Design method and design device of optical system, electronic equipment and storage medium

Abstract

The invention provides a design method for an optical system, and the method comprises the steps: initializing the structural parameters of the optical system according to the design demands, and enabling the optical system to comprise a superlens and a refractor; performing simulation processing based on the structure parameters to obtain an optical performance evaluation index of the optical system; based on the optical performance evaluation index, performing discrete optimization on a super lens parameter corresponding to the super lens in the structure parameters, and performing continuous optimization on a refraction lens parameter corresponding to the refraction lens in the structure parameters, so as to obtain a final structure parameter of which the optical performance evaluation index meets the target optical performance evaluation index; and obtaining the optical system meeting the design requirements based on the final structure parameters. According to the invention, discrete optimization is carried out on the parameters of the super lens in the optical system, and continuous optimization is carried out on the parameters of the refraction lens in the optical system, so that the optimization capability of the folding-super hybrid system is improved, and the performance of the optimized folding-super hybrid system is better.

Description

Technical Field

[0001] The present application relates to the technical field of optical systems, and in particular to a design method, a design device, an electronic device and a storage medium for an optical system. Background Art

[0002] Superlens is a specific application of metasurface, which modulates the amplitude, phase and polarization state of incident light through the nanostructures configured on it. With the development of superlens technology, the feasibility and applicability of optical systems composed of superlenses and traditional refractive lenses (also known as refractive-super hybrid systems) are becoming stronger and stronger.

[0003] However, the existing optical system design methods for optical systems composed of a combination of a metalens and a refractive lens usually only use one of continuous optimization or discrete optimization to simultaneously optimize the parameters corresponding to the refractive lens and the parameters corresponding to the metalens in the folded super-hybrid system. This is because the two optimization methods are difficult to effectively combine. Optimization using only one optimization method cannot effectively and accurately optimize all parameters in the folded super-hybrid system, resulting in poor optimization effect for optimizing the parameters in the folded super-hybrid system, resulting in the inability to further improve the performance of the optimized optical system, limiting the full release of the performance of the optical system. Summary of the invention

[0004] One purpose of the present application is to propose a design method for an optical system. The design method for an optical system provided in the present application effectively combines the two optimization methods by discretely optimizing the metalens parameters in the structural parameters corresponding to the optical system and continuously optimizing the refractive lens parameters in the structural parameters, so that the optical system has no error with the actual optical system during the optimization process through the optical performance evaluation index, thereby improving the optimization effect of the optical system and making the performance of the optimized optical system better.

[0005] According to one aspect of an embodiment of the present application, a design method of an optical system is disclosed, the design method comprising:

[0006] Initializing structural parameters of an optical system according to design requirements, wherein the optical system includes a metalens and a refractive lens;

[0007] Performing simulation processing based on the structural parameters to obtain an optical performance evaluation index of the optical system;

[0008] Based on the optical performance evaluation index, discretely optimizing the metalens parameters corresponding to the metalens in the structural parameters, and continuously optimizing the refractive lens parameters corresponding to the refractive lens in the structural parameters, so as to obtain the final structural parameters whose optical performance evaluation index meets the target optical performance evaluation index;

[0009] Based on the final structural parameters, an optical system that meets the design requirements is obtained.

[0010] In an exemplary embodiment of the present application, the simulation processing is performed based on the structural parameters to obtain the optical performance evaluation index of the optical system, including:

[0011] Based on the refractive lens parameters corresponding to the refractive lens in the structural parameters, performing light field propagation simulation processing or ray tracing simulation processing on the refractive lens;

[0012] Based on the superlens parameters corresponding to the superlens in the structural parameters, light field propagation simulation processing is performed on the superlens.

[0013] In an exemplary embodiment of the present application, the light field propagation simulation processing of the superlens is performed based on the superlens parameters corresponding to the superlens in the structural parameters, including:

[0014] If, in the structural parameters, the metalens phase in the metalens parameters is a continuous phase, the continuous phase is discretized to obtain discrete post-metalens parameters, and based on the discrete post-metalens parameters, the metalens is subjected to light field propagation simulation processing, wherein the metalens phase in the discrete post-metalens parameters is a discrete phase;

[0015] If, in the structural parameters, the metalens phase in the metalens parameters is a discrete phase, then based on the metalens parameters, light field propagation simulation processing is performed on the metalens.

[0016] In an exemplary embodiment of the present application, the discretization of the continuous phase to obtain the discrete post-metalens parameter includes:

[0017] Based on the metalens parameters in the structural parameters, a pre-established nanostructure database is traversed by a multi-parameter weighted difference minimum algorithm to obtain an initial nanostructure corresponding to each position on the metalens;

[0018] Based on the initial nanostructure, discrete post-superlens parameters corresponding to the superlens are obtained.

[0019] In an exemplary embodiment of the present application, based on the optical performance evaluation index, discretely optimizing the metalens parameters corresponding to the metalens in the structural parameters, and continuously optimizing the refractive lens parameters corresponding to the refractive lens in the structural parameters, comprises:

[0020] Based on the optical performance evaluation index, the metalens parameters are discretely optimized, and the refractive lens parameters are continuously optimized simultaneously.

[0021] In an exemplary embodiment of the present application, based on the optical performance evaluation index, discretely optimizing the metalens parameters corresponding to the metalens in the structural parameters, and continuously optimizing the refractive lens parameters corresponding to the refractive lens in the structural parameters, comprises:

[0022] Based on the optical performance evaluation index, the metalens parameters are discretely optimized, and the refractive lens parameters are asynchronously continuously optimized.

