Fully-integrated polarization imaging device based on polarization beam splitting super lens

Abstract

The utility model relates to the technical field of super-structure lenses, and particularly discloses a fully-integrated polarization imaging device based on a polarization beam splitting super-lens. The fully-integrated polarization imaging device based on the polarization beam splitting superlens comprises a nanopillar array, a transparent medium substrate and an image sensor, a nanorod array is arranged on one side surface of the transparent medium substrate; the image sensor is arranged on the other side, far away from the nanorod array, of the transparent medium substrate; the image sensor is provided with at least two pixel areas; the light beams output from the nano-pillar array pass through the transparent medium substrate and then are split and focused to the pixel area. According to the utility model, the nanorod array, the transparent medium substrate and the image sensor are integrated together, so that the interference of an external light path is reduced, the imaging stability and reliability are improved, the structure is compact, and the size is small. The nanorod array can accurately control polarization and phase of light, high-resolution imaging is achieved, and the problems that an existing polarization system is low in integration degree, large in size and low in resolution are solved.

Description

TECHNICAL FIELD

[0001] The utility model relates to super lens technical field especially relates to a kind of full integration polarization imaging devices based on polarization beam splitting super lens. BACKGROUND

[0002] Polarization imaging system generally needs to carry out polarization filtering or beam splitting to original image, and currently there are three kinds of polarization imaging systems: division of time polarimeter (DoTP), division of amplitude polarimeter (DoAmP) and division of aperture polarimeter (DoAP).But the common shortcomings of the above systems are that polarization imaging system is too large, imaging precision is low, and it is difficult to be applied to integrated and miniaturized application scenarios.

[0003] At present, polarization imaging technology based on super surface has been greatly developed, and polarization imaging device of full Stokes vector is realized, and its basic principle is to use polarization-dependent super surface to make six different polarization state beam splitting regions, and then realize polarization state beam splitting measurement.However, this technology also has the shortcomings of low spatial resolution, large energy loss and difficulty in integration with image sensor (pixel size does not correspond).

[0004] Therefore, how to improve the low integration level, large size, low resolution and high loss problems existing in the existing polarization imaging system is an urgent problem to be solved in the industry. UTILITY MODEL CONTENT

[0005] The utility model provides a kind of full integration polarization imaging devices based on polarization beam splitting super lens to solve the low integration level, large size and low resolution problems existing in the existing polarization imaging system.

[0006] The utility model provides a kind of full integration polarization imaging devices based on polarization beam splitting super lens, comprising:

[0007] Nanopillar array;

[0008] Transparent medium substrate, one side of the transparent medium substrate is provided with the nanopillar array;

[0009] Image sensor, is set to the other side of the transparent medium substrate away from the nanopillar array;The image sensor has at least two pixel regions on it;The light beam output from the nanopillar array is split and focused to the pixel region after passing through the transparent medium substrate.

[0010] The utility model provides a full integration polarization imaging device based on polarization beam splitting superlens, the nanometer post array includes:

[0011] Multiple nanometer post units, multiple nanometer post units are arranged on one side of the transparent medium substrate, and the nanometer post unit is a polarization dependent super atom or a polarization independent super atom.

[0012] The utility model provides a full integration polarization imaging device based on polarization beam splitting superlens, and the polarization dependent super atom is rectangular column structure.

[0013] The utility model provides a full integration polarization imaging device based on polarization beam splitting superlens, and the polarization dependent super atom is rectangular column structure.

[0014] The utility model provides a full integration polarization imaging device based on polarization beam splitting superlens, and when the nanometer post unit is the polarization independent super atom, the full integration polarization imaging device based on polarization beam splitting superlens further includes:

[0015] Multi -directional polaroid is set up in the nanometer post array away from the other side of the transparent medium substrate, is used for carrying out multi -directional polarization to the incident light beam, to give nanometer post array input multi -directional polarized light.

[0016] The utility model provides a full integration polarization imaging device based on polarization beam splitting superlens, and the polarization independent super atom is cylindrical structure.

[0017] The utility model provides a full integration polarization imaging device based on polarization beam splitting superlens, and the polarization independent super atom is cylindrical structure.

[0018] The utility model provides a full integration polarization imaging device based on polarization beam splitting superlens, and the multi -directional polaroid includes:

[0019] The substrate has multiple nanometer grating subareas, and the polaroid is arranged in the nanometer grating subarea, and the polarization directions of the polaroids of the multiple nanometer grating subareas are different.

[0020] The utility model provides a full integration polarization imaging device based on polarization beam splitting superlens, and the grating period of the nanometer grating subarea is 110nm to 160nm, and the grating duty cycle is 0.3 to 0.7.

[0021] The image sensor comprises:

[0022] The filter layer is connected with the transparent medium substrate on the side of the transparent medium substrate.

