Super-simple laser seeker optical system based on super-structure surface and construction method of super-simple laser seeker optical system

Abstract

The invention discloses a super-structure surface-based extremely-simple laser seeker optical system and a construction method thereof, and relates to the technical field of laser seekers. The optical system comprises a fairing, a diaphragm and a super-structure lens, the fairing is located on the leftmost side of the whole optical system, the fairing has negative focal power, the diaphragm is located between the fairing and the super-structure lens, the two sides of the super-structure lens are plated with a light filtering film and an antireflection film respectively, the light filtering film is located on the substrate on the side, without the nano-structure, of the super-structure lens, and the antireflection film is located on the substrate on the side, without the nano-structure, of the super-structure lens. The antireflection film is located on the side, provided with the nano structure, of the super-structure lens, and the super-structure lens has positive focal power. Compared with an existing laser seeker, the laser seeker has the advantages that the size, the weight and the price are remarkably optimized, and a new direction is provided for future development of guided weapons.

Description

Technical Field

[0001] The present invention belongs to the technical field of laser seeker, and more specifically, relates to a minimalist laser seeker optical system based on metasurface and a construction method thereof. Background Art

[0002] Laser guidance technology is an important part of modern precision-guided weapons, and its background technology stems from the extensive application of laser technology in the military field. Since laser technology was first introduced into the military field in 1960, technologies such as laser ranging and target indication have developed rapidly, significantly improving the combat accuracy. Its core principle is to use a laser illuminator on the ground or on an aircraft to continuously irradiate the target, and the laser seeker on the missile receives the laser signal reflected from the target, corrects the flight trajectory through signal processing and the guidance system, and finally accurately hits the target. Among them, the laser seeker mainly consists of three parts, namely an optical system, a quadrant detector, and a signal processing circuit.

[0003] Currently, there are mainly three forms of laser seeker optical systems: reflective, refractive, and catadioptric. Although the reflective system can fold the optical path to save axial space, it has a central obstruction, which will weaken the total light flux of the optical system and increase the difficulty of alignment at the same time; the catadioptric optical system requires the reflector to bear the optical power requirement and corrects the aberration with a refractive lens. This system has fewer optical elements and a smaller volume, but it will generate stray light, light blocking, a smaller field of view, and usually requires aspherical surfaces; for the refractive type, if a large-field-of-view and high-precision imaging optical system is to be realized, multiple spherical lenses are required, increasing the complexity of manufacturing and processing, introducing errors multiple times and thus affecting the accuracy, or introducing aspherical structures resulting in expensive processing costs and increased costs. In contrast, the laser seeker based on metasurface has been significantly optimized in terms of volume, weight, and price. First of all, the metasurface seeker can increase the fuel reserve and the efficiency of the propulsion system by saving space. At the same time, the lightweight seeker is conducive to the compactness and optimization of the overall structure of the missile, thereby improving the acceleration and flight speed, enhancing the system reliability, and simplifying the installation and commissioning process. This not only improves the maneuverability and range of the guided weapon, but also makes its structure simpler and more compact. In addition, the metasurface seeker reduces the number of lenses, thereby reducing the costs of manufacturing, testing, assembling, and aligning in the production process. The processing technology of metasurface (such as lithography, direct writing) usually adopts large-scale planar processing technology, which is more economical than the production technology of traditional curved optical elements (such as precision grinding, polishing). This technology not only reduces the possibility of loss and human error, but also reduces the overall cost and improves the manufacturing accuracy. In summary, the laser seeker based on metasurface significantly improves the performance and economy through optimized design and advanced manufacturing technology, providing a new direction for the future development of guided weapons. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a minimalist laser seeker optical system based on a metasurface and a method for constructing the same. The optical system has only one metasurface, and the metasurface can be batch-fabricated using semiconductor processes. Compared with the prior art, the optical system has the characteristics of smaller volume, lighter weight, and lower cost.