[0023] In an exemplary embodiment of the present application, based on the optical performance evaluation index, the metalens parameters corresponding to the metalens in the structural parameters are discretely optimized, and the refractive lens parameters corresponding to the refractive lens in the structural parameters are continuously optimized, and then further comprising:

[0024] Based on the optimized metalens parameters and the optimized refractive lens parameters, the optical performance evaluation index of the optimized optical system is obtained;

[0025] If the optical performance evaluation index of the optimized optical system meets the target optical performance evaluation index, the optimized metalens parameters and the optimized refractive lens parameters are output as final structural parameters;

[0026] If the optical performance evaluation index of the optimized optical system does not meet the target optical performance evaluation index, based on the optical performance evaluation index of the optimized optical system, the optimized metalens parameters are discretely optimized, and the optimized refractive lens parameters are continuously optimized until the optical performance evaluation index of the optimized optical system meets the target optical performance evaluation index.

[0027] According to one aspect of an embodiment of the present application, a design device for an optical system is disclosed, the design device comprising:

[0028] A determination module, used to initialize structural parameters of an optical system according to design requirements, wherein the optical system includes a metalens and a refractive lens;

[0029] A simulation module, used for performing simulation processing based on the structural parameters to obtain an optical performance evaluation index of the optical system;

[0030] An optimization module, for discretely optimizing the metalens parameters corresponding to the metalens in the structural parameters based on the optical performance evaluation index, and continuously optimizing the refractive lens parameters corresponding to the refractive lens in the structural parameters, so as to obtain final structural parameters whose optical performance evaluation index meets the target optical performance evaluation index;

[0031] An output module is used to obtain an optical system that meets the design requirements based on the final structural parameters.

[0032] According to one aspect of an embodiment of the present application, an electronic device is disclosed, comprising: one or more processing units; and a storage unit for storing one or more programs, wherein when the one or more programs are executed by the one or more processing units, the electronic device implements any one of the above embodiments.

[0033] According to one aspect of an embodiment of the present application, a computer-readable storage medium is disclosed, on which computer-readable instructions are stored. When the computer-readable instructions are executed by a processing unit of a computer, the computer is caused to execute any one of the above embodiments.

[0034] The design method of an optical system provided in an embodiment of the present application initializes the structural parameters of the optical system according to the design requirements, wherein the optical system includes a metalens and a refractive lens; performs simulation processing based on the structural parameters to obtain an optical performance evaluation index of the optical system; based on the optical performance evaluation index, discretely optimizes the metalens parameters corresponding to the metalens in the structural parameters, and continuously optimizes the refractive lens parameters corresponding to the refractive lens in the structural parameters, so as to obtain the final structural parameters whose optical performance evaluation index meets the target optical performance evaluation index; based on the final structural parameters, obtains an optical system that meets the design requirements. The design method of an optical system of the present application discretely optimizes the metalens parameters and continuously optimizes the refractive lens parameters. Since the metalens parameters are discrete variables and the refractive lens parameters are continuous variables, the design method provided in the present application can better optimize the metalens parameters and the refractive lens parameters, thereby improving the optimization effect of the structural parameters of the optical system, so that the performance of the optimized optical system is better.

[0035] Other features and advantages of the present application will become apparent from the following detailed description, or may be learned in part by the practice of the present application.

[0036] It should be understood that the foregoing general description and the following detailed description are exemplary only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The above and other objects, features and advantages of the present application will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings.

[0038] Figure 1 A flow chart of a method for designing an optical system provided in one embodiment of the present application is shown.

[0039] Figure 2 A light field simulation schematic diagram of the optical system provided in Example 1 of the present application is shown.

[0040] Figure 3The light intensity distribution diagram of the cross section along the yz direction of the fold-super mixing system before optimization provided in Example 1 of the present application is shown.

[0041] Figure 4 The light intensity distribution diagram of the cross section along the xy direction of the fold-super mixing system before optimization provided in Example 1 of the present application is shown.

[0042] Figure 5 A two-dimensional light field propagation diagram of the refractive-super hybrid system before optimization provided in Example 1 of the present application is shown.

[0043] Figure 6 The MTF diagram of the fold-hypermixing system before optimization provided in Example 1 of the present application is calculated by point spread function.

[0044] Figure 7 The light intensity distribution diagram of the optimized fold-super mixing system provided in Example 1 of the present application along the cross section in the yz direction is shown.

[0045] Figure 8 The light intensity distribution diagram of the optimized refractive-supermixing system provided in Example 1 of the present application along the xy direction cross section is shown.

[0046] Fig. 9 A two-dimensional light field propagation diagram of the optimized refractive-super hybrid system provided in Example 1 of the present application is shown.

[0047] Fig.10 The MTF diagram obtained by calculating the point spread function of the optimized fold-hyper mixing system provided in Example 1 of the present application is shown.

[0048] Fig.11 A schematic diagram of light field simulation of the optical system provided in Example 2 of the present application is shown.

[0049] Fig.12 The light intensity distribution diagram of the cross section along the yz direction of the fold-super mixing system before optimization provided in Example 2 of the present application is shown.

[0050] Fig.13 The light intensity distribution diagram of the cross section along the xy direction of the fold-super mixing system before optimization provided in Example 2 of the present application is shown.

[0051] Fig.14 A two-dimensional light field propagation diagram of the fold-super hybrid system before optimization provided in Example 2 of the present application is shown.

[0052] Fig.15 The MTF diagram of the fold-hypermixing system before optimization provided in Example 2 of the present application is calculated by point spread function.

[0053] Fig.16The light intensity distribution diagram of the optimized fold-super mixing system provided in Example 2 of the present application along the cross section in the yz direction is shown.

[0054] Fig.17 The light intensity distribution diagram of the optimized fold-super mixing system provided in Example 2 of the present application along the xy direction cross section is shown.

[0055] Fig.18 A two-dimensional light field propagation diagram of the optimized refractive-super hybrid system provided in Example 2 of the present application is shown.

[0056] Fig.19 The MTF diagram obtained by calculating the point spread function of the optimized fold-hyper mixing system provided in Example 2 of the present application is shown.