[0023] The full-integrated polarization imaging device based on the polarization beam splitting superlens has the advantages that the nanometer column array, the transparent medium substrate and the image sensor are integrated together, external light path interference can be reduced, imaging stability and reliability can be improved, the structure is compact, the volume is small, and the full-integrated polarization imaging device based on the polarization beam splitting superlens is convenient to use in portable devices. The transparent medium substrate plays the roles of supporting the nanometer column array and connecting the nanometer column array and the image sensor, and the light beams are focused and split at the transparent medium substrate after passing through the nanometer column array. The nanometer column array can accurately control the polarization and phase of the light, and high-resolution imaging is realized. The light beams are split and focused to the pixel areas after passing through the transparent medium substrate, and the imaging definition is improved. The nanometer column array and the transparent medium substrate jointly act, the collection and utilization efficiency of the light are improved, and the imaging brightness and contrast are enhanced. The multiple pixel areas on the image sensor can simultaneously capture the light in different polarization states, multi-channel imaging is realized, and the full-integrated polarization imaging device based on the polarization beam splitting superlens is suitable for various application scenarios. The nanometer column array and the image sensor are arranged on the two sides of the transparent medium substrate, the manufacturing process is simplified, and the cost is reduced. The full-integrated polarization imaging device based on the polarization beam splitting superlens solves the problems of low integration degree, large size and low resolution of the existing polarization imaging system. BRIEF DESCRIPTION OF DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0025] Figure 1 is one of the three-dimensional structure schematic views of the full-integrated polarization imaging device based on the polarization beam splitting superlens provided by the present application.

[0026] Figure 2 is Figure 1 is the structure schematic view of the full-integrated polarization imaging device based on the polarization beam splitting superlens under the main visual vision.

[0027] Figure 3 is the second three-dimensional structure schematic view of the full-integrated polarization imaging device based on the polarization beam splitting superlens provided by the present application.

[0028] Figure 4 is Figure 3Structure schematic diagram of the full integration polarized imaging device based on the polarization beam splitting superlens under the main visual vision.

[0029] Figure 5 Is the structure schematic diagram of the nanometer column unit of the rectangular column structure provided by the utility model.

[0030] Figure 6 Is the structure schematic diagram of the nanometer column unit of the cylindrical structure provided by the utility model.

[0031] Figure 7 Is the simulation result of the polarization related super atom (height 1.2 microns) of the rectangular column structure. ; b is the phase change distribution when the vertical polarization is incident, and the change range covers ; c is the transmittance distribution, and the average transmittance is more than 80%; d is the horizontal / vertical polarization phase distribution, and the dark point is the polarization beam splitting superlens design requirement point, and the light point is the point contained in the polarization related super atom database.

[0032] Figure 8 Is the polarization beam splitting superlens design process: (1) get the phase distribution design value; (2) find the corresponding value with the minimum error in the polarization related super atom database; (3) design the length and width of the nanometer column unit of the rectangular structure according to the database, and get the actual horizontal / vertical polarization phase response value through simulation.

[0033] Figure 9 Is the simulation result of the polarization beam splitting superlens: a is that the non-polarized light is incident, and is split and focused to two areas by the superlens; b is that the horizontal polarized light is incident, and is only focused to the left focal point (2.5 microns) position; c is the corresponding focal length (6 microns) of the horizontal polarized light; d is that the vertical polarized light is incident, and is only focused to the right focal point position; e is the corresponding focal length (6 microns) of the vertical polarized light.

[0034] Reference signs:

[0035] 2, nanometer column array; 3, transparent medium substrate; 4, light filter layer; 5, photosensitive layer; 6, circuit layer; 7, base layer; 8, protective layer; 9, image sensor; 21, nanometer column unit; 13, multi-directional polaroid. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical scheme and advantages of the utility model more clear, the technical scheme in the utility model will be described clearly and completely in combination with the drawings in the utility model below. Obviously, the described embodiments are part of the embodiments of the utility model, rather than all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by the ordinary skilled in the art without creative labor belong to the protection scope of the utility model.

[0037] Polarization imaging systems generally need to perform polarization filtering or beam splitting on original images, and currently there are three kinds of polarization imaging systems: division of time polarimeter (DoTP), division of amplitude polarimeter (DoAmP) and division of aperture polarimeter (DoAP).

[0038] The division of time polarimeter (DoTP) acquires intensity images of different polarization directions at different times by introducing dynamic elements (such as a rotating polarizer or a spatial light modulator to apply different phase delays to a fixed polarizer) and then inversely solving the polarization information. The overall imaging accuracy of this system is low, the system is redundant and difficult to apply to polarization imaging at micro-nano scale.

[0039] The division of amplitude polarimeter (DoAmP) uses a beam splitter prism to simultaneously split the incident light into multiple beams, which are then modulated by a beam splitting device and incident into corresponding detectors to obtain intensity images with different polarization information. This system can obtain multiple polarization component images at the same time, but because there are multiple optical subsystems and CCD detection systems, the volume is large, the cost is high, and the parameter differences of each subsystem are easy to cause errors.

