A multimodal imaging chip and method of fabrication

Abstract

The present application relates to the technical field of imaging chip, and particularly relates to a multi-modal imaging chip and a preparation method thereof; the multi-modal imaging chip, wherein each macro-pixel in a light modulation layer corresponds to a pixel cluster of an image sensing layer; each macro-pixel adopts an anti-crosstalk micro-nano structure primitive array; a plurality of polarization-independent spectral selection micro-nano units and a plurality of spectral-independent polarization selection micro-nano units are arranged in a non-uniform manner in each anti-crosstalk micro-nano structure primitive array; the polarization-independent spectral selection micro-nano unit is a two-dimensional grating structure with four-fold rotational symmetry, and based on a first preset parameter, selective modulation of light of a preset specific waveband is realized; the spectral-independent polarization selection micro-nano unit is a one-dimensional grating structure with anisotropy, and based on a second preset parameter, selective modulation of light of a specific polarization state is realized. The present application can decouple and reconstruct spectral information and polarization information of an incident light field from a single frame of image obtained by single exposure.

Description

Technical Field

[0001] This invention relates to the field of imaging chip technology, and more specifically to a multimodal imaging chip and its fabrication method. Background Technology

[0002] Hyperspectral imaging and polarization imaging technologies can capture information dimensions beyond those of traditional RGB images, and have wide applications in industrial inspection, remote sensing, and biomedical diagnostics. However, traditional imaging systems achieve their functions through a series of discrete optical elements such as gratings, filters, and polarizers, resulting in problems such as large size, complex structure, high cost, poor stability (susceptibility to vibration and thermal drift), and slow data acquisition speed.

[0003] In recent years, metasurface-based micro / nano optical devices have brought hope for miniaturization. However, existing designs mostly focus on single functions, such as focusing or spectral filtering only, or stacking metasurfaces with different functions, which introduces significant polarization-spectral crosstalk and fabrication difficulties. Currently, there is a lack of a snapshot-style integrated solution that can simultaneously achieve polarization-independent spectral modulation and spectral-independent polarization modulation on a single plane through a single-layer micro / nano structure, thereby enabling the synchronous acquisition of spatiotemporal spectral polarization images.

[0004] Therefore, there is an urgent need in this field for a polarization spectral imaging chip and its fabrication method that can solve the above-mentioned technical bottlenecks and achieve high performance, low cost, and miniaturization. Summary of the Invention

[0005] Therefore, the technical problem to be solved by the present invention is to overcome the defects existing in the prior art, thereby providing a multimodal imaging chip and its fabrication method.

[0006] A multimodal imaging chip includes, from top to bottom, an optical modulation layer, an image sensing layer, and a control processing module for processing received electrical signals and further reconstructing polarization and spectral images through calculation. The optical modulation layer consists of multiple periodically arranged macro pixels; each macro pixel corresponds to a pixel cluster in the image sensing layer; each macro pixel employs an anti-crosstalk micro / nano structure primitive array; the anti-crosstalk micro / nano structure primitive array consists of at least one polarization-independent spectrally selected micro / nano unit and one spectrally independent polarization selected micro / nano unit. Within each anti-crosstalk micro / nano structure element array, several polarization-independent spectral-selective micro / nano units and several spectral-independent polarization-selective micro / nano units are arranged alternately in a non-uniform manner; The polarization-independent spectral selection micro / nano unit is a two-dimensional grating structure with fourfold rotational symmetry, and based on the first preset parameters, it can selectively modulate light in a preset specific wavelength band. The spectrum-independent polarization-selective micro / nano unit is an anisotropic one-dimensional grating structure, and based on a second preset parameter, it achieves selective modulation of light with a specific polarization state.

[0007] Preferably, the lateral feature size of the polarization-independent spectrally selective micro / nano units and the spectrally independent polarization-selective micro / nano units is 0.5 μm to 5 μm; The structural depths of polarization-independent spectrally selected micro / nano units and spectrally independent polarization-selective micro / nano units range from 0.3 μm to 1.2 μm.

[0008] Preferably, any polarization-independent spectral selection micro / nano unit uses only one geometry and one size.

[0009] Preferably, any spectrum-independent polarization-selective micro / nano unit uses only one anisotropic structure.