[0057] Fig. 20 A schematic diagram of a design device for an optical system provided in an embodiment of the present application is shown. DETAILED DESCRIPTION

[0058] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in a variety of forms and should not be construed as limited to the examples set forth herein; rather, these example embodiments are provided so that the description of the present application will be more comprehensive and complete and the concepts of the example embodiments will be fully conveyed to those skilled in the art. The accompanying drawings are only schematic illustrations of the present application and are not necessarily drawn to scale. The same reference numerals in the figures represent the same or similar parts, and thus their repeated description will be omitted.

[0059] In addition, the described features, structures or characteristics may be combined in one or more example embodiments in any suitable manner. In the following description, many specific details are provided to provide a full understanding of the example embodiments of the present application. However, those skilled in the art will appreciate that the technical solution of the present application may be practiced while omitting one or more of the specific details, or other methods, components, steps, etc. may be adopted. In other cases, known structures, methods, implementations or operations are not shown or described in detail to avoid obscuring the present application and making the various aspects of the present application obscure.

[0060] Some of the blocks shown in the accompanying drawings are functional entities that do not necessarily correspond to physically or logically independent entities. These functional entities can be implemented in software form, or in one or more hardware modules or integrated circuits, or in different networks and / or processing unit devices and / or microcontroller devices.

[0061] With the development of superlens technology, an optical system composed of a superlens and a refractive lens (also called a refractive-super hybrid system) has also been born. The refractive-super hybrid system can reduce the size of the optical system. This system design can reduce the size and weight of the system while maintaining high-performance imaging. This is especially important for applications that require compact optical systems, such as mobile phone cameras and small instruments. By using a refractive-super hybrid system, the performance can be guaranteed while achieving portability and lightweight of the equipment. However, in the existing design methods for the fold-hybrid system, after the initial structure of the fold-hybrid system is determined and optimized, usually only one of the continuous optimization or discrete optimization is used to optimize the parameters corresponding to the refractive lens and the metalens in the fold-hybrid system at the same time. This is because the two optimization methods are difficult to combine effectively. Continuous optimization and discrete optimization are two different types of optimization problem solving methods. Continuous optimization is used to find the optimal solution for the continuous variables in the problem, and discrete optimization is used to find the optimal solution for the discrete variables in the problem. The two optimization methods have different mathematical properties. Continuous optimization usually relies on the continuity and differentiability of the function and guides the optimization direction through gradient information, while discrete optimization is usually non-continuous and non-differentiable, and gradient information cannot be used directly. This makes it difficult for the two optimization methods to be combined and optimized in coordination under the same system evaluation function. Using only one optimization method to optimize all parameters in the fold-hybrid system often leads to poor optimization results, making it difficult for the optimized fold-hybrid system to perform at its best.

[0062] In order to overcome the above-mentioned defects in the related art, the present application provides a design method for an optical system. By discretely optimizing the metalens parameters in the structural parameters corresponding to the optical system and continuously optimizing the refractive lens parameters in the structural parameters, the two optimization methods are effectively combined, so that the optical system has no error with the actual optical system during the optimization process through the optical performance evaluation index, thereby improving the optimization effect of the optical system, and thus making the performance of the optimized optical system better.

[0063] Figure 1 A flow chart of a method for designing an optical system provided by an embodiment of the present application is shown as follows: Figure 1 As shown, the design method provided in this application includes:

[0064] Step S10: Initialize structural parameters of the optical system according to design requirements, wherein the optical system includes a metalens and a refractive lens.

[0065] Specifically, the optical system in the embodiment of the present application includes a refractive lens and a metalens. For ease of description, this optical system is collectively referred to as a refractive-super hybrid system. In the actual design process, it is first necessary to determine the structural parameters used to reflect the initial structure of the optical system according to the pre-set design requirements. It should be noted that the initial structure of the optical system refers to an optical structure in which both the metalens and the refractive lens have optical focal length and initially meet the design requirements, or are judged to meet the design requirements after subsequent optimization. The structural parameters include the metalens parameters corresponding to the metalens and the refractive lens parameters corresponding to the refractive lens. The design requirements for the refractive-super hybrid system include, but are not limited to, any one or more combinations of indicators such as modulation transfer function (MTF), total track length (TTL), working band, sensor size, field of view angle, working distance, focal length, aperture, principal ray angle, transmittance, and relative illumination.

[0066] Further, based on the working band and transmittance in the design requirements of the folding and super-hybrid system, the material parameters such as the material of the refractive lens, the substrate material of the metalens, and the nanostructured material of the metalens in the folding and super-hybrid system can be preliminarily selected. Subsequently, the number of lenses in the folding and super-hybrid system, the arrangement order of the lenses, and the type of lenses (spherical, aspherical or metalens) can be determined according to the optical parameters in the design requirements. Among them, the selection of the number of lenses should follow the principle of from few to many, that is, while meeting the design requirements, the number of lenses required for the folding and super-hybrid system should be minimized to reduce the complexity of the folding and super-hybrid system. However, it should be noted that since the present application provides a design method for a folding and super-hybrid system, there is at least one metalens and one refractive lens in the folding and super-hybrid system, that is, the design starts with one metalens and one refractive lens. If it is preliminarily determined that one metalens and one refractive lens cannot meet the design requirements, the number of metalens or refractive lenses is increased one by one until the folding and super-hybrid system obtained by the preliminary judgment can meet the design requirements after optimization.

[0067] Furthermore, after determining the material of the refractive lens in the fold-super hybrid system, the material corresponding to the metalens, the number of lenses, the arrangement order of the lenses, and the type of lenses, it is necessary to determine the structural parameters of the fold-super hybrid system, that is, the metalens parameters corresponding to the metalens and the refractive lens parameters corresponding to the refractive lens.