[0040] The division of aperture polarimeter (DoAP) uses off-axis eccentricity to simultaneously split the incident light into four beams, and different polarization devices are placed in each light path to simultaneously obtain multiple polarization information of different directions of the same target on the focal plane of the detector. This system has the problem of loss of spatial resolution, and the final synthesized polarization image is only one quarter of the detection area of the detector, and it is difficult to adjust the best imaging focal plane of each channel to ensure the accuracy of the polarization information.

[0041] Before introducing the specific structure of the utility model, the related theoretical knowledge will be briefly introduced.

[0042] Polarization refers to the direction of light wave vibration, i.e., the phenomenon of loss of symmetry of spatial distribution of electric vector vibration of light wave relative to the direction of light beam propagation, which is one of the intrinsic properties of light. The polarization information of light refers to the physical quantity carried by the polarization state of light wave, mainly including the following aspects:

[0043] Degree of Polarization (DOP): refers to the proportion of a certain polarization state of light in the total light intensity. Generally, it refers to the polarization state with the maximum intensity.

[0044] Polarization State: describes the state of vibration direction and intensity distribution of light wave, including linear polarization, elliptical polarization and circular polarization, etc.

[0045] Polarization Axis: for linearly polarized light or elliptically polarized light, the direction of vibration or the short axis and long axis of the ellipse is the polarization axis.

[0046] Polarization Angle: for linearly polarized light or elliptically polarized light, the angle between the direction of vibration or the short axis and long axis of the ellipse and a certain reference direction is the polarization angle.

[0047] Polarization Imaging is a technology that uses the polarization state of light to obtain image information, mainly by measuring the Stokes vector of the target to obtain the polarization information of the target. The Stokes vector contains four parameters representing the intensity of light in different polarization states:

[0048]

[0049] where represent the intensity of light corresponding to 0°, 90°, 45°, 135° and left-handed, right-handed polarization states, respectively. In the image, polarization information can affect the brightness, color and details of the image, and can be used to reveal hidden information in the image. Polarization imaging can enhance the contrast of objects that are difficult to distinguish, improve the sensitivity of imaging and obtain physical characteristics that cannot be detected by conventional imaging, such as surface texture and material properties, etc., and has important applications in machine vision, optical measurement and detection, etc.

[0050] Metasurface is a two-dimensional planar metamaterial with subwavelength thickness, which can flexibly control the amplitude, phase, dispersion, momentum and polarization of electromagnetic waves. Metalens, also known as superlens or super surface structure lens, is a kind of optical metasurface that can realize the imaging function of lens. By combining and arranging the subwavelength artificial structure, the phase and other parameters of the incident light can be locally regulated to form a phase distribution corresponding to the focusing wave surface, so as to realize the function of lens focusing or imaging. Metalens is a super-light and super-thin planar structure, which has important application potential in the miniaturization, intelligentization and integration of optoelectronic devices and optical systems.

[0051] Nanoimprint is a technology for manufacturing nanoscale structures by using a high-precision and high-resolution imprint mold to replicate patterns or structures onto a substrate. It is expected to realize large-scale preparation of metalens by using nanoimprint technology.

[0052] The structure and principle of the full-integrated polarization imaging device based on the polarization beam splitting metasurface lens will be described in detail below. Figures 1 to 9 The structure and principle of the full-integrated polarization imaging device based on the polarization beam splitting metasurface lens will be described in detail below.

[0053] As shown in Figures 1 to 4 The embodiment of the full-integrated polarization imaging device based on the polarization beam splitting metasurface lens provided by the present application comprises a nanocolumn array 2, a transparent dielectric substrate 3 and an image sensor 9. The nanocolumn array 2 is arranged on one side of the transparent dielectric substrate 3. The image sensor 9 is arranged on the other side of the transparent dielectric substrate 3 away from the nanocolumn array 2. The image sensor 9 has at least two pixel areas. The light beams output from the nanocolumn array 2 are split and focused to the pixel areas after passing through the transparent dielectric substrate 3.

[0054] In this embodiment, the nanopillar array 2, the transparent dielectric substrate 3, and the image sensor 9 are integrated together, which reduces external optical path interference, improves imaging stability and reliability, and features a compact structure and small size, making it easy to use in portable devices. The transparent dielectric substrate 3 supports the nanopillar array 2 and connects the nanopillar array 2 and the image sensor 9. After the light beam passes through the nanopillar array 2, it is focused and split at the transparent dielectric substrate 3. The nanopillar array 2 can precisely control the polarization and phase of the light to achieve high-resolution imaging. After the light beam passes through the transparent dielectric substrate 3, it is split and focused onto the pixel area, improving the image clarity. The nanopillar array 2 and the transparent dielectric substrate 3 work together to improve the light collection and utilization efficiency, enhancing the image brightness and contrast. Multiple pixel areas on the image sensor 9 can simultaneously capture light with different polarization states, achieving multi-channel imaging, suitable for various application scenarios. The nanopillar array 2 and the image sensor 9 are located on both sides of the transparent dielectric substrate 3, simplifying the manufacturing process and reducing costs. The fully integrated polarization imaging device based on a polarization beam-splitting superlens in this embodiment solves the problems of low integration, large size, and low resolution of existing polarization systems.

