Mid-infrared multispectral integrated imaging system and method based on metasurface

Abstract

According to the mid-infrared multispectral integrated imaging device system and method based on the metasurface, superatom phase distribution is designed through dispersion engineering, accurate matching is conducted through a particle swarm optimization algorithm, incident light of different wavelengths generates transverse dispersion on a focal plane, full-wave-band spectral imaging can be completed through single exposure, and a mechanical scanning device is not needed. The quadruple rotational symmetry structure of the metasurface ensures the consistent response to TE / TM polarized light, and significantly improves the adaptability of the system in a complex polarization environment. The average energy utilization rate of the metasurface exceeds 50%, the highest isolation degree of each pixel is 48, and the metasurface has the characteristics of high signal-to-noise ratio and low crosstalk. Compared with a traditional spectral imaging device, the spectral imaging device has the advantages of being high in speed, high in energy utilization rate, small in size, low in crosstalk and the like, is suitable for application scenes such as medical endoscopy, industrial online detection and unmanned aerial vehicle environment monitoring which have high requirements for real-time performance and portability, and provides an innovative solution for achieving a miniaturized spectral imaging system.

Description

Technical Field

[0001] The present invention belongs to the field of nanophotonics and spectral imaging technology, and specifically relates to a mid-infrared multi-spectral integrated imaging system and method based on a metasurface. Background Art

[0002] Traditional imaging techniques can only capture the two-dimensional spatial intensity distribution of a target, but are unable to simultaneously analyze its spectral characteristics. This single-dimensional approach to information acquisition is no longer sufficient to meet the high-dimensional data demands of modern applications. Spectral imaging combines spatial and spectral resolution, providing continuous spectral information for each spatial pixel, significantly enriching the dimensionality of target features that can be captured. Infrared spectral imaging, in particular, can analyze specific spectral features, enabling non-destructive detection and quantitative analysis of material composition without contact or damage to the sample. This makes it crucial in medical diagnosis (e.g., tumor tissue identification), environmental monitoring (e.g., mapping atmospheric pollutant distribution), industrial quality inspection (e.g., polymer composition analysis), and military security (e.g., remote sensing of hazardous chemicals). However, achieving high-performance infrared spectral imaging still faces numerous technical challenges. While researchers have proposed solutions such as liquid crystal spatial light modulators, these systems require separate optical components (e.g., collimators, spectrometers, and detector arrays), resulting in low system integration and a struggle to meet the urgent demands of portable and embedded applications. In addition, the slow point-by-point scanning method cannot adapt to the real-time monitoring needs of dynamic scenes, which restricts the application of this technology on mobile platforms.

[0003] While liquid crystal spatial light modulators (LCSLMs) can achieve high spectral resolution, they have significant limitations in practical applications. While they offer advantages in electrical tuning, their spectral tuning range is limited by the birefringence of the liquid crystal material, and they generally operate only within a limited wavelength band. More critically, the slow response speed of liquid crystal molecules makes it difficult to meet the demands of high-speed dynamic spectral imaging. Furthermore, the strong absorption losses of liquid crystal materials in the mid-infrared band significantly restrict the application of these devices in this important spectral range. These issues make it difficult for existing technical solutions to meet the combined demands of modern spectral imaging for miniaturization, fast response, and wide-band operation.

[0004] As a new type of micro-nano light field control device, metasurfaces have shown significant potential in fields such as infrared spectral imaging due to their advantages such as ultra-thinness, high integration, and customizability, providing a new path to solving the miniaturization and real-time problems of traditional systems. As an artificially designed array of subwavelength structures, metasurfaces can realize the light field control functions required by traditional optical components within a thickness of the micron level. At the same time, metasurfaces can break through the volume limitations of traditional optical dispersive components and integrate functions such as splitting and focusing into ultra-thin planar devices. By carefully designing the geometric parameters and arrangement of nanostructures, researchers have realized a variety of metasurface spectral imaging devices with different functions, such as metasurface wavelength selection filters, dispersive spectroscopic metasurfaces, etc.