[0068] Among them, the superlens parameters include but are not limited to: phase, spatial gradient, group delay, group delay dispersion, equivalent refractive index; the refractive lens parameters include but are not limited to: radius of curvature, thickness, air spacing, K coefficient, high-order aspheric coefficient. It should be noted that the superlens parameters actually refer to the set of optical parameters corresponding to each nanostructure on the superlens. The optical parameters of the nanostructure can be obtained from a pre-established nanostructure database. That is to say, before the design method of the present application is started, it is necessary to establish a nanostructure database containing optical parameters corresponding to nanostructures of different wavelengths, including but not limited to the appearance shape of different nanostructures, the size of the corresponding appearance, nanocolumn height, nanocolumn radius, arrangement period, material, phase, group delay, group delay dispersion, and equivalent refractive index.

[0069] In one embodiment, determining the metalens parameters and the refractive lens parameters may be achieved by means of geometric optics calculations, wherein the geometric optics calculations include, but are not limited to: a power distribution equation, an achromatic equation, an athermal equation, and solving a PWC aberration equation.

[0070] In one embodiment, the determination of the metalens parameters and the refractive lens parameters can be achieved by ray tracing simulation processing. Ray tracing refers to describing the behavior changes of light after contacting an optical element by tracing the propagation trajectory of a representative light ray, thereby achieving the purpose of accurately describing the performance of the optical system.

[0071] In detail, when determining the superlens parameters and the refractive lens parameters through ray tracing simulation processing, a system evaluation function can be constructed, and the current optical performance evaluation index and the target optical performance evaluation index can be input into the system evaluation function. The value of the system evaluation function can be reduced through the optimization algorithm. The lower the value of the system evaluation function, the more the refractive-super hybrid system meets the design requirements. After multiple rounds of optimization, the superlens parameters and refractive lens parameters that meet the design requirements can be obtained.

[0072] In another embodiment, determining the metalens parameters and the refractive lens parameters can be achieved by simultaneously using geometric optics calculations and ray tracing simulation processing.

[0073] In the process of determining the parameters of the metalens and the refractive lens, in order to increase the speed of calculation, the spatial phase of the metalens in the refractive-super hybrid system satisfies:

[0074]

[0075]

[0076] Among them, (x, y) is the coordinate of the two-dimensional plane where the metalens is located, ω is the angular frequency of the incident light, c is the speed of the incident light, f is the focal length of the metalens, and r is the distance from any point on the metalens to the center of the metalens. For any initial phase, a i and b i is the phase coefficient, N is the phase order, and α is the spatial reference phase at the center of the superlens. It should be noted that

[0077] Step S20: Perform simulation processing based on the structural parameters to obtain optical performance evaluation indicators of the optical system.

[0078] Specifically, after determining the structural parameters of the refractive-super hybrid system, it is necessary to establish the refractive-super hybrid system according to the structural parameters, and simulate the refractive-super hybrid system to obtain the optical performance evaluation index corresponding to the refractive-super hybrid system. The optical performance evaluation index includes one or more of the image quality evaluation index, system back focus, Fno. (F number), system focal length, image height, working distance, maximum aperture, system total length, and field of view angle.

[0079] It should be noted that in the embodiments of the present application, the simulation processing includes ray tracing simulation processing and light field propagation simulation processing. Light field propagation simulation processing refers to the description of the propagation of light by means of Fourier optics and physical optics. For any known light field distribution of an object surface, the light field distribution of the light propagating from this object surface to any position in space can be calculated. The light field distribution of the object surface can be decomposed into a set of n point light sources under different field angles. The light field information of the object surface can be obtained according to the design requirements, where n can be defined according to the simulation accuracy requirements.

[0080] In one embodiment, simulation processing is performed based on the structural parameters to obtain optical performance rating indicators of the optical system, including:

[0081] Based on the refractive lens parameters corresponding to the refractive lens in the structural parameters, a light field propagation simulation process or a ray tracing simulation process is performed on the refractive lens;

[0082] Based on the superlens parameters corresponding to the superlens in the structural parameters, the light field propagation simulation of the superlens is performed.

[0083] Specifically, in the fold-super hybrid system, the fold-super hybrid system can be divided into a refractive lens part and a super lens part, the refractive lens part includes at least one refractive lens, the super lens part includes at least one super lens, and the fold-super hybrid system can include multiple refractive lens parts and multiple super lens parts. Therefore, the refractive lens part in the fold-super hybrid system is first constructed based on the refractive lens parameters corresponding to the refractive lens in the structural parameters, and then the super lens part in the fold-super hybrid system is constructed based on the super lens parameters corresponding to the super lens in the structural parameters. When the construction of the refractive lens part and the super lens part is completed, it means that the construction of the fold-super hybrid system with the structural parameters is completed; then the refractive lens part is subjected to light field propagation simulation processing or ray tracing simulation processing, and the super lens part is subjected to light field propagation simulation processing. When the simulation processing of all refractive lens parts and all super lens parts is completed, it means that the simulation processing of the fold-super hybrid system is completed, and the optical performance evaluation index of the fold-super hybrid system with the structural parameters can be obtained.