[0005] To solve the above technical problems, the technical solution adopted by the present invention is as follows: The minimalist laser seeker optical system based on a metasurface includes a radome, a diaphragm, and a metasurface lens. The radome is located at the leftmost side of the entire optical system, the diaphragm is located between the radome and the metasurface lens, and filter films and antireflection films are respectively coated on both sides of the metasurface lens. The filter film is located on the substrate on the side of the metasurface lens without nanostructures, and the antireflection film is located on the side of the metasurface lens with nanostructures. The laser first passes through the radome, whose function is to collect light rays in different fields of view. After the light rays pass through the diaphragm, the effective aperture of the light beam is restricted, the light passing amount and the numerical aperture of the system are controlled, and the range and direction of the propagating light rays are limited. Then the light rays pass through the metasurface lens, and wavefront modulation is achieved through the phase mutation generated by the subwavelength structures at the interface, realizing the functions of focusing and reducing aberration, thereby improving the focusing effect and imaging quality of the light beam. The two reasonably distribute the optical power and correct the aberration, achieving a better optical path folding. The combination of positive and negative optical powers can better control spherical aberration, and the use of metasurface elements can correct and eliminate higher-order aberrations, giving full play to the advantages of the two elements and realizing the design of the minimalist laser seeker optical system.

[0006] The content of the method for constructing a minimalist laser seeker optical system based on metasurface is as follows: The first step is to construct a model in ZEMAX and set some basic parameters, such as entrance pupil diameter, field of view, wavelength, material, etc. The surface shape of the radome can be spherical or aspherical, and the material can be K9 glass, zinc sulfide or zinc selenide. The material type can be two of the above examples but is not limited to these two. The materials of the filter film and the antireflection film can be zinc sulfide or zinc selenide. The material type can be two of the above examples but is not limited to these two, and it can also be a film system composed of multiple materials stacked. The second step is to set the optimization objectives, such as parameters like the metasurface area and the angle of incidence on the filter surface, and optimize the entire system. The third step is the preliminary viewing of the simulation structure. The specific indicators to be concerned about are parameters such as the spot diagram, ray trace diagram, maximum energy fluctuation of physical optical propagation, and the difference in geometric encircled energy. If the results meet the requirements, then in the fourth step, extract the coefficients of the binary surface and obtain the phase values at various positions of the metasurface. If the results do not meet the requirements, return to the previous step for iterative optimization until the requirements are met. The fifth step is to scan different nanostructure units to obtain the equivalent refractive index or phase values under different structural parameters and construct a database. The cross-sectional shape of the nanostructure unit can be a centrosymmetric structure, such as a circle, square or other combined figures, or a non-centrosymmetric structure such as a rectangle or ellipse. The structural shapes include the above examples but are not limited to these. In addition, the substrate and structural material of the metalens can be K9 glass and silicon respectively, but are not limited to this. The sixth step is to match the structure according to the obtained metasurface phase distribution to obtain the layout of the entire metasurface. The seventh step is to simulate indicators such as the focusing result, focusing efficiency, and transmittance of the metasurface in MATLAB. The last step is to bring the designed metasurface back into the ZEMAX system and view the results such as focal length, spot diagram, ray trace diagram, physical optical propagation, and encircled energy.

[0007] The beneficial effects of adopting the above technical solutions are as follows: Compared with the existing design and preparation schemes of laser seekers, the laser seeker based on metasurfaces has been significantly optimized in terms of volume, weight, and price. First of all, by saving space, the metasurface seeker can increase the fuel reserve and the efficiency of the propulsion system. At the same time, the lightweight seeker is conducive to the compactness and optimization of the overall structure of the missile, thereby improving the acceleration and flight speed, enhancing the system reliability, and simplifying the installation and commissioning process. This not only improves the maneuverability and range of the guided weapon, but also makes its structure simpler and more compact. Secondly, the metasurface seeker reduces the number of lenses, thereby reducing the costs of manufacturing, testing, assembling, and alignment during the production process. The processing technologies of metasurfaces (such as lithography and direct writing) usually adopt large-scale planar processing techniques, which are more economical than the production processes of traditional curved optical elements (such as precision grinding and polishing). This technology not only reduces the possibility of loss and human error, but also reduces the overall cost and improves the manufacturing accuracy. In summary, the laser seeker based on metasurfaces significantly improves the performance and economy through optimized design and advanced manufacturing technologies, providing a new direction for the future development of guided weapons. Brief Description of the Drawings