[0005] Currently, mid-infrared spectral imaging faces unique challenges. Due to the strong thermal radiation background, the signal intensity is several orders of magnitude lower than that of visible light, requiring the optical system to be extremely energy efficient. Furthermore, to meet practical application requirements, an optimal balance must be achieved between spatial, temporal, and spectral resolution. Summary of the Invention

[0006] Since the signal intensity in the infrared band is low and easily interfered by environmental noise, higher energy utilization, temporal resolution, spatial resolution and lower crosstalk are critical for mid-infrared spectral imaging. To this end, the first object of the present invention is to provide a mid-infrared multi-spectral integrated imaging system based on a metasurface. This design disperses light of different wavelengths laterally, and can capture full-spectral information simultaneously in a single snapshot without scanning or time-sharing measurement, significantly improving temporal resolution and energy utilization. Combined with wavelength-space coding, multi-band focusing can be formed on the focal plane to reduce signal crosstalk, while the pixel-level size takes into account spatial resolution. Efficient spectral coding is achieved at the hardware level, so that back-end calculations can quickly and accurately reconstruct spectral information and reduce data dependence. To this end, the above-mentioned purpose of the present invention is achieved through the following technical solutions:

[0007] A mid-infrared multispectral integrated imaging system based on a metasurface, comprising a pixel-level polarization-insensitive metasurface structure and a detector array.

[0008] The pixel-level polarization-insensitive metasurface structure consists of periodically arranged meta-atomic units and their substrates.

[0009] It is used to disperse the incident light laterally according to the wavelength and focus the dispersed light of different wavelengths to different spatial positions on the focal plane. The super-atom unit has C4 symmetry, and its symmetry axis is parallel to the direction of light propagation;

[0010] The meta-atom unit satisfies the equivalent refractive index model, and its phase distribution φ(x, y, ω) obeys the generalized Snell's law:

[0011] φ(x,y,ω)= +C(ω)

[0012] Where ω is the frequency of the light wave, c is the speed of light, (x, y) is the spatial coordinate of the metasurface, F is the focal length of the target, and C(ω) is the frequency-dependent function; θ and γ are the angular parameters of the incident direction, representing the angles between the projection of the light wave vector in the xz and yz planes and the optical axis, respectively; (x', y') is the spatial coordinate of the focus of the transmitted light with a frequency of ω in the target focal plane;

[0013] The detector array is located in the focal plane and is aligned with the metasurface structure at the pixel level to synchronously capture full-band spectral information. While adopting the above technical solutions, the present invention can also adopt or combine the following technical solutions:

[0014] As a preferred technical solution of the present invention: the super-atomic unit is a nanocolumn, which has four-fold rotational symmetry and is an all-silicon nanocolumn. The transmission phase is regulated by changing the geometric parameters of the nanocolumn to produce the same phase regulation effect on different polarizations.

[0015] As a preferred technical solution of the present invention: the base period P≈λ / 2, the arrangement is a square or regular hexagonal array, and the nanocolumn height H≈λ, where λ is the operating wavelength.

[0016] As a preferred technical solution of the present invention: the nanocolumns are cylindrical nanocolumns or regular polygonal nanocolumn structures.

[0017] As a preferred technical solution of the present invention: the pixel-level polarization-insensitive metasurface structure is designed by the following steps:

[0018] (1) Establish a meta-atom database: Calculate the transmittance and phase responses of meta-atoms with different geometric parameters in the target band using the finite-difference time-domain method;

[0019] (2) Phase distribution modeling: Based on parameters such as pixel size, working band, and target focal length, a full-surface phase template is generated according to the phase formula;

[0020] (3) Structural matching optimization: With the goal of minimizing the phase residual, the particle swarm algorithm is used to screen the optimal superatom combination from the superatom database, determine the superatom size at each spatial position, and form a pixel-level polarization-insensitive metasurface structure design.

[0021] The second object of the present invention is to provide an imaging method of a mid-infrared multi-spectral integrated imaging system based on a metasurface to address the problems in the prior art.

[0022] To this end, the above-mentioned purpose of the present invention is achieved through the following technical solutions:

[0023] The particle swarm optimization algorithm optimizes the pixel-level polarization-insensitive metasurface structure, achieving a spatial separation distance of different wavelengths of light in the focal plane greater than twice the pixel center distance in the 3-5μm mid-wave infrared band. Wavelength-space encoding is formed in the focal plane through lateral dispersion, and spectral information is obtained without mechanical scanning.

[0024] Polarization independence: The C4 symmetric structure makes the metasurface have the same response to TE / TM polarization.