[0055] Specifically, the top side of the image sensor 9 is connected to the nanopillar array 2 via a transparent dielectric substrate 3. The transparent dielectric substrate 3 covers the top side of the image sensor 9.

[0056] like Figure 2 and Figure 4 As shown, the image sensor 9 further includes a filter layer 4; the side of the filter layer 4 facing the transparent dielectric substrate 3 is connected to the transparent dielectric substrate 3.

[0057] Specifically, taking a back-illuminated image sensor as an example, after etching away the traditional microlens array structure at the top, a nanopillar array 2 is installed on the side of the filter layer 4 of the image sensor 9 facing the transparent dielectric substrate 3.

[0058] Furthermore, the image sensor 9 also includes a photosensitive layer 5, a circuit layer 6, a substrate layer 7, and a protective layer 8; the photosensitive layer 5 is disposed on the side of the filter layer 4 away from the transparent dielectric substrate 3; the circuit layer 6 is disposed on the side of the photosensitive layer 5 away from the filter layer 4; the substrate layer 7 is disposed on the side of the circuit layer 6 away from the photosensitive layer 5; and the protective layer 8 is disposed on the side of the substrate layer 7 away from the circuit layer 6. The light beam, after passing through the nanopillar array 2, the transparent dielectric substrate 3, and the filter layer 4, is focused within the photosensitive region at the center of the top of the photosensitive layer 5.

[0059] It should be noted that the structure of the image sensor 9 is in the prior art, therefore, each layer of the image sensor 9 will not be described in detail in this embodiment.

[0060] In some embodiments, the transparent dielectric substrate 3 is made of silicon dioxide.

[0061] Further, the transparent medium substrate 3 is designed according to a beam splitting focal length. Preferably, the thickness of the transparent medium substrate 3 can be 1 micrometer.

[0062] In some embodiments, the nanocolumn array 2 comprises a plurality of nanocolumn units 21; the plurality of nanocolumn units 21 are arranged in an array on one side of the transparent medium substrate 3; the nanocolumn units 21 are polarization-dependent superatoms or polarization-independent superatoms.

[0063] It should be noted that the polarization-dependent superatom can exhibit a unique electromagnetic response under a specific polarized light. The polarization-independent superatom can maintain consistent electromagnetic response under different polarized light.

[0064] As shown in FIG. 2, the polarization-dependent superatom can be a rectangular column structure. The polarization-dependent superatom has a size of 800-1200 nanometers in the Z-axis direction, a size of 100-600 nanometers in the X-axis direction, and a size of 100-600 nanometers in the Y-axis direction. The size of the polarization-dependent superatom in the X-axis direction is different from the size of the polarization-dependent superatom in the Y-axis direction. Figure 5 In this embodiment, the size of the polarization-dependent superatom in the X-axis direction is different from the size of the polarization-dependent superatom in the Y-axis direction. Therefore, the phase control of the horizontal polarization and the vertical polarization is different, thereby introducing the polarization degree of freedom control. By precisely designing the size and arrangement of the nanocolumn units 21, high-precision control of light can be achieved, and the imaging resolution can be improved. The size of the nanocolumn units 21 in the Z-axis direction is 800-1200 nanometers, and the size in the X-axis and Y-axis directions is 100-600 nanometers. Efficient polarization beam splitting and focusing can be achieved in a wide spectral range. It can be ensured that the phase delay in the horizontal polarization and the vertical polarization can cover

[0065] a square region of this parameter space, while also ensuring the focusing efficiency of the nanocolumn units 21.

[0066] Further, the period of the nanocolumn array 2 formed by the polarization-dependent superatom array is not less than 600 nanometers. Preferably, the period of the nanocolumn array 2 formed by the polarization-dependent superatom array is 700 nanometers.

[0067] Preferably, the size of the polarization-dependent superatom in the Z-axis direction, i.e., the height of the polarization-dependent superatom of the rectangular column structure, can be 800 nanometers, 1200 nanometers, or any value between 800 nanometers and 1200 nanometers.

[0068] ​Optionally, the size of the polarization-dependent superatom in the X-axis direction, i.e., the length of the polarization-dependent superatom of the rectangular column structure, can be 100 nanometers, can be 600 nanometers, or can be any value between 100 nanometers and 600 nanometers.

[0069] Optionally, the size of the polarization-dependent superatom in the Y-axis direction, i.e., the length of the polarization-dependent superatom of the rectangular column structure, can be 100 nanometers, can be 600 nanometers, or can be any value between 100 nanometers and 600 nanometers.