[0008] Figure 1 is the design flow chart of the optical system;

[0009] Figure 2 is the 2D layout diagram of the optimized system in Embodiment 1;

[0010] Figure 3 is the spot diagram of different fields of view in Embodiment 1;

[0011] Figure 4 is the ray trace diagram of all fields of view in Embodiment 1;

[0012] Figure 5 is the physical optical propagation energy distribution of all fields of view in Embodiment 1;

[0013] Figure 6 is the geometric encircled energy of the 0-9° field of view in Embodiment 1;

[0014] Figure 7 is the phase distribution diagram of the metasurface lens in Embodiment 1;

[0015] Figure 8 is the phase matching result in Embodiment 1;

[0016] Figure 9 is the layout of part of the metasurface lens in Embodiment 1;

[0017] Figure 10 is the 2D layout diagram of the optimized system in Embodiment 2;

[0018] Figure 11 is the spot diagram of different fields of view in Embodiment 2;

[0019] Figure 12 is the ray trace diagram of all fields of view in Embodiment 2;

[0020] Figure 13 is the physical optical propagation energy distribution of all fields of view in Embodiment 2;

[0021] Figure 14 is the geometric encircled energy of the 0 - 9° field of view in Embodiment 2;

[0022] Figure 15 is the phase distribution diagram of the metasurface lens in Embodiment 2;

[0023] Figure 16 is the phase matching result in Embodiment 2;

[0024] Figure 17 is the layout of part of the metasurface lens in Embodiment 2; Detailed implementation manners

[0025] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without making creative efforts belong to the scope of protection of the present application.

[0026] The optical system includes a radome, a diaphragm, and a metasurface lens. The radome is located at the leftmost side of the entire optical system. The diaphragm is located between the radome and the metasurface lens. Filter films and antireflection films are respectively coated on both sides of the metasurface lens. The filter film is located on the substrate on the side of the metasurface lens without nanostructures, and the antireflection film is located on the side of the metasurface lens with nanostructures.

[0027] Specific Embodiment 1 (the radome surface type is spherical):

[0028] Step 1: Build a model in ZEMAX, set the entrance pupil diameter to 16 mm, the central wavelength to 1064 nm, the field of view range to 0° - 16°, and the surface types from left to right are standard surface, standard surface, standard surface, diaphragm standard surface, standard surface, binary surface 2, and image surface standard surface.

[0029] Here, the fairing is crescent-shaped with a negative focal power. Its object side is convex and its image side is concave, and both the object side and the image side are standard surfaces. The metasurface lens has a positive focal power. Its object side is flat and its image side is a diffractive surface, with the nano-column structures arranged periodically. For light rays in different fields of view along the optical axis from the object side to the image side, they first pass through the fairing, whose function is to collect light rays in different fields of view. After passing through the aperture stop, the effective aperture of the light beam is constrained, controlling the light throughput and the numerical aperture of the system, and restricting the range and direction of the propagating light rays. Then the light rays pass through the metasurface lens, and wavefront modulation is achieved through the phase mutation generated by the sub-wavelength structure at the interface, realizing the functions of focusing and reducing aberration, thereby improving the focusing effect and imaging quality of the light beam. The fairing and the metasurface lens reasonably distribute the focal power and achieve aberration correction, realizing a better folding of the optical path. The combination of positive and negative focal powers can better control spherical aberration, and the use of metasurface elements can correct and eliminate higher-order aberrations, giving full play to the advantages of the two elements and realizing the design of a minimalist laser seeker optical system.

[0030] Step 2: Set the optimization target of the focal length to 16 mm, the size of the metasurface to 20 mm, and the maximum angle of incidence on the filter film surface to 20° in the evaluation function editor, and optimize the entire system. Figure 2-3 Figure 5 is the 2D layout diagram of the entire system after optimization. The optimized front surface curvature radius of the fairing is 26.1 mm, the thickness is 3.6 mm, the clear aperture is 21.5 mm, the curvature radius of the rear surface is 22.5 mm, the thickness is 15.116 mm, the clear aperture is 19.5 mm, the thickness of the aperture stop is 3.439 mm, the clear aperture is 7.921 mm, the thickness of the substrate between the filter film and the super lens is 3 mm, the clear aperture is 9.133 mm, the thickness of the binary surface 2 is 8.6 mm, and the clear aperture is 9.812 mm. The above parameters are only for this specific embodiment, but the optimization results are not limited to the above parameters.