[0025] High energy utilization and low crosstalk: average energy utilization > 50%, maximum isolation ratio of different pixels > 20.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] The present invention provides a mid-infrared multi-spectral integrated imaging system and method based on a metasurface, which achieves a breakthrough in infrared spectral imaging technology through the precise design of a super-atom array. The metasurface based on dispersion engineering has unique lateral dispersion characteristics, which can accurately spatially separate the incident light in the 3-5μm band, ensuring that the imaging point offset of different wavelengths on the focal plane exceeds 30μm, which is more than twice the detector pixel spacing. This design allows the system to complete the acquisition of full-band spectral data with only a single exposure, eliminating the traditional mechanical scanning structure. At the same time, the four-fold rotationally symmetric super-atom structure is polarization-independent and has the same response to TE and TM polarized light, which enables the system to maintain stable detection performance in complex polarization environments. In terms of energy efficiency, through the phase control optimization of the super-atom unit, the average energy utilization rate of the system exceeds 50%, and can reach up to 61.5%, which is much higher than the 25% energy utilization rate of traditional filters, significantly improving the signal-to-noise ratio and weak light detection capabilities. To achieve high-quality spectral analysis, the system uses a precise wavelength-space matching design, achieving a maximum isolation ratio of over 20 between bands, effectively suppressing spectral crosstalk. These features combine to form a new infrared spectral imaging device that combines high speed, high precision, miniaturization, and low power consumption. This provides an ideal solution for size- and weight-sensitive applications such as medical endoscopes and drone payloads. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 A schematic diagram of the mid-infrared multi-spectral integrated imaging device and its design structure based on a metasurface of the present invention;

[0029] Figure 2 Schematic diagram of the superatom design and optimization process in the present invention;

[0030] Figure 3 is the light intensity distribution of four pixels corresponding to the focal plane in four continuous bands in the present invention;

[0031] Figure 4 The energy collection efficiency of the four corresponding pixels on the focal plane varies with wavelength in the present invention;

[0032] Figure 5 The change of the isolation of the four corresponding pixels on the focal plane with wavelength in the present invention;

[0033] In the accompanying drawings, 1 is the metasurface structure; 2 is the focal plane pixel array. DETAILED DESCRIPTION

[0034] The implementation method, principle design and technical effects of the present invention are further described in detail below with reference to the accompanying drawings and specific embodiments.

[0035] A mid-infrared multispectral integrated imaging device and design based on a metasurface, comprising:

[0036] The pixel-level polarization-insensitive metasurface structure is composed of periodically arranged meta-atomic units, which is used to disperse the incident light laterally according to its wavelength and focus the dispersed light of different wavelengths to different spatial positions on the focal plane;

[0037] a detector array, located in the focal plane and registered with the metasurface structure at the pixel level, for synchronously capturing full-band spectral information;

[0038] The meta-atom unit satisfies the equivalent refractive index model, and its phase distribution φ(x, y, ω) obeys the generalized Snell's law:

[0039] φ(x,y,ω)= +C(ω)

[0040] Where ω is the light frequency, c is the speed of light, (x,y) is the spatial coordinate of the metasurface, F is the target focal length, and C(ω) is the frequency-dependent function. θ and γ are the angular parameters of the incident direction, representing the angle between the projection of the light wave vector in the xz and yz planes and the optical axis, respectively. (x',y') is the spatial coordinate of the focus of the transmitted light with frequency ω in the target focal plane.

[0041] While adopting the above technical solutions, the present invention may also adopt or combine the following technical solutions:

[0042] As a preferred technical solution of this invention: The superatomic unit is composed of an all-silicon nanopillar and a substrate. The nanopillar has four-fold rotational symmetry, also known as C4 symmetry. By changing the geometric parameters of the nanopillar, the transmission phase is controlled to produce the same phase control effect for different polarizations. The substrate period P ≈ λ / 2, and the array is arranged in a square or regular hexagonal shape. The nanopillar height H ≈ λ (λ is the operating wavelength).

[0043] The particle swarm optimization algorithm optimizes the pixel-level polarization-insensitive metasurface structure, achieving a spatial separation distance of different wavelengths of light in the focal plane greater than twice the pixel center distance in the 3-5μm mid-wave infrared band. Wavelength-space encoding is formed in the focal plane through lateral dispersion, and spectral information is obtained without mechanical scanning.

[0044] Polarization independence: The C4 symmetric structure makes the metasurface have the same response to TE / TM polarization.

[0045] High energy utilization and low crosstalk: average energy utilization > 50%, maximum isolation ratio of different pixels > 20.