[0084] It should be noted that in the actual refractive-super hybrid system, the possible structure is refractive lens-super lens-refractive lens, such as Figure 2 As shown, Figure 2 The schematic diagram of light field simulation of the fold-super hybrid system provided by an embodiment of the present application is shown. The fold-super hybrid system includes two refractive lenses and one super lens. S2 and S3, S6 and S7 are the surfaces of the refractive lenses, and S4 and S5 are the surfaces of the super lens, wherein S4 is a super surface (a surface configured with a nanostructure), S5 is a base surface, and S8 is a virtual surface for light emission. Therefore, the fold-super hybrid system can be divided into two refractive lens parts and one super lens part. In the process of simulation processing, although the above steps put the simulation processing of the super lens part after the refractive lens part, in fact, the simulation processing process is performed on the entire fold-super hybrid system, which is continuous and sequentially performed along the direction of light path propagation. The above is only used as a functional description, which is intended to construct corresponding structures with corresponding parameters respectively and simulate the corresponding structures, and does not mean that the simulation processing of the super lens part must be completed after the simulation processing of the refractive lens part. Figure 2 The actual simulation process of the refractive-super hybrid system in is as follows: simulate the refractive lens part at the most upstream along the optical path, simulate the super lens part, and simulate the refractive lens part at the most downstream along the optical path. When the simulation process of the refractive lens part at the most downstream along the optical path is completed, it means that the simulation process of the entire refractive-super hybrid system is completed, and the optical performance evaluation index of the refractive-super hybrid system can be obtained. Similarly, the construction of the super lens part does not necessarily have to be after the construction of the refractive lens part, which can be done simultaneously.

[0085] In one embodiment, since the calculation speed of light field propagation is slow, considering the need for accelerated calculation, in this embodiment, during the simulation process, ray tracing simulation is performed on the refractive lens part, and light field propagation simulation is performed on the super lens part.

[0086] It should be noted that optical data conversion is required at the boundary between the ray tracing simulation and the light field propagation simulation, that is, when the light propagates from the ray tracing simulation area to the light field propagation simulation, the light data needs to be converted into light field data, and when the light propagates from the light field propagation simulation area to the ray tracing simulation area, the light field data needs to be converted into light data. Figure 2 In the fold-super hybrid system shown, the refracting lens part at the most upstream along the optical path is subjected to ray tracing simulation processing, the super lens part is subjected to light field propagation processing, and the refracting lens part at the most downstream along the optical path is subjected to ray tracing simulation processing. In this case, by providing different simulation processing modes for the refracting lens part and the super lens part respectively, the calculation rate of the simulation processing is effectively improved, thereby improving the design efficiency of the fold-super hybrid system.

[0087] In one embodiment, based on the superlens parameters corresponding to the superlens in the structural parameters, light field propagation simulation processing is performed on the superlens, including:

[0088] If, in the structural parameters, the metalens phase in the metalens parameters is a continuous phase, the continuous phase is discretized to obtain discrete metalens parameters, and based on the discrete metalens parameters, the light field propagation simulation is performed on the metalens, wherein the metalens phase in the discrete metalens parameters is a discrete phase;

[0089] If, in the structural parameters, the metalens phase in the metalens parameters is a discrete phase, then based on the metalens parameters, a light field propagation simulation process is performed on the metalens.

[0090] Specifically, unlike the ray tracing simulation process of geometric optics, the phase of the metalens in the light field propagation simulation process can be either a continuous phase or a discrete phase. When the phase of the metalens is a continuous phase, the phase of the metalens is expressed by the formula corresponding to the above-mentioned spatial phase; when the phase of the metalens is a discrete phase, the phase of the metalens is actually expressed by discrete phase points. Since the metalens is obtained by the periodic discrete arrangement of nanostructures in actual design and processing, there is an error between the phase of the metalens described by a continuous function and the actual phase of the metalens, while there is no error between the phase described by discrete phase points and the actual phase of the metalens.

[0091] Therefore, in this application, before constructing the superlens part according to the superlens parameters, the superlens phase in the superlens parameters will be judged. If the superlens phase is a discrete phase, the superlens part is directly constructed according to the superlens parameters corresponding to the superlens, and then the constructed superlens part is subjected to light field propagation simulation processing.

[0092] If the phase of the superlens is a continuous phase, it is necessary to discretize the continuous phase of the superlens at different wavelengths. After the discretization is completed, the discretized superlens parameters are obtained, and a new superlens part is constructed according to the discretized superlens parameters, and then the light field propagation simulation is performed on this superlens part.

[0093] Furthermore, the continuous phase is discretized to obtain the discretized metalens parameters, including:

[0094] Based on the superlens parameters in the structural parameters, a pre-established nanostructure database is traversed through a multi-parameter weighted difference minimum algorithm to obtain the initial nanostructure corresponding to each position on the superlens;

[0095] Based on the initial nanostructure, the discrete post-superlens parameters corresponding to the superlens are obtained.

[0096] Specifically, the multi-parameter weighted difference minimum algorithm is as follows:

[0097]

[0098] Where Dif(x,y) is the total discrete error at the two-dimensional plane (x,y) where the metalens is located, and q i is the wavelength λ i The weighting coefficient of is the wavelength λ of the nanostructure at the two-dimensional plane (x, y) where the superlens is located i The jth theoretical optical parameter under is the nanostructure in the nanostructure database at wavelength λ i It should be noted that the above theoretical optical parameters are the optical parameters of each nanostructure in the metalens parameters, and when calculating, one or more of the optical parameters of each nanostructure can be selected for calculation.

[0099] That is, first obtain the superlens parameters corresponding to the superlens in the structural parameters, which include the theoretical optical parameters corresponding to the nanostructure at each position on the superlens, and then traverse the nanostructure database through the above-mentioned multi-parameter weighted difference minimum algorithm, so that the nanostructure with the smallest total discrete error corresponding to the two-dimensional plane (x, y) where the superlens is located can be found. By analogy, the nanostructure database is traversed for each position on the superlens in the same way to obtain the initial nanostructure corresponding to each position on the superlens, where the initial nanostructure refers to the nanostructure with the smallest total discrete error corresponding to each position on the superlens. When the initial nanostructure corresponding to each position on the superlens is found, it means that the continuous phase discretization of the superlens is completed. In this case, the continuous phase of the superlens is discretized by using multiple optical parameters of each nanostructure on the superlens as indicators, which can more accurately realize the discretization of the continuous phase of the superlens, and the nanostructure obtained by the search has better optical performance, so that the error between the discretized superlens phase and the actual superlens phase is smaller, and the error of the light field propagation simulation processing is reduced.