[0031] Step 3: View the results such as the spot diagram, ray trace diagram, physical optics propagation, and encircled energy. The laser seeker obtains the position information of the target by analyzing and processing the energy distribution of the light spot on the four-quadrant detector. Since the optical system of the laser seeker is a non-imaging system, its performance evaluation mainly focuses on the size, roundness, stability, and uniformity of the energy distribution of the light spot, rather than the evaluation indexes of traditional imaging systems, and is mainly evaluated through the spot diagram, ray trace diagram, enclosed energy distribution diagram, etc. Figure 3Spot diagrams for different fields of view. A spot diagram shows the spot size diagram formed by the sampled light beam on a specified surface, which can reflect the spot size and energy of different fields of view. The spot radius sizes at 0°, 2.4°, 5.6°, 7°, 8°, and 9° fields of view are 2.44 mm, 2.50 mm, 2.54 mm, 2.55 mm, 2.56 mm, and 2.57 mm respectively. The spot shape is a uniform circle at different fields of view, and the light distribution is relatively uniform, meeting the design requirements of the four-quadrant detector for the spot size. Figure 4 For the ray trace diagrams of all fields of view. A ray trace diagram shows the landing coordinates of the light rays on a specified surface, mainly to show the position of the spots in different fields of view on the photosensitive surface of the detector, and the relative position between the spot and the detector center can be obtained intuitively. From Figure 4 It can be seen that at the 9° field of view, the spot covers the four quadrants of the detector and the edge does not exceed the detector edge. At the 18° field of view, the area of the spot on the photosensitive surface of the four-quadrant detector is greater than 50%, meeting the index requirements of the linear field of view ±9° and the full field of view ±18°. Figure 5 For the physical optical propagation energy distribution of all fields of view. Physical optics defines coherent light beams and conducts a comprehensive diffraction optical analysis of the system. Through the illuminance distribution of the spots in different fields of view, the relative distribution of energy can be qualitatively analyzed. After simulation, the position and energy distribution of the spots on the photosensitive surface at different fields of view are obtained. From Figure 5 It can be seen that the energy is the highest at the center position of the spots formed at each field of view, and the energy decreases sharply at the edge of the spots, forming an effective spot boundary. Figure 6 For the geometric encircled energy from 0° to 9° fields of view. Geometric encircled energy calculates the energy concentration using the intersection coordinates of geometric light rays and a surface, representing the distribution of energy with the spot radius. If the distribution is uniform, the relationship between the spot energy and the spot radius satisfies the formula: E = k × π × r 2 . In the formula, k is the energy per unit area. From Figure 6 It can be seen that the energy distribution of the spots in each market is uniform and consistent, and the energy and the spot radius are approximately in a parabolic relationship. The stability of the spot energy distribution within the 9° linear field of view is better than 1.88%, which can better meet the usage requirements of the system.

[0032] Step 4: After the above results all meet the various index requirements, extract the coefficients of the binary surface 2 to obtain the phase distribution formula of the metasurface, and calculate the specific phase values at different positions. Figure 7 For the phase distribution diagram of the metasurface lens.

[0033] Step 5: Construct a structure database. For the convenience of subsequent batch preparation of the structure, only the structure with a circular cross-section is selected in this scheme.

[0034] Step 6: Select the structure in the database constructed in Step 5 according to the required phase calculated in Step 4 to minimize the matching phase error. Figure 8 This is the phase matching result. The dots in the figure are the matched nanostructure units, and the lines are the required phase distributions of the metasurface lens. It can be seen from the results in the figure that good matching can be achieved at each position. Figure 9 This is a partial layout of the metasurface lens.

[0035] Step 7: Use the scalar diffraction algorithm to simulate the matched layout in MATLAB and view indicators such as the focal position, focusing efficiency, and transmittance.