[0010] Preferably, the difference in modulation efficiency between TE polarization and TM polarization of the polarization-independent spectral selection micro / nano unit within the preset target operating band is less than 5%.

[0011] Preferably, the change in polarization extinction ratio of the spectrally independent polarization-selective micro / nano unit within the preset target operating band is less than 3dB.

[0012] A method for fabricating a multimodal imaging chip, comprising: S1. Deposit a dielectric thin film on the photosensitive area of ​​the image sensing layer wafer; S2. Using photolithography and etching processes to fabricate polarization-independent spectral-selective micro / nano units and spectrally-independent polarization-selective micro / nano units in dielectric thin films; S3. Encapsulate the image sensing layer and the control processing module; The etching gas is a mixture of CF4, CHF3 and Ar.

[0013] Preferably, the dielectric thin film is a silicon nitride thin film with a thickness of approximately 1.0 μm and a refractive index of approximately 2.0 at a wavelength of 550 nm; the extinction coefficient k ≤ 1 × 10⁻⁶. -4 .

[0014] The technical solution of this invention has the following advantages: This invention provides a multimodal imaging chip and its fabrication method. This multimodal imaging chip achieves broadband polarization modulation and polarization-independent spectral modulation through micro / nano structural units of different shapes. It boasts high integration: integrating spectral and polarization modulation functions into a single-layer micro / nano structure, monolithically integrated with the CMOS image sensing layer, achieving extreme miniaturization. High performance: through the synergistic design of polarization-independent and spectral-independent technologies, the crosstalk problem is fundamentally solved, significantly improving the fidelity and signal-to-noise ratio of information extraction. High throughput: all optical information can be captured in a single exposure, eliminating the need for mechanical scanning or timing switching, making it suitable for dynamic scene detection. Mass production feasibility: the fabrication process is compatible with standard semiconductor processes, suitable for large-scale, low-cost manufacturing. Further practical applications can be combined with dynamic compensation systems and AI image processing to perform high-precision synchronous polarization and spectral detection in the visible light band under natural light environments. This invention is applicable to fields such as semiconductor microcrack detection, biomedical diagnosis, and remote sensing imaging, possessing advantages such as small size, high integration, and strong anti-interference capabilities. Attached Figure Description

[0015] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0016] Figure 1 This is a schematic cross-sectional view of the overall structure of the multimodal imaging chip; Figure 2 This is a schematic diagram of the macro-pixel arrangement of a multimodal imaging chip; Figure 3 A partially enlarged schematic diagram of a micro / nano structure element array for preventing crosstalk; Figure 4 This is a schematic diagram of the transmission spectrum of the first micro / nano unit A; Figure 5 This is a schematic diagram of the transmission spectrum of the first micro / nano unit B; Figure 6 This is a schematic diagram of the C transmission spectrum of the first micro / nano unit; Figure 7 This is a schematic diagram of the transmission spectrum of the first micro / nano unit D; Figure 8 This is a schematic diagram of the E-transmission spectrum of the first micro / nano unit; Figure 9 This is a schematic diagram of the spectral lines of the second micro / nano unit. Figure 10 This is a schematic diagram of the optical field response of the micro-nano unit cells of a multimodal imaging chip when the polarization angle is 0 degrees. Figure 11This is a schematic diagram of the optical field response of the micro / nano unit cells of a multimodal imaging chip when the polarization angle is 45 degrees. Figure 12 This is a schematic diagram of the optical field response of the micro / nano unit cells of a multimodal imaging chip when the polarization angle is 90 degrees. Figure 13 This is a schematic diagram of the optical field response of the micro / nano unit of the multimodal imaging chip when the polarization angle is 135 degrees. Figure 14 The true value of the intensity distribution of the test object in the simulation model input in Example 6 is used as a reference at a certain center wavelength; Figure 15 The results obtained in Example 6 using a multimodal imaging chip and reconstruction algorithm; Figure 16 The results are simulated and reconstructed using the traditional sequential measurement method.