[0100] It should be noted that when the discretization processing of the continuous phase of the superlens is completed, when the superlens part is subsequently constructed, the superlens part is constructed according to the optical parameters of the initial nanostructure obtained after the discretization processing, and after the new superlens part is constructed, the new superlens part is simulated.

[0101] In one embodiment, when the construction of the folded super hybrid system is completed and the subsequent simulation processing is performed, a light source needs to be input for subsequent simulation processing. Among them, the light source needs to be set to multiple wavelengths according to the working band in the design requirements, that is, the working band of the light source can be divided into n working wavelengths. For example, if the working band in the design requirements is 8μm-12μm, 41 working wavelengths can be set, namely 8μm, 8.1μm, 8.2μm, ..., 11.8μm, 11.9μm, 12μm, respectively. In the process of discretizing the continuous phase of the metalens, simulating the folded super hybrid system and subsequently discretely optimizing the parameters of the metalens, the 41 working wavelengths must be calculated accordingly.

[0102] In one embodiment, in the light field propagation simulation process, one or more of the Rayleigh-Sommerfeld diffraction formula, the Fresnel diffraction formula, and the Fraunhofer diffraction formula may be selected for simulation, or the angular spectrum corresponding to one or more of the Rayleigh-Sommerfeld diffraction formula, the Fresnel diffraction formula, and the Fraunhofer diffraction formula may be used for simulation.

[0103] Step S30: Based on the optical performance evaluation index, the metalens parameters corresponding to the metalens in the structural parameters are discretely optimized, and the refractive lens parameters corresponding to the refractive lens in the structural parameters are continuously optimized to obtain the final structural parameters whose optical performance evaluation index meets the target optical performance evaluation index.

[0104] Specifically, after obtaining the optical performance evaluation index of the fold-super hybrid system with structural parameters, the structural parameters of the fold-super hybrid system can be optimized based on the optical performance evaluation index. In the embodiment of the present application, considering that in the actual fold-super hybrid system, the refractive lens parameters corresponding to the refractive lens are continuous variables, and the super lens parameters corresponding to the super lens are discrete variables, in order to ensure that both the refractive lens parameters and the super lens parameters are accurately optimized, the present application continuously optimizes the refractive lens parameters and discretely optimizes the super lens parameters, and effectively combines the continuous optimization and the discrete optimization in the optimization process, thereby making the optimization effect of all parameters in the fold-super hybrid system better; Among them, it should be noted that in order to effectively combine the continuous optimization and the discrete optimization in the optimization process, the present application proposes a synchronous composite optimization method and an asynchronous composite optimization method.

[0105] In practical applications, the refractive lens parameters are continuously optimized, and the metalens parameters are discretely optimized, so as to obtain the structural parameters corresponding to the optimized fold-super hybrid system. The fold-super hybrid system is updated according to the structural parameters corresponding to the optimized fold-super hybrid system, and then the corresponding simulation processing is performed to obtain the optical performance evaluation indicators corresponding to the optimized fold-super hybrid system.

[0106] It should be noted that, during the optimization process, one or more of the parameters such as the radius of curvature, thickness, cone coefficient, air spacing, K coefficient, and higher-order aspheric coefficients of the refractive lens parameters are continuously optimized, and one or more of the parameters such as the phase, spatial gradient, group delay, group delay dispersion, and equivalent refractive index of the superlens parameters are discretely optimized.

[0107] In one embodiment, the optional discrete optimization algorithms include but are not limited to: simulated annealing algorithm, genetic algorithm, ant colony optimization algorithm, particle swarm optimization algorithm, artificial fish swarm algorithm, artificial bee colony algorithm, artificial neural network algorithm, taboo search algorithm, hill climbing method, and constructive heuristic algorithm.

[0108] The optional continuous optimization algorithms include but are not limited to: gradient descent optimization algorithm, damped least squares optimization algorithm, linear regularization algorithm, nonlinear regularization algorithm, unconstrained one-dimensional extreme value optimization algorithm, unconstrained multi-dimensional extreme value optimization algorithm, constrained optimization algorithm, quadratic regularization optimization algorithm, and multi-objective optimization algorithm.

[0109] In the embodiment of the present application, the objective functions of discrete optimization and continuous optimization are consistent. Therefore, before optimization, the objective function of optimization can be represented by constructing a system evaluation function using the optical performance evaluation index obtained by the above simulation processing steps, the target performance evaluation index obtained according to the design requirements, and the weight of each index, which is specifically represented as follows:

[0110]

[0111] Among them, MF 2 represents the objective function value, W i is the optimization weight of the i-th optical performance evaluation index, V i is the value of the i-th optical performance evaluation index of the current refractive-superhybrid system, T i is the i-th target performance evaluation index. It should be noted that W i 、V i and T i It is matched one by one, and during the optimization process, optimization can be performed according to one or more of the optical performance evaluation indicators.

[0112] Moreover, in the process of optimization, the present application proposes two methods: synchronous composite optimization and asynchronous composite optimization. The synchronous composite optimization is to discretely optimize the metalens parameters while continuously optimizing the refractive lens parameters; the asynchronous composite optimization is to discretely optimize the metalens parameters and continuously optimize the refractive lens parameters in a time-sharing manner.

[0113] In another embodiment, the refractive-hybrid system includes an aperture stop. If it is necessary to optimize the parameters corresponding to the aperture stop, discrete optimization can be performed using one or more of the size and position of the aperture stop as variables.

[0114] In one embodiment, based on the optical performance evaluation index, the metalens parameters corresponding to the metalens in the structural parameters are discretely optimized, and the refractive lens parameters corresponding to the refractive lens in the structural parameters are continuously optimized, including:

[0115] Based on the optical performance evaluation indicators, the metalens parameters are discretely optimized, and the refractive lens parameters are continuously optimized simultaneously.

