wavelength of the incident light is 940nm, the thickness of the first material layer 131 is preferably 40nm±5nm, the thickness of the second material layer 132 is preferably 55nm±5nm, the thickness of the first material layer 131 is preferably 380nm±5nm, and the thickness of the second material layer 132 is preferably 165nm±5nm on the light-emitting side of the super surface 10 in the direction from the light-incident side to the light-emitting side, so that the optimal super surface efficiency is obtained.

In the above embodiment, the efficiency of the super surface 10 at different incident angles is shown in fig. 10. In the figure, the abscissa corresponds to the incident angle, the ordinate corresponds to the efficiency of the hypersurface, the broken line drawn by the broken line is the hypersurface of the preferable variable period scheme, the broken line drawn by the solid line is the hypersurface of the fixed period (the period is 425 nm) scheme, and as can be seen from the figure, the efficiency of the hypersurface with the variable period provided by the invention is larger than that of the hypersurface with the fixed period at any incident angle.

It can be seen from fig. 11 and fig. 12 that after the super-surface focusing with the variable period of the present invention, the uniformity and efficiency of different fields of view are greatly improved, the light intensity and darkness abrupt change is reduced, and the practicability is greatly increased.

According to another aspect of the invention, there is also provided a near infrared imaging system provided with a super surface 10 according to the invention, the super surface 10 preferably being a focusing lens.

Specifically, the near infrared imaging system further comprises a lens barrel, an optical detector module, an optical narrow-band filter and the like. When in use, the light reflected or scattered by the object to be imaged is focused by the super surface 10, the light of other wave bands is filtered by the optical narrow-band filter and then is collected by the optical detector module and imaged on the photosurface of the optical detector module, and the photosurface absorbs the near infrared light of the object to be imaged and converts the near infrared light into an image electric signal to be output.

It should be understood that although the present disclosure describes embodiments, not every embodiment is provided with a separate embodiment, and that this description is for clarity only, and that the skilled artisan should recognize that the embodiments may be combined as appropriate to form other embodiments that will be understood by those skilled in the art.

The above list of detailed descriptions is only specific to practical embodiments of the present invention, and they are not intended to limit the scope of the present invention, and all equivalent embodiments or modifications that do not depart from the spirit of the present invention should be included in the scope of the present invention.

Claims (10)

1. The super-surface comprises a plurality of super-structure units which are arrayed, and is characterized in that the super-surface is provided with a first area and a second area, wherein the first area and the second area are arrayed, the centers of the first area and the second area are mutually overlapped, the first area is closer to the center than the second area, the radial period of the super-structure units in the second area is smaller than the radial period of the super-structure units in the first area, and/or the circumferential period of the super-structure units in the second area is smaller than the circumferential period of the super-structure units in the first area.

2. The metasurface of claim 1, wherein the radial period of each super-structure unit decreases in a direction from the first region to the second region, and the circumferential period of each super-structure unit is equal.

3. The metasurface of claim 1, wherein the radial period and circumferential period of each super-structure unit decreases in a direction from the first region to the second region.

4. The supersurface according to claim 1, wherein said supersurface further has a third region in which the superstructures are arranged, the centers of the circles of said first region, third region and second region being coincident with each other and the outside diameter dimension being sequentially increased, the radial period and/or circumferential period of the superstructures in said third region decreasing in the direction from the first region to the second region.

5. The metasurface of claim 4, wherein the radial period and circumferential period of the super-structure units in the first region and/or the second region remain unchanged.

6. The metasurface of claim 4, wherein the radial period and/or circumferential period of the super-structure units in the third region decreases in equal proportion from the first region to the second region.

7. The metasurface of claim 4, wherein the third region has a first region, a second region, and a third region with sequentially increasing outside diameter dimensions, wherein the radial period and/or circumferential period of the super-structure units within the first region decreases in equal proportion from the first region to the second region, wherein the radial period and/or circumferential period of the super-structure units within the second region decreases in equal proportion from the first region to the third region, and wherein the radial period and/or circumferential period of the super-structure units within the third region decreases in equal proportion from the second region to the second region.

8. The metasurface of claim 1, wherein the center and/or vertex position of each super-structure unit is provided with a nanostructure configured as a polarization dependent structure or as a polarization independent structure.

9. The metasurface of claim 8, further comprising a substrate connecting the nanostructures, a filler connecting the nanostructures and the substrate, and an anti-reflection film disposed on the substrate and/or the filler, the anti-reflection film comprising a first material layer and a second material layer, the first material layer or the second material layer being connected to the metasurface.

10. A near infrared imaging system comprising a subsurface as claimed in any one of claims 1-9.