[0070] It should be noted that in the X-axis direction and the Y-axis direction, the longer side of the polarization-dependent superatom is defined as the length of the polarization-dependent superatom, and the shorter side of the polarization-dependent superatom is defined as the width of the polarization-dependent superatom.

[0071] Optionally, each rectangular column structure of the nanorod unit 21 corresponds to two adjacent pixels, both of which are equal in size and aligned in position to improve system integration. The overall imaging system is a periodic repetition of this structure. To ensure that the superlens device is completely aligned with the pixels of the image sensor 9, the nanometer imprinting method is used in the super surface preparation process to ensure that the size and spacing of the superlens unit (i.e., the nanorod unit 21) are consistent.

[0072] Embodiment 1

[0073] As shown in Figure 1 and Figure 2 , the present embodiment 1 provides a fully integrated polarization imaging device of a polarization beam splitting superlens, which includes a nanorod array 2, a transparent medium substrate 3, and an image sensor 9.

[0074] The nanorod array 2 includes nanorod units 21, each of which is a rectangular column structure. The height (i.e., the size in the Z-axis direction) of the nanorod unit of the rectangular column structure is 800 nanometers to 1200 nanometers, the length range and the width range of the nanorod unit 21 are both 100 nanometers to 600 nanometers, and the array period is 700 nanometers. Each nanorod unit corresponds to two pixel regions of the image sensor, and the size of each pixel region is It should be noted that the size of the nanorod unit 21 and the number of nanorod units 21 can be adjusted according to actual imaging needs.

[0075] The transparent medium substrate 3 is made of silicon dioxide and has a thickness of 1 micrometer.

[0076] The image sensor 9 is mainly used for reading the image intensity information corresponding to different polarization states. The specific structure is as shown in Figure 1 and Figure 2As shown, from top to bottom are filter layer 4, photosensitive layer 5, circuit layer 6, substrate layer 7 and protective layer 8. Image sensor 9 has two pixel areas, each with a size of , and horizontal and vertical polarized light is focused to adjacent pixel areas.

[0077] In addition, the material of the rectangular column structure of nanocolumn unit 21 is selected from silicon nitride or titanium oxide , which has high transmittance and large refractive index in the visible light band. Figure 5 The transparent dielectric substrate 3 is silicon dioxide. By the finite difference time domain (FDTD) method, the period, height, width and length of the rectangular column structure of nanocolumn unit 21 in are scanned, and the transmittance and phase delay of electromagnetic waves are calculated under horizontal and vertical polarized incidence. At this time, not only the phase delay covers 0~2π, but also the phase delay amount covers the directional area of this parameter space, and the phase delay amount of the vertical polarization also covers the directional area of this parameter space. At the same time, in order to ensure the focusing efficiency of nanocolumn array 2 (i.e. polarization beam splitting superlens), the overall transmittance needs to exceed a certain threshold. The final determined super atom rectangular column height is 800nm to 1200nm, the length and width are 100nm to 600nm, and the period is 700nm. In order to facilitate process preparation, the super atoms on the same super surface have the same height, and the simulation results of the height of 1200nm are shown in . Figure 7

[0078] The phase template required by the superlens design is determined by the required function, and in the ideal case, the phase control formula of the polarization beam splitting superlens is:

[0079]

[0080] where are the required phase changes in the horizontal and vertical polarization directions, respectively, is the focal length of the superlens design, are the positions of the two focal points of the beam splitting, respectively. As in Figure 7 , for any design requirement (dark point), select the nearest point in the database (light point) as the length / width parameter combination, and the super surface that meets the requirements of the phase control formula for the overall phase distribution can be obtained, and the design steps are shown in Figure 8 .

[0081] The simulation results of the polarization beam splitting superlens are shown in Figure 9 . From Figure 9 ​The results show that the focal length and focal position of the polarization beam splitting superlens meet the design values, and the polarization beam splitting effect is achieved. The overall transmittance can reach 54.7%, and the polarization beam splitting ratio is more than 20:1. Compared with the traditional partition (two-way) polarization super surface, the extraction efficiency of single polarization state is improved by more than 1 times.

[0082] In some other embodiments, when the nanocolumn unit 21 is a polarization-independent superatom, the fully integrated polarization imaging device based on the polarization beam splitting superlens further comprises a multi-directional polarizer 13; the multi-directional polarizer 13 is arranged on the other side of the nanocolumn array 2 away from the transparent medium substrate 3, and is used for multi-directional polarization of the incident light beam to input multi-directional polarized light to the nanocolumn array 2.

[0083] In this embodiment, the nanocolumn unit 21 is a polarization-independent superatom, which can maintain consistent electromagnetic response under different polarized light, ensuring the stability and consistency of imaging. The multi-directional polarizer 13 performs multi-directional polarization on the incident light to provide multi-directional polarized light input to the nanocolumn array 2, enhancing the device's ability to capture different polarization states. Through the multi-directional polarizer 13, the device can simultaneously analyze light in multiple polarization directions, providing more comprehensive polarization information, which is suitable for complex polarization imaging tasks.