[0017] Explanation of reference numerals in the attached figures: 1-Radiation source; 2-Optical modulation layer; 3-Image sensing layer; 4-Control and processing module; 200-Anti-crosstalk micro / nano structure element array; 201-First micro / nano unit A; 202-Second micro / nano unit A; 203-First micro / nano unit B; 204-Second micro / nano unit B; 205-First micro / nano unit C; 206-Second micro / nano unit C; 207-First micro / nano unit D; 208-Second micro / nano unit D; 209-First micro / nano unit E. Detailed Implementation

[0018] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0020] Example 1 To effectively suppress optical crosstalk between adjacent micro / nano units within the optical modulation layer 2 of a spatiotemporal spectral bias imaging chip through a specific arrangement, and to ensure the independence of the optical response of each micro / nano unit, this embodiment discloses an anti-crosstalk micro / nano structure primitive array 200. Figure 2-3 As shown; Specifically: In this embodiment, a crosstalk-resistant micro / nano structure element array 200 is composed of two types of functional units: spectrally independent polarization-selective micro / nano units and polarization-independent spectrally selective micro / nano units.

[0021] In terms of structural arrangement, each anti-crosstalk micro / nano structure element array 200 is composed of at least one spectrally independent polarization-selective micro / nano unit and one polarization-independent spectrally selected micro / nano unit. Within each anti-crosstalk micro / nanostructure array 200, several polarization-independent spectrally selected micro / nano units and several spectrally independent polarization-selective micro / nano units are arranged alternately in a non-uniform manner. Specifically, in this embodiment, a checkerboard alternating arrangement is used as an example. Figure 2-3 As shown, each polarization-independent spectrally selective micro / nano unit is surrounded by other polarization-independent micro / nano units, and vice versa. The polarization-independent spectrally selective micro / nano units have the same structural height H to ensure compatibility with a unified fabrication process.

[0022] To verify the performance of the anti-crosstalk array, optical simulation was performed using the finite difference time-domain method, and the results were compared with a periodic array composed entirely of the same type of micro-nano units.

[0023] Simulation results show that in traditional homogeneous arrays, the electric field enhancement regions at the edges of adjacent cells significantly overlap. However, in the checkerboard alternating array of this embodiment, the electric field energy is better confined within each cell.

[0024] Based on the simulation results, as follows Figure 4-13 As shown, in an alternating arrangement, the spectrally independent polarization-selective micro / nano units maintain their broadband flat polarization response, and the polarization-independent spectrally selected micro / nano units also maintain their polarization-independent spectral shape; their functions are not significantly distorted due to integration. The anti-crosstalk array effectively reduces near-field coupling between adjacent units, making the optical responses of each micro / nano unit more independent, significantly improving resonance characteristics, and achieving the design goal of suppressing optical crosstalk.

[0025] Example 2 To realize the function of the polarization-independent spectral selection micro / nano unit in Example 1, this embodiment further describes the polarization-independent spectral selection micro / nano unit used in Example 1: In this embodiment, the polarization-independent spectral selection micro / nano unit adopts a two-dimensional grating structure with fourfold rotational symmetry, thereby achieving insensitivity to changes in the wavelength of the polarization state of the incident light; and further, based on a first preset parameter, it achieves selective modulation of light in a preset specific wavelength band; Specifically: The polarization-independent spectral selection micro / nano unit includes a first substrate and a first metasurface array disposed on the first substrate; In this embodiment, the first metasurface array is a two-dimensional grating structure composed of multiple first micro / nano units. The first micro / nano units are made of single-crystal silicon and have a height of H. In this embodiment, the period P of the first metasurface array is equal in the X and Y axes. By employing first micro / nano units with rotational symmetry and a multi-size hybrid design, the structure's sensitivity to polarization direction is eliminated. Simultaneously, the superposition of structural size resonance peaks is utilized to form the target spectral response. The first micro / nano units can adopt structures including, but not limited to, cylindrical, square, and cross-shaped pillars. Figure 3 The first micro / nano unit A201, first micro / nano unit B203, first micro / nano unit C205, first micro / nano unit D207, and first micro / nano unit E209 are shown in the diagram. It should be noted that the first preset parameters should be set according to actual needs in practical applications. The first preset parameters include, but are not limited to, dimensional parameters such as diameter, height, and period. Furthermore, each polarization-independent spectral selection micro / nano unit uses only one geometry and one size. Additionally, for first micro / nano units with sharp edges, such as square prisms and cross prisms, rounded transitions or chamfered structures are provided at their edges. These rounded transitions or chamfered structures are used to suppress charge accumulation effects during etching and improve etching conformability.