[0116] In detail, for ease of explanation, the first optimized structural parameters are used to represent the optimized metalens parameters, and the second optimized structural parameters are used to represent the optimized refractive lens parameters. In this embodiment, a system evaluation function is first constructed based on the optical performance evaluation index; then, based on the system evaluation function, the metalens parameters are discretely optimized, and the refractive lens parameters are continuously optimized simultaneously, to obtain the first optimized structural parameters corresponding to the metalens and the second optimized structural parameters corresponding to the refractive lens.

[0117] Specifically, this embodiment optimizes the metalens parameters and the refractive lens parameters by synchronous composite optimization. First, the above-mentioned system evaluation function is constructed based on the optical performance evaluation index obtained by simulating the refractive-super hybrid system with structural parameters, and one or more of the optical performance evaluation indexes are selected for subsequent optimization steps. Then, based on the system evaluation function, one or more parameters in the metalens parameters are discretely optimized to obtain the first optimized structural parameters corresponding to the metalens; and at the same time, based on the system evaluation function, one or more parameters in the refractive lens parameters are continuously optimized to obtain the second optimized structural parameters corresponding to the refractive lens.

[0118] After the optimization is completed, the fold-super hybrid system is updated according to the first optimized structural parameters and the second optimized structural parameters to obtain an optimized fold-super hybrid system, and the optimized fold-super hybrid system is simulated to obtain an optical performance evaluation index corresponding to the optimized fold-super hybrid system. It should be noted that the steps of the simulation process are the same as above and will not be repeated here.

[0119] As an example, the gradient descent algorithm is selected as the continuous optimization algorithm, and the simulated annealing algorithm is selected as the discrete optimization algorithm. The gradient descent algorithm needs to calculate the gradient of each continuous variable with respect to the system evaluation function, and then refresh the continuous variable according to the gradient, and then use the new continuous variable to calculate the updated system evaluation function. This is considered as one round of optimization, and then the optimization is cyclically performed so that the continuous variable always changes in the direction that reduces the objective function value. The simulated annealing algorithm optimizes the discrete variables by randomly generating a Marcov chain, and then determines whether to accept the updated discrete variables and the objective function value through the Metropolis criterion. This is considered as one round of optimization, and then the optimization is cyclically performed so that the objective function value decreases.

[0120] In the process of synchronous composite optimization, it is assumed that all parameters of the refractive lens parameters and the metalens parameters are involved in the optimization. The synchronous composite optimization process is as follows:

[0121] S110, calculating the gradients of all parameters in the refractive lens parameters with respect to the system evaluation function;

[0122] S210, updating the parameters corresponding to each gradient respectively to obtain first optimized structural parameters corresponding to the refractive lens;

[0123] S310, randomly updating all parameters in the metalens parameters according to the Marcov chain, obtaining second optimized structural parameters corresponding to the metalens, and updating the objective function value according to the second optimized structural parameters;

[0124] S410, judging whether to accept the first optimized structural parameters and the second optimized structural parameters and the updated objective function value obtained by the optimization through the Metropolis criterion, and if so, outputting the first optimized structural parameters and the second optimized structural parameters; if not, returning to step S3, where the Marcov chain is randomly updated and judged.

[0125] It should be noted that S110-S210 are continuous optimizations, and S310 is discrete optimization, which are performed synchronously. Completing the above process from S110 to S410 is a round of synchronous composite optimization. In the case of such synchronous composite optimization, the real-time linkage optimization of the refractive lens part and the metalens part in the fold-super hybrid system can be achieved, thereby improving the optimization effect of the fold-super hybrid system and maximizing the performance of the fold-super hybrid system.

[0126] In another embodiment, based on the optical performance evaluation index, the metalens parameters corresponding to the metalens in the structural parameters are discretely optimized, and the refractive lens parameters corresponding to the refractive lens in the structural parameters are continuously optimized, including:

[0127] Based on the optical performance evaluation index, the metalens parameters are discretely optimized, and the refractive lens parameters are continuously optimized asynchronously.

[0128] In detail, in this embodiment, a system evaluation function is first constructed based on the optical performance evaluation index; then, based on the system evaluation function, the metalens parameters are discretely optimized to obtain the first optimized structural parameters corresponding to the metalens, and then the refractive lens parameters are asynchronously continuously optimized to obtain the second optimized structural parameters corresponding to the refractive lens; or, based on the system evaluation function, the refractive lens parameters are continuously optimized to obtain the second optimized structural parameters corresponding to the refractive lens, and then the metalens parameters are asynchronously discretely optimized to obtain the first optimized structural parameters corresponding to the metalens.

[0129] Specifically, since synchronous compound optimization has high requirements on the compatibility of different algorithms, and synchronous compound optimization will also increase the complexity of the program and reduce the speed of optimization operations, in view of various optimization requirements and goals, in this embodiment, the metalens parameters and the refractive lens parameters are optimized by asynchronous compound optimization. First, the above-mentioned system evaluation function is constructed based on the optical performance evaluation index obtained by simulating the refractive-super hybrid system with structural parameters, and one or more of the optical performance evaluation indexes are selected for subsequent optimization steps.

[0130] Based on the system evaluation function, one or more parameters in the metalens parameters are first discretely optimized for a first preset round to obtain the first optimized structural parameters corresponding to the metalens, and the fold-super hybrid system is updated based on the first optimized structural parameters to obtain the fold-super hybrid system that has been preliminarily optimized. In the process of discrete optimization, the refractive lens parameters are kept unchanged, that is, the structural parameters of the preliminarily optimized fold-super hybrid system are: the first optimized structural parameters and the refractive lens parameters. Then, the preliminarily optimized fold-super hybrid system is simulated to obtain the optical performance evaluation index corresponding to the preliminarily optimized fold-super hybrid system, and the system evaluation function is updated according to the optical performance evaluation index to obtain the preliminary system evaluation function corresponding to the preliminarily optimized fold-super hybrid system.