[0084] Further, the multi-directional polarizer 13 comprises a substrate; the substrate has a plurality of nanograting partitions; the nanograting partitions are arranged with polarizers; the polarization directions of the polarizers of the plurality of nanograting partitions are different. Each nanograting partition can independently control the polarization state of light, enhancing the clarity and details of imaging.

[0085] Further, the grating period of the nanograting partition is 110 nanometers to 160 nanometers, and the grating duty cycle is 0.3 to 0.7. Preferably, the grating period is 140 nanometers, and the grating duty cycle is 0.5.

[0086] Specifically, the polarizer is made of a metal nanograting super surface, and the substrate material is glass or other transparent dielectric material; the grating material is aluminum. The multi-directional polarizer 13 is composed of multiple groups of nanograting partitions with different polarization control directions, and can be designed as a two-way to six-way polarizer according to application requirements. The super surface multi-directional polarizer 13 can be fixed at the entrance pupil of the polarization imaging device by a mechanical device, or directly integrated above the superlens through a transparent medium such as silicon oxide, to ensure the integration of the device. The size of each nanograting partition corresponds to the pixel size of the image sensor, which can be the same, for example, The grating period is 140 nanometers, the duty cycle is 0.5, the grating line structure is straight, and the thickness is uniform.

[0087] Further, the polarization-independent superatom is a cylindrical structure. Optionally, the polarization-independent superatom has a size of 1000 nanometers to 1500 nanometers in the Z-axis direction, and a diameter of 150 nanometers to 500 nanometers. Within the range of 1000 nanometers to 1500 nanometers in height and 150 nanometers to 500 nanometers in diameter, the polarization-independent superatom can maintain consistent electromagnetic response under different polarized light, ensuring the stability and consistency of imaging. By precisely designing the height and diameter of the superatom, high-precision control of light is achieved, and the imaging resolution is improved. Each superatom can independently control the phase and amplitude of light, enhancing the clarity and details of the imaging.

[0088] Optionally, the height (i.e., the size in the Z-axis direction) of the polarization-independent superatom can be 1000 nanometers, can be 1500 nanometers, or can be any value between 1000 nanometers and 1500 nanometers.

[0089] Optionally, the diameter of the polarization-independent superatom can be 150 nanometers, can be 500 nanometers, or can be any value between 150 nanometers and 500 nanometers.

[0090] Embodiment 2

[0091] As shown in FIGS. 1A and 1B, the present embodiment 2 provides a fully integrated polarization imaging device based on polarization beam splitting superlenses. The fully integrated polarization imaging device based on polarization beam splitting superlenses includes a multi-directional polarizer 13, a nanocolumn array 2, a transparent dielectric substrate 3, and an image sensor 9. Figure 3 Figure 4 The polarizer is made of a metal nanograting super surface, and the base material is glass or other transparent dielectric material; the grating material is aluminum. The multi-directional polarizer is composed of multiple groups of nanograting sub-zones with different polarization control directions. According to application requirements, a two-way to six-way polarizer can be designed. The super surface multi-directional polarizer can be fixed at the entrance pupil of the polarization imaging device by a mechanical device, or directly integrated above the superlens by a transparent medium such as silicon oxide, to ensure the integration of the device. The size of each nanograting sub-zone corresponding to the pixel size of the image sensor can be the same, for example, 1 micrometer, the grating period is 140 nanometers, the duty cycle is 0.5, the grating line structure is flat, and the thickness is uniform.

[0092] The polarizer is made of a metal nanograting super surface, and the base material is glass or other transparent dielectric material; the grating material is aluminum. The multi-directional polarizer is composed of multiple groups of nanograting sub-zones with different polarization control directions. According to application requirements, a two-way to six-way polarizer can be designed. The super surface multi-directional polarizer can be fixed at the entrance pupil of the polarization imaging device by a mechanical device, or directly integrated above the superlens by a transparent medium such as silicon oxide, to ensure the integration of the device. The size of each nanograting sub-zone corresponding to the pixel size of the image sensor can be the same, for example, 1 micrometer, the grating period is 140 nanometers, the duty cycle is 0.5, the grating line structure is flat, and the thickness is uniform.

[0093] The nanocolumn array 2 includes nanocolumn units 21, the nanocolumn unit 21 is a cylindrical structure, the height (i.e., the size in the Z-axis direction) of the cylindrical structure nanocolumn unit 21 is 1000 nanometers to 1500 nanometers, the diameter of the nanocolumn unit 21 is 150 nanometers to 500 nanometers, and the array period is 500 nanometers. ​​Each nanopillar unit 21 corresponds to two pixel regions of the image sensor 9, and the size of each pixel region is [missing information]. It should be noted that the size and number of nanopillar units 21 can be adjusted according to actual imaging requirements.