[0046] The design method of the metasurface structure comprises the following steps:

[0047] (1) Establishing a meta-atom database: Using the finite-difference time-domain (FDTD) method, the transmittance response and phase response of meta-atoms with different geometric parameters in the target band are calculated to construct a phase library;

[0048] (2) Phase distribution modeling: Based on parameters such as pixel size, working band, and target focal length, a full-surface phase template is generated according to the phase formula;

[0049] (3) Structural matching optimization: With the goal of minimizing phase residuals, the particle swarm algorithm is used to select the optimal superatom combination from the superatom database. The superatom size at each spatial position is determined to form a metasurface design.

[0050] The present invention has the following beneficial effects:

[0051] This invention achieves a breakthrough in infrared spectral imaging technology through the precise design of a meta-atom array. The dispersion-engineered metasurface possesses unique lateral dispersion properties, enabling precise spatial separation of incident light in the 3-5μm band, ensuring that the imaging points of different wavelengths on the focal plane are offset by more than 30μm, more than twice the detector pixel pitch. This design enables the system to acquire full-band spectral data with a single exposure, eliminating the need for traditional mechanical scanning structures. Furthermore, the four-fold rotationally symmetric meta-atom structure is polarization-independent, with identical responses to TE and TM polarized light. This enables the system to maintain stable detection performance even in complex polarization environments. In terms of energy efficiency, through phase control optimization of the meta-atom units, the system's average energy utilization exceeds 50%, reaching a maximum of 61.5%, far exceeding the 25% energy utilization of traditional filters, significantly improving the signal-to-noise ratio and low-light detection capabilities. To achieve high-quality spectral resolution, the system employs a precise wavelength-space matching design, resulting in a maximum isolation ratio between bands exceeding 20, effectively suppressing spectral crosstalk. These features together form a new type of infrared spectral imaging device that combines high speed, high precision, miniaturization and low power consumption. It provides an ideal solution for medical endoscopes, drone payloads and other fields that are sensitive to size and weight.

[0052] Example 1

[0053] This invention utilizes a lateral dispersion metasurface design to manipulate the dispersion properties of light waves, achieving efficient spectral information capture and optimized energy allocation within a single exposure. This overcomes the limitations of conventional technologies, which struggle to simultaneously achieve high energy efficiency, temporal resolution, and spatial resolution. Specifically, this approach: 1) decouples spectral and spatial information by leveraging the multidimensional controllability of the metasurface's subwavelength structure; 2) enables parallel detection of a wide spectrum band through lateral dispersion; and 3) utilizes a polarization-independent design to ensure spectral dispersion stability in multiple polarization states.

[0054] The metasurface design method is as follows:

[0055] A metasurface is composed of periodically arranged metaatoms, each of which can be considered a waveguide with an effective refractive index neff, whose magnitude depends solely on the metaatom's parameters. To ensure the metasurface's ability to produce stable dispersion for light of any polarization, the metaatoms employ a four-fold rotational symmetry (C4 symmetry) structure, making their phase modulation independent of the polarization state of the incident light, thereby enabling consistent control of light of varying polarizations. The nanopillars are typically arranged with a period P, equivalent to half a wavelength, and a height H, equivalent to the operating wavelength. The transmission phase characteristics of metaatomic units with varying structural parameters at specific wavelengths are calculated using the finite-difference time-domain method. By scanning the wavelength of the input light wave, the phase shift response of the metaatomic structure is recorded, and a metaatom database is constructed.

[0056] The target phase distribution is achieved by adjusting the diameter of the nanopillars, and its phase distribution φ(x, y, ω) obeys the generalized Snell's law.

[0057] The meta-atom unit satisfies the equivalent refractive index model. For each dispersive metasurface, according to the generalized Snell's law, the phase distribution at any position on the metalens must satisfy the following relationship:

[0058] φ(x,y,ω)= +C(ω)

[0059] Where (x, y) are the spatial coordinates on the metasurface, and c is the speed of light. The metasurface device precisely designs the phase distribution in the spatial domain (x, y) so that incident light of different frequencies ω forms positional dispersion on the focal plane at the focal length F. θ and γ are angular parameters of the incident direction, representing the angles between the projections of the light wave vector on the xz and yz planes and the optical axis, respectively. (x', y') are the spatial coordinates of the focus of the transmitted light of frequency ω on the target focal plane, where x'(ω), y'(ω), and C(ω) are functions that depend solely on frequency. By optimizing x'(ω) and y'(ω), the transmitted light is separated by wavelength and converged to different locations. This allows light of different wavelengths to separate and converge on the focal plane according to a preset dispersion relation, achieving decoupling of spectral and spatial information.