[0026] To verify the performance of the first micro / nano unit in this embodiment, optical simulation was performed using the finite difference time-domain method.

[0027] During the simulation, the simulated light source was set as a plane wave with vertical incidence, and the spectral response under different polarization states was tested. The wavelength scanning range was from 400 nm to 1100 nm.

[0028] Simulation results are as follows Figure 4-8 As shown, the spectral response lines under different polarization states exhibit consistent trends, with a maximum deviation within 3%. Within the wavelength range of 400 nm to 1100 nm, the transmission spectrum curves under different polarizations essentially overlap, with the maximum difference in transmittance between the two not exceeding 5%.

[0029] According to the simulation results, the first micro-nano unit exhibits basically consistent spectral response characteristics to polarized light. Its transmission spectrum mainly depends on the incident light wavelength and is basically independent of the polarization state, thus realizing the polarization-independent spectral selection function.

[0030] Example 3 To achieve the functionality of the spectrally independent polarization-selective micro / nano unit in Example 1, and to match the scheme in Example 2, this example further describes the spectrally independent polarization-selective micro / nano unit: In this embodiment, the spectrum-independent polarization-selective micro / nano unit adopts an anisotropic one-dimensional grating structure, thereby achieving insensitivity to the wavelength of incident light; and further, based on a second preset parameter, it achieves selective modulation of light with a specific polarization state.

[0031] Specifically: The spectrally independent polarization-selective micro / nano unit includes a second substrate and a second metasurface array disposed on the second substrate; In this embodiment, the second metasurface array is a one-dimensional grating structure composed of multiple second micro / nano units. The structure of the second micro / nano units needs to be anisotropic, and in practical applications includes, but is not limited to, wire gratings and nanofins, such as... Figure 3 The second micro / nano unit A202, second micro / nano unit B204, second micro / nano unit C206, and second micro / nano unit D208 are shown in the diagram. The material and height of the second micro / nano unit are the same as those of the first micro / nano unit. Taking the wire grid structure as an example, the width of a single wire grid is W, the length is L, and the height is H. It should be noted that the second preset parameters are recommended to be set according to actual needs in practical applications. In this embodiment, polarization selection is achieved by utilizing the principle that the wire grid structure strongly interacts with the TM polarization component of the electric field parallel to its long axis, while having a weak effect on the TE polarization component of the orthogonal electric field. By designing the structural dimensions and resonant modes under specific parameters, its response remains stable over a wide wavelength range.

[0032] For example, optical simulations were performed using the finite difference time-domain method to verify the performance of the second micro / nano unit.

[0033] During the simulation, the simulated light source was set as a vertically incident linearly polarized plane wave with polarization directions of 0°, 45°, 90°, and 135°. The optical response at wavelengths of 400-1100 nm was measured, and the simulation results are as follows: Figure 9 As shown.

[0034] Simulation results show that the transmittance spectrum curve remains highly flat for a fixed polarization direction at different wavelengths. The second micro / nano unit exhibits stable polarization selectivity at different wavelengths, realizing a spectrum-independent polarization selectivity function.

[0035] Example 4 A multimodal imaging chip includes, from top to bottom, a light modulation layer 2, an image sensing layer 3, and a control processing module 4. For example... Figure 1 As shown, the radiation source 1 is incident on the light modulation layer 2. The image sensing layer 3 converts the light signal received from the light modulation layer 2 into an electrical signal, and further controls the exposure of the image sensing layer 3, reads the raw data, and runs a pre-trained information reconstruction algorithm through the control processing module 4 to calculate and output the Stokes polarization parameter map and spectral data cube of the target in real time.

[0036] Among them, such as Figure 2The light modulation layer 2 shown is composed of multiple periodically arranged macro pixels; each macro pixel corresponds to a pixel cluster of the image sensing layer 3; each macro pixel adopts the anti-crosstalk micro-nano structure primitive array 200 of Embodiment 1.