[0036] Step 8: Input the matched metasurface into the ZEMAX system and view the results of the spot diagram, ray trace diagram, physical optics propagation energy distribution, and geometric encircled energy again.

[0037] Specific Embodiment 2 (the radome surface is aspherical):

[0038] Step 1: Build a model in ZEMAX, set the entrance pupil diameter to 16 mm, the central wavelength to 1064 nm, the field of view range to 0° - 16°, and the surface types from left to right are standard surface, standard surface, even aspherical surface, aperture standard surface, standard surface, binary surface 2, and image plane standard surface.

[0039] Here, the object side of the radome is convex, and the image side is concave. The object side is a standard surface, and the image side is an even aspherical surface; the metasurface lens has a positive focal power, its object side is a plane, and the image side is a diffractive surface, and the nanorod structures are arranged periodically. The light rays in different fields of view travel along the optical axis from the object side to the image side. First, they pass through the radome. The radome is a refractive lens with a negative focal power, which collects the light rays in different fields of view. The even aspherical surface increases the design freedom of the overall optical system and reduces the spherical aberration brought in the collimation and focusing systems. The radome changes the optical path by varying its own thickness perpendicular to the optical axis, that is, by controlling the transmission distance of the light rays in the radome to achieve the ideal phase distribution with different accumulated optical paths at different positions. Then the light rays pass through the aperture, which constrains the effective aperture of the light beam, controls the light throughput and the numerical aperture of the system, and limits the range and direction of the propagating light rays. After that, the light rays pass through the metasurface lens, and the wavefront is modulated through the phase mutation generated by the sub-wavelength structure at the interface to achieve focusing and reduce aberration, thereby improving the focusing effect and imaging quality of the light beam. The radome and the metasurface lens reasonably distribute the focal power and correct the aberration, achieving a good optical path folding. The combination of positive and negative focal powers can better control the spherical aberration, and the use of the metasurface element can correct and eliminate the high-order aberrations, giving full play to the advantages of the two elements and realizing the design of the minimalist laser seeker optical system.

[0040] Step 2: Set the optimization target of the focal length to 20 mm, the size of the metasurface to 15 mm, and the maximum incident angle on the filter film surface to 20° in the evaluation function editor, and optimize the entire system. Figure 10 This is the 2D layout diagram of the entire system after optimization. The optimized radius of curvature of the front surface of the fairing is 26 mm, the thickness is 2.376 mm, the clear aperture is 12.356 mm, the radius of curvature of the rear surface is 22 mm, the thickness is 13 mm, the clear aperture is 11.988 mm, the thickness of the aperture stop is 2.379 mm, the clear aperture is 8.499 mm, the thickness of the substrate between the filter film and the metalens is 3 mm, the clear aperture is 7.761 mm, the thickness of the binary surface 2 is 9.4 mm, and the clear aperture is 7.444 mm. The above parameters are only for this specific embodiment, but the optimization results are not limited to the above parameters.