[0060] The designed dispersive metasurface has a diameter D, focal length F, incident angle θ, an operating wavelength range of 3-5µm, and a detector pixel center distance of 15µm. Substituting these parameters into the phase distribution formula yields the desired phase distribution for the metasurface. By formulating a reasonable loss function, a particle swarm optimization algorithm is used to select the metaatom structure with the smallest deviation from the target phase distribution to determine the overall metasurface structure.

[0061] Using meta-atom simulations with a phase distribution, a targeted spectral dispersion metasurface was designed. Through the metasurface's dispersion, four-band focusing was achieved while maintaining high energy collection efficiency and isolation ratio.

[0062] Example 2

[0063] like Figure 1 As shown, the infrared spectral imaging device provided by the present invention primarily consists of a metasurface structure 1 and a focal plane pixel array 2. The metasurface structure 1 is composed of periodically arranged silicon nanorods, with each meta-atomic unit modulating the phase of 3-5μm infrared waves by transmitting phase. The metasurface is distributed along the xy plane. Incident light with arbitrary polarization states carrying spectral information is modulated by the metasurface, and incident light of different wavelengths is directed and focused onto different regions, forming a wavelength-dependent lateral dispersion distribution on the focal plane 2.

[0064] like Figure 2 As shown, the present invention provides a mid-infrared multi-spectral integrated imaging device based on a metasurface, a design thereof, and an optimization design method thereof, which realizes efficient spectral splitting in the 3-5μm band through a systematic design process. First, a mathematical model of the metasurface phase distribution is established based on the generalized law of refraction and reflection to determine the target offset position of incident light of different wavelengths on the focal plane. At the same time, a silicon nanocolumn superatom structure with C4 symmetry is designed, and the phase response database of superatoms with different geometric parameters in the target band is calculated by the time-domain finite difference method. Then, the optimal superatom combination is screened from the superatom database by the particle swarm algorithm. The size of the superatom at each spatial position is determined to form a metasurface design. Finally, the optical responses of the four bands are simulated, and the imaging performance on the focal plane is analyzed.

[0065] like Figure 3 Figure 2 demonstrates the four-color imaging effect of the present invention. The intensity distribution of the focal plane is simulated for incident light over a wide spectral range, with wavelengths ranging from 4.7µm to 5µm, 4µm to 4.6µm, 3.4µm to 3.9µm, and 3µm to 3.3µm. Pixels are distinguished by dashed lines and shading. Incident light within four consecutive subbands is focused onto four distinct regions on the focal plane, corresponding to four pixels. There is only slight crosstalk at pixel boundaries, assuming a pixel center-to-center distance of 15µm.

[0066] like Figure 4 The figure shows the energy collection efficiency of the four pixels of the present invention. Solid lines of different colors correspond to different pixels, and the total energy collection efficiency of the four pixels is represented by the green dashed line. Energy collection efficiency is defined as the ratio of the light power transmitted through a pixel to the light power incident on the metasurface. At 3 to 5µm, the peak efficiencies at the four pixels are 27.835%, 52.461%, 61.502%, and 49.496%, respectively, with an average efficiency of 54.52%. This represents an improvement of more than two times compared to traditional narrowband filtering devices, significantly enhancing the system's signal-to-noise ratio and low-light detection capabilities.

[0067] like Figure 5 The figure shows the isolation of the four pixels of the present invention. Isolation is defined as the ratio of the optical power transmitted through the target pixel to the average optical power transmitted through the other three pixels. The peak isolation ratio of the four sub-bands is at least 20 and reaches a maximum of 48, effectively suppressing spectral crosstalk.

[0068] The present invention provides a mid-infrared multi-spectral integrated imaging device and design method based on a metasurface. The device utilizes dispersion engineering to design the meta-atom phase distribution, and uses a particle swarm optimization algorithm for precise matching, so that incident light of different wavelengths produces lateral dispersion in the focal plane. A single exposure can complete full-band spectral imaging without the need for a mechanical scanning device. The four-fold rotational symmetry of the metasurface ensures a consistent response to TE / TM polarized light, significantly improving the adaptability of the system in complex polarization environments. According to simulation calculations, the average energy utilization rate of the metasurface exceeds 50%, and the isolation degree of each pixel is up to 48, with high signal-to-noise ratio and low crosstalk characteristics. Compared with traditional spectral imaging devices, the present invention has the advantages of high speed, high energy utilization, miniaturization and low crosstalk. It is suitable for medical endoscopy, industrial online detection, drone environmental monitoring and other application scenarios with high requirements for real-time and portability, providing an innovative solution for the realization of miniaturized spectral imaging systems.