[0037] Furthermore, in this embodiment, the lateral feature size of the polarization-independent spectral-selective micro / nano unit in Example 2 and the spectral-independent polarization-selective micro / nano unit in Example 3 is 0.5 μm to 5 μm; the structural depth of the polarization-independent spectral-selective micro / nano unit and the spectral-independent polarization-selective micro / nano unit is 0.3 μm to 1.2 μm.

[0038] The difference in modulation efficiency between TE-polarized light and TM-polarized light by the polarization-independent spectral selection micro / nano unit within the preset target operating band is less than 5%.

[0039] The polarization extinction ratio of the spectrally independent polarization-selective micro / nano unit changes by less than 3 dB within the preset target operating band.

[0040] In summary, this multimodal imaging chip integrates multiple functional units into a metasurface array in a crosstalk-resistant manner, where each macropixel consists of multiple micro / nano units with different response characteristics. When a light field passes through this multimodal imaging chip, it is simultaneously modulated and imaged onto the detector. By combining advanced computational reconstruction algorithms, such as artificial intelligence algorithms, the spectral and polarization information of the incident light field can be decoupled and reconstructed from a single frame image acquired from a single exposure.

[0041] Example 5 This embodiment describes a method for fabricating a multimodal imaging chip. This method is compatible with standard semiconductor processes and is suitable for large-scale, high-consistency manufacturing of micro-nano units in Embodiments 1-3. It can realize monolithic integration of micro-nano optical structures and CMOS optoelectronic sensing circuits.

[0042] Specifically, it includes: Substrate preparation and coating: S0. Provide an optical-grade transparent substrate: In practical applications, the first and second substrates are identical. The selected materials include, but are not limited to, transparent materials such as quartz glass, sapphire, or fused silicon that meet the requirements for light transmission and structural support. For example, the thickness of the selected quartz glass is 0.5 mm. It should be noted that when using fused silicon, the purity must be greater than or equal to 99%. Multiple layers of high-contrast overlay alignment marks are pre-fabricated within the dicing area of ​​the substrate for overlay alignment between subsequent step-by-step photolithography steps.

[0043] S1. Deposit a dielectric thin film on the photosensitive area of ​​the image sensing layer 3 wafer: After cleaning and surface pretreatment of the substrate, a silicon nitride thin film is deposited on its surface as a dielectric film using plasma-enhanced chemical vapor deposition (PECVD).

[0044] For example, the deposition temperature is controlled at 300-350°C, the chamber pressure is 200-300 mTorr, and the reaction gases used include SiH4 and NH3.

[0045] The silicon nitride film has a thickness of approximately 1.0 μm, a refractive index of approximately 2.0 at a wavelength of 550 nm, and an extinction coefficient k ≤ 1 × 10⁻⁶. -4 .

[0046] For dielectric thin films, the structural material of the polarization-independent spectrally selective micro / nano units is single-crystal silicon, silicon nitride, or titanium dioxide. The preferred materials for the spectrally independent polarization selective micro / nano units are single-crystal silicon, metallic gold, silver, or aluminum wire grids.

[0047] It should be noted that the substrate is an inherent component of the image sensing layer 3. No modifications were made to the image sensing layer 3 in this case; it is a conventional design in the field. Therefore, the position of the substrate in the image sensing layer 3 and its relationship with other components will not be elaborated further. S2. Fabrication of polarization-independent spectrally selective micro / nano units and spectrally independent polarization-selective micro / nano units in a dielectric thin film using photolithography and etching processes: S201. First Photolithography: A first layer of photoresist is spin-coated onto the dielectric film and cured by pre-baking. Step-through projection lithography is employed, using a deep ultraviolet light source with high numerical aperture and off-axis illumination conditions to selectively expose small-sized grid regions, defining the pattern of spectrally independent polarization-selective micro / nano units. This pattern includes critical dimension test patterns and overlay accuracy marks located in the dicing groove or test area. After development, a photoresist mask with grid pattern openings is formed on the silicon nitride film surface. The overlay accuracy of the first photolithography is controlled to ≤20nm, supplemented by optical proximity correction to improve pattern fidelity.