[0094] The transparent dielectric substrate 3 is made of silicon dioxide and has a thickness of 1 micrometer.

[0095] Image sensor 9 is mainly used to read image intensity information corresponding to different polarization states. Its specific structure is as follows: Figure 3 and Figure 4 As shown, from top to bottom, the layers are: filter layer 4, photosensitive layer 5, circuit layer 6, substrate layer 7, and protective layer 8. The image sensor 9 has two pixel regions, each with a size of [missing information]. Horizontally polarized light and vertically polarized light are focused onto adjacent pixel areas, respectively.

[0096] Furthermore, the cylindrical nanopillar unit 21 is made of silicon nitride, which has high transmittance and high refractive index in the visible light band. Or titanium dioxide ( The transparent dielectric substrate is silicon dioxide. The finite-difference time-domain (FDTD) method is used to... Figure 6 The period, height, and diameter of the cylindrical nanopillar unit 21 were scanned, and the transmittance and phase delay of the electromagnetic wave were calculated under arbitrary polarization conditions. The final determined height of the cylindrical nanopillar unit 21 was 1000 nm to 1500 nm, the diameter was 50 nm to 150 nm, and the period was 500 nm.

[0097] In an ideal case, the phase modulation formula for a polarization-independent focusing superlens is:

[0098]

[0099] in This is the required phase change. Design the focal length for the superlens. The focal point is defined as [location]. By selecting a combination of radius and phase parameters from the database, a metasurface whose overall phase distribution satisfies the requirements of the phase control formula can be obtained. The design principle is the same as in Example 1.

[0100] The multi-directional polarizer 13 consists of multiple nanograting sections with different polarization control directions and a substrate. Depending on application requirements, bidirectional to six-directional polarizers can be designed (taking a horizontal / vertical bilinear polarizer as an example, such as...). Figure 3). Wherein the base material is selected as glass or other transparent dielectric material; the metal nanometer grating is selected as rectangular aluminum (Al) because it has the best comprehensive performance of maximum polarization transmittance and extinction ratio. The structural parameters of the grating are period 140 nanometers, duty cycle preferably 0.5, and grating depth can be 100 nanometers. The key parameter determining the performance of the grating (polarization transmittance and extinction ratio) is the relationship between the grating period and the wavelength of the incident light. When the grating period is greater than the wavelength of the incident light, the grating has multiple diffraction waves, at this time the grating can be used as a diffraction grating or a waveguide grating, but cannot be used as a polarizer. When the grating period is much smaller than the wavelength of the incident light, the grating has only zero-order diffraction wave, and the polarization is strong and can be used as a good polarizer. Therefore, the zero-order transmittance of the metal grating has a critical period point, and the critical period is almost linearly related to the wavelength. In order to make the visible light band meet the critical transmission condition, the period needs to be as small as possible, and 140 nanometers is selected as the grating period during preparation. The transmittance of the nanometer grating polarizer increases with the increase of the duty cycle, and the extinction ratio decreases with the increase of the duty cycle, and the optimal duty cycle is selected as 0.5. With the increase of the grating depth, the transmittance decreases and the extinction ratio increases, and the manufacturing process becomes more difficult. Considering comprehensively, the grating depth is selected as 100 nanometers. The super surface multi-directional polarizer is fixed above the super lens by a mechanical device, and the size of each nanometer grating partition corresponds to the pixel size of the image sensor, which is .

[0101] In summary, the image sensor reads the polarization information in different directions in a channel. In the polarization beam splitting super lens scheme of the above two embodiments, the CIS pixels collect horizontal / vertical linear polarization information in a channel. The CIS output image is reorganized in a channel to obtain independent horizontal and vertical polarization images, and the resolution loss is only 50% of the original image sensor. After interpolation algorithm processing, two polarization images with different polarization states and almost no resolution loss can be obtained simultaneously by a single image sensor. Compared with the current multi-channel Stokes polarization super surface scheme, the super lens layer uses the principle of space division multiplexing, and the theoretical resolution and single-channel polarization image intensity are improved by at least 1 times.

[0102] High integration of polarization imaging system: Compared with the traditional time-sharing, amplitude-sharing, aperture-sharing polarization imaging system, the full-integrated polarization imaging device based on polarization beam splitting superlens can directly cascade the polarization detection device in front of the image sensor without additional optical elements. Different from the six-pixel polarization information acquisition scheme used in the existing super surface-based polarization imaging system, the utility model proposes a two-pixel polarization imaging scheme with higher space utilization. The transparent medium substrate is multiplexed as a polarization light transmission layer and a connection layer of the nanometer column array and the CIS, and the overall polarization imaging system (excluding the image sensor) has a thickness of only microns, greatly widening the miniaturization and integration application scenarios. The image sensor pixel isolation receives different polarization signals, the detector has no pixel loss, and only one detector can realize real-time and multi-channel detection, with ultra-high integration.