[0041] Step 3: View the results such as the spot diagram, ray trace diagram, physical optics propagation, and encircled energy. The laser seeker obtains the position information of the target by analyzing and processing the energy distribution of the light spot on the quadrant detector. Since the optical system of the laser seeker is a non-imaging system, its performance evaluation mainly focuses on the size, roundness, stability, and uniformity of the energy distribution of the light spot, rather than the evaluation indicators of traditional imaging systems. It is mainly evaluated through the spot diagram, ray trace diagram, encircled energy distribution diagram, etc. Figure 11 This is the spot diagram for different fields of view. The spot diagram shows the spot size diagram formed by the sampled light beam on the specified surface, which can reflect the spot size and energy in different fields of view. The spot radii at the fields of view of (0°, 2.4°, 5.6°, 7°, 8°, 9°) are 2.42 mm, 2.49 mm, 2.60 mm, 2.66 mm, 2.71 mm, and 2.76 mm respectively. The spot shape is a uniform circle in different fields of view, and the light distribution is relatively uniform, meeting the design requirements of the quadrant detector for the spot size. Figure 12 This is the ray trace diagram for all fields of view. The ray trace diagram shows the landing coordinates of the light rays on the specified surface, mainly to show the position of the spots in different fields of view on the photosensitive surface of the detector, and the relative position between the spot and the center of the detector can be obtained intuitively. Figure 12 It can be seen that at the 9° field of view, the spot covers the four quadrants of the detector and the edge does not exceed the edge of the detector. The area of the spot at the 18° field of view on the photosensitive surface of the quadrant detector is greater than 50%, meeting the index requirements of the linear field of view ±9° and the full field of view ±18°. Figure 13 This is the physical optics propagation energy distribution for all fields of view. Physical optics defines coherent light beams and conducts a comprehensive diffractive optical analysis of the system. Through the illuminance distribution of the spots in different fields of view, the relative distribution of energy can be qualitatively analyzed. After simulation, the position and energy distribution of the spots on the photosensitive surface in different fields of view are obtained. Figure 13It can be seen that the spot formed under each field of view has the highest energy at the center position, and the energy sharply decreases at the edge of the spot, forming an effective spot boundary. Figure 14 is the geometric encircled energy for the 0-9° field of view. The geometric encircled energy is used to calculate the energy concentration using the intersection coordinates of geometric rays and the surface, representing the distribution of energy with respect to the spot radius. If the distribution is uniform, the relationship between the spot energy and the spot radius satisfies the formula: E = k × π × r 2 . In the formula, k is the energy per unit area. From Figure 14 it can be seen that the spot energy distributions in each market are uniform and consistent, and the energy and the spot radius are approximately in a parabolic relationship. The stability of the spot energy distribution within the 9° linear field of view is better than 0.72%, which can well meet the usage requirements of the system.

[0042] Step Four: After the above results all meet the requirements of each index, extract the coefficients of the binary surface 2 to obtain the phase distribution formula of the metasurface, and calculate the specific phase values at different positions. Figure 15 is the phase distribution diagram of the metasurface lens.

[0043] Step Five: Construct a structure database. For the convenience of subsequent batch preparation of structures, only structures with a circular cross-section are selected in this solution.

[0044] Step Six: Select structures from the database constructed in Step Five according to the required phase calculated in Step Four to minimize the matching phase error. Figure 16 is the phase matching result. The points in the figure are the matched nanostructure units, and the lines are the required phase distribution of the metasurface lens. From the results in the figure, it can be seen that good matching can be achieved at each position. Figure 17 is a partial layout of the metasurface lens.

[0045] Step Seven: Use the scalar diffraction algorithm to simulate the matched layout in MATLAB to view indicators such as the focal position, focusing efficiency, and transmittance.

[0046] Step Eight: Input the matched metasurface into the ZEMAX system, and view the results such as the spot diagram, ray trace diagram, physical optical propagation energy distribution, and geometric encircled energy again.

[0047] The above is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and all should be covered within the protection scope of the present invention.

Claims

1. A minimalist laser seeker optical system based on metasurface, characterized in that: It includes a fairing, an aperture and a meta-lens; the fairing is located at the side of the entire optical system, the fairing has a negative focal length, the aperture is located between the fairing and the meta-lens, both sides of the meta-lens are respectively coated with a filter film and an anti-reflection film, the filter film is located on the substrate on the side of the meta-lens without a nanostructure, the anti-reflection film is located on the side of the meta-lens with a nanostructure, and the meta-lens has a positive focal length; The light first passes through the fairing, which collects light from different fields of view; the collected light passes through the aperture, which constrains the effective aperture of the light, controls the amount of light passing and the numerical aperture of the system, and limits the range and direction of the propagation of light; finally, the light passes through the metalens, and the phase mutation generated by the nanostructure of the interface is used to control the wavefront, achieve focusing and reduce aberrations, thereby improving the focusing effect and imaging quality of the light beam.

2. According to claim 1, a minimalist laser seeker optical system based on a metasurface is characterized in that: The cross-sectional shape of the nanostructure is a centrosymmetric structure, including a circle and a square; or a non-centrosymmetric structure; the materials of the substrate and the nanostructure of the meta-lens are K9 glass and silicon, respectively.