[0048] S202. First Etching: Using the photoresist after the first photolithography as a mask, reactive ion etching (RIE) is employed to transfer the grid pattern into the silicon nitride layer, with an etching depth of H. A mixture of CF4, CHF3, and Ar is used as the etching gas. By adjusting the inductively coupled plasma power and bias power, the etching rate and sidewall morphology are precisely controlled. To address the rounding issue and micro-loading effect at the pattern corners, the flow rate ratio of CF4 or CHF3 is optimized, and the bias power is appropriately increased to enhance the directionality of ion bombardment, resulting in an etching morphology with steep sidewalls and smooth contours. After etching, the residual photoresist mask is removed, and the area is cleaned to obtain clean, spectrally independent polarization-selective micro / nano units.

[0049] S203. Second Photolithography: A second layer of photoresist is spin-coated onto the wafer with the first type of micro / nano units. Using pre-fabricated alignment marks in the dicing area, the pattern of the second photolithography is precisely aligned with the pattern etched in the first photolithography. Step-through projection lithography is employed, with selective exposure of the large-size spectral unit region under conventional illumination conditions to define the pattern of polarization-independent spectrally selected micro / nano units. After development, a photoresist mask with openings for the spectral unit pattern is formed on the surface of the silicon nitride thin film. The alignment accuracy of the second photolithography is controlled to ≤20nm, supplemented by optical proximity correction.

[0050] S204. Second Etching: Using the photoresist after the second photolithography as a mask, the spectral unit pattern is transferred to the silicon nitride layer under the same reactive ion etching conditions as the first etching, with the etching depth also being H. After etching, the residual photoresist mask is removed and the layer is cleaned to obtain clean polarization-independent spectral selectivity micro / nano units.

[0051] S205. Post-processing, integration, and testing: S2051. Wafer dicing: Dividing a wafer with a metasurface array into individual chips or modules.

[0052] S2052. Integration: A single chip or module is used as the optical modulation layer 2 and is integrated with the image sensing layer 3 wafer, which uses CMOS optoelectronic sensing circuits, through wafer bonding and flip-chip processes to achieve high-performance heterogeneous integration.

[0053] S3. The image sensing layer 3 and the control processing module 4 are encapsulated to protect the chip and provide an external interface.

[0054] S4. Test and verify the chip's electrical performance, reliability, and optical performance, such as transmission spectrum and polarization selectivity.

[0055] The multimodal imaging chip prepared by the above method achieves monolithic or heterogeneous integration of its optical micro-nano structure and CMOS optoelectronic sensing circuit in image sensing layer 3. The entire process flow is compatible with existing semiconductor manufacturing platforms, and monitoring graphics are provided for key steps, making it suitable for large-scale production and quality control.

[0056] Example 6 This embodiment provides a method for performing system-level performance simulation on the multimodal imaging chip prepared in Example 5, so as to quantitatively verify its effectiveness and advantages in acquiring spectral and polarization information in parallel under a single exposure.

[0057] In this embodiment, Monte Carlo ray tracing and information reconstruction algorithms are used to construct a complete forward imaging simulation model of the multimodal imaging chip to be simulated in the MATLAB software environment.

[0058] A comprehensive test scenario is set up in the simulation model. The test objects in the comprehensive test scenario include different regions, simulating the spectral curves of objects with specific spectral reflectance, such as green leaves and red flowers, and the combinations of polarization states with specific polarization characteristics, such as specular reflection and diffuse reflection, to comprehensively test the chip's multidimensional information perception capabilities.

[0059] The simulation process accurately simulates the process by which light passes through an optical system containing the imaging chip and generates an original grayscale image corresponding to the micro-nano unit channel on each pixel.

[0060] Based on the original grayscale image generated by simulation, a pre-trained artificial intelligence reconstruction algorithm, such as a deep learning-based decoupling network, is used to calculate and reconstruct the complete spectral information and Stokes polarization parameters of each point of the test object.

[0061] Reconstruction results as follows Figure 14-16 As shown. Figure 14 The true intensity distribution of the test object in the input simulation model at a certain center wavelength is displayed as a benchmark.

[0062] To ensure a fair comparison, two schemes were simulated under the same conditions of total incident light flux and total system acquisition time: Parallel acquisition scheme: Use a multimodal imaging chip for single-exposure imaging.

[0063] Traditional sequential measurement scheme: simulates the imaging process of multiple time-series exposures through an adjustable filter and a rotating polarizer.