[0103] Low polarization imaging loss and high resolution: The traditional six-pixel super surface polarization scheme needs to divide the super surface into six different polarization state light sensing areas, and the energy utilization rate of a single polarization state is extremely low. However, the superlens (embodiment 2) in the utility model adopts two-pixel imaging, and is only divided into two different polarization state light sensing areas. On the premise of ensuring the richness of polarization information, the energy loss is reduced by three times. Embodiment 1 further adopts the space division multiplexing principle, and each polarization state incident light does not have energy loss caused by filtering. The theoretical single-channel polarization image intensity is at least 1 times higher than that of embodiment 2, and the energy loss is much lower than that of the existing super surface scheme. The imaging resolution is extremely high, and the image sensor isolation outputs the polarization image. The resolution loss is only 50%. After the interpolation algorithm processing, the resolution is almost lossless, which is much higher than the existing polarization imaging scheme.

[0104] Adjustable working mode and expandable frequency band: Compared with the traditional six-pixel super surface polarization scheme which can only work in the polarization beam splitting scene, the utility model can also be applied to single polarization incident mode focusing, widening the application scenarios. The superlens has high design freedom, and can realize two-pixel to six-pixel superlens combination according to application requirements. The frequency band can be expanded. The super atom parameters can be adjusted by combining dispersion compensation and neural network optimization method, so as to realize the achromatic polarization beam splitting superlens in a wide waveband range.

[0105] Simple process flow and low cost: Different from the etching and other preparation methods of traditional optical elements and super surfaces, the utility model adopts the nanoimprint method to prepare the superlens, metal nanometer grating and other super surface structures. Only a unified preparation template is needed to realize large-scale transfer, which greatly improves the standardization, economy and universality of the polarization imaging system, and has high commercial value.

[0106] Finally, it should be noted that: the above examples are used to illustrate the technical solutions of the present application, but not limited to; although the present application is described in detail with reference to the foregoing examples, those skilled in the art should understand that: it can still be modified to the technical solutions recorded in the foregoing examples, or part of the technical features are replaced; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A fully integrated polarized imaging device based on polarization-splitting superlens, characterized in that, include: Nanopillar array (2); A transparent dielectric substrate (3) is provided with the nanopillar array (2) on one side of the transparent dielectric substrate (3); An image sensor (9) is disposed on the other side of the transparent medium substrate (3) away from the nanopillar array (2); the image sensor (9) has at least two pixel areas; the light beam output from the nanopillar array (2) is split and focused onto the pixel areas after passing through the transparent medium substrate (3).

2. The polarization splitter-holographic metasurface lens based fully integrated polar imaging device according to claim 1, wherein, The nanopillar array (2) includes: Multiple nanopillar units (21) are arranged in an array on one side of the transparent dielectric substrate (3); the nanopillar units (21) are polarization-dependent superatoms or polarization-independent superatoms.

3. The polarization splitter-hologram based full integrated polarized imaging device according to claim 2, wherein, The polarization-dependent superatoms have a rectangular columnar structure.

4. The polarization splitter-hologram based full integrated polarized imaging device according to claim 3, wherein, The polarization-dependent superatoms have a size of 800 nm to 1200 nm in the Z-axis direction, a size of 100 nm to 600 nm in the X-axis direction, and a size of 100 nm to 600 nm in the Y-axis direction.

5. The polarization splitter-hologram based ultrathin lens integrated polarized imager device according to claim 2, wherein, When the nanopillar unit (21) is the polarization-independent superatom, the fully integrated polarization imaging device based on the polarization beam-splitting superlens further includes: A multi-directional polarizer (13) is disposed on the other side of the nanopillar array (2) away from the transparent dielectric substrate (3) to multi-directionally polarize the incident light beam so as to input multi-directionally polarized light into the nanopillar array (2).

6. The polarization splitter-hologram based ultrathin lens integrated polarized imager device according to claim 5, wherein, The polarization-independent superatom has a cylindrical structure.

7. The polarization splitter-hologram based full integrated polarized imaging device according to claim 6, wherein, The polarization-independent superatom has a size of 1000 to 1500 nanometers in the Z-axis direction and a diameter of 150 to 500 nanometers.

8. The polarization splitter-holographic metasurface lens based fully integrated polar imaging device of claim 5, wherein, The multi-directional polarizer (13) includes: A substrate having multiple nanograting sections; polarizers arranged within each nanograting section; the polarizers of the multiple nanograting sections having different polarization directions.

9. The polarization splitter-hologram based full integrated polarized imaging device according to claim 8, wherein, The grating period of the nanograting partition is 110 nanometers to 160 nanometers, and the grating duty cycle is 0.3 to 0.

7.

10. The fully integrated polarized imaging device based on polarization splitting superlens according to any one of claims 1 to 9, characterized in that, The image sensor (9) includes: A filter layer (4) is connected to the transparent dielectric substrate (3) on the side facing the transparent dielectric substrate (3).

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