[0069] The above-mentioned specific implementation methods are used to illustrate the present invention and are only preferred embodiments of the present invention, rather than limiting the present invention. Any modifications, equivalent substitutions, improvements, etc. made to the present invention within the spirit of the present invention and the scope of protection of the claims shall fall within the scope of protection of the present invention.

Claims

1. A mid-infrared multispectral integrated imaging system based on a metasurface, characterized in that: Including pixel-level polarization-insensitive metasurface structures and detector arrays, The pixel-level polarization-insensitive metasurface structure consists of periodically arranged meta-atomic units and their substrates. It is used to disperse the incident light laterally according to the wavelength and focus the dispersed light of different wavelengths to different spatial positions on the focal plane. The super-atom unit has C4 symmetry, and its symmetry axis is parallel to the direction of light propagation; The meta-atom unit satisfies the equivalent refractive index model, and its phase distribution φ(x, y, ω) obeys the generalized Snell's law: φ(x,y,ω)= +C(ω) Where ω is the frequency of the light wave, c is the speed of light, (x, y) is the spatial coordinate of the metasurface, F is the focal length of the target, and C(ω) is the frequency-dependent function; θ and γ are the angular parameters of the incident direction, representing the angles between the projection of the light wave vector in the xz and yz planes and the optical axis, respectively; (x', y') is the spatial coordinate of the focus of the transmitted light with a frequency of ω in the target focal plane; The detector array, located in the focal plane, is aligned with the metasurface structure at the pixel level for synchronously capturing full-band spectral information.

2. The mid-infrared multispectral integrated imaging system based on a metasurface according to claim 1, characterized in that: The super-atom unit is a nanocolumn having four-fold rotational symmetry and being an all-silicon nanocolumn. The transmission phase is regulated by changing the geometric parameters of the nanocolumn to produce the same phase regulation effect for different polarizations.

3. The mid-infrared multispectral integrated imaging system based on a metasurface according to claim 2, characterized in that: The nanocolumn is a cylindrical nanocolumn or a regular polygonal nanocolumn structure, and the nanocolumn height H≈λ, where λ is the operating wavelength.

4. The mid-infrared multispectral integrated imaging system based on a metasurface according to claim 2, wherein: The base period P≈λ / 2, and the super-atomic units are arranged in a square or regular hexagonal array, where λ is the operating wavelength.

5. The mid-infrared multispectral integrated imaging system based on a metasurface according to claim 1, wherein: The pixel-level polarization-insensitive metasurface structure is designed by the following steps: (1) Establish a meta-atom database: Calculate the transmittance and phase responses of meta-atoms with different geometric parameters in the target band using the finite-difference time-domain method; (2) Phase distribution modeling: Based on parameters such as pixel size, working band, and target focal length, a full-surface phase template is generated according to the phase formula; (3) Structural matching optimization: With the goal of minimizing the phase residual, the particle swarm algorithm is used to screen the optimal superatom combination from the superatom database, determine the superatom size at each spatial position, and form a pixel-level polarization-insensitive metasurface structure design.

6. The imaging method of the metasurface-based mid-infrared multispectral integrated imaging system according to any one of claims 1 to 5, characterized in that: A particle swarm optimization algorithm was used to optimize the selection of C4-symmetric metaatoms, achieving single-exposure spectral capture in the 3-5μm mid-wave infrared band. By manipulating the metasurface structure, light of different wavelengths produces a spatial dispersion greater than twice the pixel center distance in the focal plane, forming wavelength-space encoding. This allows spectral information to be acquired without mechanical scanning, and its rotationally symmetric structure ensures consistent response to TE / TM polarized light. The particle swarm optimization algorithm optimizes the pixel-level polarization-insensitive metasurface structure, achieving a spatial separation distance of more than twice the pixel center distance at the focal plane for light of different wavelengths in the 3-5μm mid-wave infrared band. Lateral dispersion forms wavelength-space encoding at the focal plane, eliminating the need for mechanical scanning to obtain spectral information. Polarization independence: The C4 symmetric structure makes the metasurface have the same response to TE / TM polarization; High energy utilization and low crosstalk: average energy utilization > 50%, maximum isolation ratio of different pixels > 20.

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