[0064] Figure 15 The results obtained using a multimodal imaging chip and reconstruction algorithm are shown.

[0065] Visual comparison reveals that... Figure 15 The results and Figure 14 The truth values ​​are highly consistent, and the details are clear. And... Figure 16 The results showed obvious image blurring, loss of detail, and reconstruction distortion, demonstrating the limitations of traditional methods in terms of efficiency and information fidelity.

[0066] right Figure 15 and Figure 16 The reconstruction results were quantitatively analyzed, and their signal-to-noise ratio (SNR) was calculated. The analysis showed that, under the test conditions, the SNR of the reconstruction results from the present invention was 19.70 dB. Figure 15 The signal-to-noise ratio of the reconstruction result from the traditional sequential measurement scheme is 13.47 dB. Figure 16 .

[0067] For example, quantitative calculations show that the signal-to-noise ratio of the solution using this invention is improved by 46.3% compared to the traditional sequential measurement scheme. This significant improvement directly verifies the core advantages of this invention in improving the signal-to-noise ratio and measurement efficiency of multi-dimensional optical information acquisition systems through monolithic integration and parallel sensing.

[0068] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A multimodal imaging chip, characterized in that, It includes a light modulation layer (2) arranged from top to bottom, an image sensing layer (3), and a control processing module (4) for processing the received electrical signals and further reconstructing polarization and spectral images through calculation. Among them, the optical modulation layer (2) is composed of multiple periodically arranged macro pixels; each macro pixel corresponds to a pixel cluster of the image sensing layer (3); each macro pixel adopts an anti-crosstalk micro-nano structure primitive array (200); the anti-crosstalk micro-nano structure primitive array (200) is composed of at least one polarization-independent spectral selection micro-nano unit and a spectral-independent polarization selection micro-nano unit; Within each anti-crosstalk micro / nano structure element array (200), several polarization-independent spectral-selective micro / nano units and several spectral-independent polarization-selective micro / nano units are arranged alternately in a non-uniform manner; The polarization-independent spectral selection micro / nano unit is a two-dimensional grating structure with fourfold rotational symmetry, and based on the first preset parameters, it can selectively modulate light in a preset specific wavelength band. The spectrum-independent polarization-selective micro / nano unit is an anisotropic one-dimensional grating structure, and based on a second preset parameter, it achieves selective modulation of light with a specific polarization state.

2. The multimodal imaging chip according to claim 1, characterized in that, The lateral feature size of polarization-independent spectrally selective micro / nano units and spectrally independent polarization-selective micro / nano units ranges from 0.5 μm to 5 μm; The structural depths of polarization-independent spectrally selected micro / nano units and spectrally independent polarization-selective micro / nano units range from 0.3 μm to 1.2 μm.

3. The multimodal imaging chip according to claim 1, characterized in that, Any polarization-independent spectral selection micro / nano unit uses only one geometry and one size.

4. A multimodal imaging chip according to claim 1, characterized in that, Any spectrum-independent polarization-selective micro / nano unit uses only one anisotropic structure.

5. A multimodal imaging chip according to claim 1, characterized in that, The difference in modulation efficiency between TE polarization and TM polarization of the polarization-independent spectral selection micro / nano units within the preset target operating band is less than 5%.

6. A multimodal imaging chip according to claim 1, characterized in that, The polarization extinction ratio of the spectrally independent polarization-selective micro / nano unit changes by less than 3 dB within the preset target operating band.

7. A method for fabricating a multimodal imaging chip, characterized in that, include: S1. Deposit a dielectric thin film on the photosensitive area of ​​the image sensing layer (3) wafer; S2. Using photolithography and etching processes to fabricate polarization-independent spectral-selective micro / nano units and spectrally-independent polarization-selective micro / nano units in dielectric thin films; S3. Encapsulate the image sensing layer (3) and the control processing module (4); The etching gas is a mixture of CF4, CHF3 and Ar.

8. The method for fabricating a multimodal imaging chip according to claim 7, characterized in that, The dielectric thin film is a silicon nitride film with a thickness of approximately 1.0 μm and a refractive index of approximately 2.0 at a wavelength of 550 nm; the extinction coefficient k ≤ 1 × 10⁻⁶. -4 .

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