3. A minimalist laser seeker optical system based on a metasurface according to claim 1, characterized in that: The surface of the fairing is spherical or aspherical, and the material is K9 glass, zinc sulfide or zinc selenide. The material of the filter film and the anti-reflection film is zinc sulfide or zinc selenide, or it is a film system formed by superimposing multiple materials.

4. A method for constructing a minimalist laser seeker optical system based on a metasurface as claimed in any one of claims 1 to 3, characterized in that: The following steps are involved: Step 1: Build a model in the ZEMAX simulation software and set some basic parameters, including entrance pupil diameter, field of view, wavelength, and material, perform ray tracing optimization design, and obtain the coefficients of the binary surface of the meta-lens; Meta-lenses can correct monochromatic aberrations and achieve focusing by controlling the wavefront of incident light, which gives them more freedom in optimizing the design. The design of apertures needs to consider many factors, including diffraction, aberration control, optical requirements, and application scenarios, and ensure that the design meets the requirements by optimizing the target. In the zemax simulation software, the aperture position is designed between the fairing and the meta-lens. The meta-lens uses a binary 2-surface, the maximum number of terms is set to 5, the normalized radius is 1, and the QPD photosensitive surface is on the far right. The meta-surface is realized by phase control through a phase function, and its phase function formula is: N is the number of polynomial coefficients, M is the diffraction order, A is i is the coefficient of ρ, and ρ is the normalized radial coordinate; by limiting the aperture of the meta-lens, the curvature, air spacing and other variable parameters of the optical system are optimized, and after optimization, the defocus amount is introduced to ensure the size of the final light spot; in the design process, the uniformity of the energy of the obtained light spot is ensured by controlling the size of the aberration. Since this optical system is a laser light source, only five monochromatic aberrations, namely spherical aberration, coma, astigmatism, field curvature and distortion, need to be corrected; Step 2: Meta-lens design: After optimizing the overall system, various parameters are obtained, that is, the phase distribution formula of the meta-lens is obtained; The design of meta-lens must first study the light field control mechanism of isotropic / anisotropic micro-nano structures, consider different structural design degrees of freedom, study the electromagnetic local resonance mechanism in isotropic, anisotropic, staggered units, and laminated structural units, and study the influence of different structural shapes and parameters on resonance and near-field and far-field scattered electric field distribution; then, through the equivalent medium and Jones matrix theory, study the phase control mechanism and law of the outgoing light field with different structures and parameters, and lay a theoretical foundation for the comprehensive control of the light field; provide a design scheme for large-area high-transmittance infrared meta-lenses; the phase control of the medium subwavelength structure includes resonant phase, geometric phase and propagation phase control; In the actual design process, by designing micro-nano structures with high degrees of freedom, the material properties, structural morphology, and geometric parameters of the structural unit are explored to the vector response of the light field, and the joint control of multiple parameters of the light wave is expected to be achieved; based on a limited database, the optical parameter control mechanism of the propagation phase in the equivalent waveguide is explored; according to the equivalent medium theory, the dielectric subwavelength structural unit is equivalent to a waveguide, and its propagation phase expression is: Among them, η eff is the equivalent refractive index of the nanostructure, which is determined by the refractive index of the material of the nanostructure itself and the equivalent waveguide mode of different structures, and h is the height of the nanostructure; the required phase is obtained by controlling the size of each sub-wavelength nanostructure unit; then the phase surface optimized in step 1 is used as the target phase for the design of the metasurface lens, and the structural matching of the metasurface lens is completed based on the micro-nanostructure phase database to complete the design of the metastructure lens; Step 3: Return the actual optical characteristics of the metalens to the minimalist optical system to evaluate and verify the actual system; use a scalar diffraction algorithm instead of a vector diffraction algorithm to simulate the light field of the system, or evaluate the actual wavefront error of the rear surface of the metalens phase plane of the minimalist optical system; make a relatively accurate analytical formula approximation of the actual phase when the metalens phase matching error is small, and substitute the analytical formula into the minimalist optical system for approximate ray tracing, so as to evaluate and verify the actual performance of the minimalist optical system.

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