[0131] Based on the preliminary system evaluation function, one or more parameters of the refractive lens parameters are continuously optimized for a second preset round to obtain the second optimized structural parameters corresponding to the refractive lens, and then the preliminarily optimized fold-super hybrid system is updated according to the second optimized structural parameters to obtain the optimized fold-super hybrid system. In the process of continuous optimization, the first optimized structural parameters are kept unchanged, that is, the structural parameters of the optimized fold-super hybrid system are: the first optimized structural parameters and the second optimized structural parameters.

[0132] Finally, the optimized refractive-superhybrid system is simulated to obtain the optical performance evaluation index corresponding to the optimized refractive-superhybrid system.

[0133] It should be noted that the order of discrete optimization of the metalens parameters and continuous optimization of the refractive lens parameters can be interchanged arbitrarily; the first preset round and the second preset round are positive integers set according to actual optimization requirements, and may be equal or unequal.

[0134] Continuing with the above example of using the gradient descent algorithm as the continuous optimization algorithm and the simulated annealing algorithm as the discrete optimization algorithm, assuming that all parameters of the refractive lens parameters and the metalens parameters are involved in the optimization, the asynchronous composite optimization process is as follows:

[0135] S110', performing a first preset round of cyclic discrete optimization on all parameters in the metalens parameters by using a simulated annealing algorithm, and keeping the refractive lens parameters unchanged;

[0136] S210', updating the metalens parameters to the first optimized structural parameters obtained by cyclic discrete optimization, and updating the objective function value according to the first optimized structural parameters;

[0137] S310', performing a second preset round of cyclic continuous optimization on all parameters of the refractive lens parameters by using a gradient descent algorithm, and keeping the first optimized structural parameters unchanged;

[0138] S410', updating the refractive lens parameters to the second optimized structural parameters obtained by the cyclic continuous optimization, and updating the objective function value according to the second optimized structural parameters.

[0139] Note that the order of S110'-S210' and S310'-S410' can be replaced arbitrarily; the first preset round and the second preset round are positive integers set according to actual optimization requirements, and may be equal or unequal.

[0140] It should be noted that in the above examples of synchronous composite optimization process and asynchronous composite optimization process, all steps that require updating the objective function value require a simulation process of the current fold-hyper hybrid system.

[0141] Further, based on the optical performance evaluation index, the metalens parameters corresponding to the metalens in the structural parameters are discretely optimized, and the refractive lens parameters corresponding to the refractive lens in the structural parameters are continuously optimized, and then it also includes:

[0142] Based on the optimized metalens parameters and the optimized refractive lens parameters, the optical performance evaluation index of the optimized optical system is obtained;

[0143] If the optical performance evaluation index of the optimized optical system meets the target optical performance evaluation index, the optimized metalens parameters and the optimized refractive lens parameters are output as the final structural parameters;

[0144] If the optical performance evaluation index of the optimized optical system does not meet the target optical performance evaluation index, the optimized metalens parameters are discretely optimized based on the optical performance evaluation index of the optimized optical system, and the optimized refractive lens parameters are continuously optimized until the optical performance evaluation index of the optimized optical system meets the target optical performance evaluation index.

[0145] Specifically, for ease of explanation, the first optimized structural parameters are used to represent the optimized metalens parameters, and the second optimized structural parameters are used to represent the optimized refractive lens parameters. First, the target performance evaluation index of the fold-super hybrid system is obtained according to the design requirements of the fold-super hybrid system, and then the optical performance evaluation index corresponding to the optimized fold-super hybrid system is judged. If the optical performance evaluation index corresponding to the optimized fold-super hybrid system meets the target performance evaluation index, it is proved that the optimized fold-super hybrid system has met the design requirements, and the structural parameters of the optimized fold-super hybrid system are output as the final structural parameters, that is, the first optimized structural parameters and the second optimized structural parameters obtained by optimization are output as the final structural parameters at the same time.

[0146] If the optical performance evaluation index of the optimized fold-super hybrid system does not meet the target performance evaluation index, the first structural parameter is discretely optimized based on the optical performance evaluation index of the optimized fold-super hybrid system, and the second structural parameter is continuously optimized until the optical performance evaluation index of the optimized fold-super hybrid system meets the target performance evaluation index. In other words, if the optical performance of the optimized fold-super hybrid system does not meet the standard, the fold-super hybrid system will be cyclically optimized until the performance meets the standard. It should be noted that the process of re-optimization is to optimize again on the basis of the optimized fold-super hybrid system.

[0147] Continuing with the above synchronous composite optimization example, after step S410, the following steps are further included:

[0148] S510, perform simulation processing based on the first optimized structural parameters and the second optimized structural parameters to obtain the optical performance evaluation index corresponding to the optimized refractive-hybrid system, and determine whether the optical performance evaluation index meets the target performance evaluation index. If yes, output it; otherwise, update the system evaluation function based on the optical performance evaluation index, and jump back to step S110 to perform synchronous composite optimization again.

[0149] Continuing with the above asynchronous composite optimization example, after step S410', the following steps are further included:

[0150] S510', perform simulation processing based on the first optimized structural parameters and the second optimized structural parameters to obtain the optical performance evaluation index corresponding to the optimized refractive-hybrid system, and determine whether the optical performance evaluation index meets the target performance evaluation index. If yes, output it; otherwise, update the system evaluation function based on the optical performance evaluation index, and jump back to step S110' to perform asynchronous composite optimization again.

[0151] Step S40: Based on the final structural parameters, an optical system that meets the design requirements is obtained.

[0152] Specifically, when it is determined that the optical performance evaluation index of the optimized refractive-super hybrid system meets the target optical performance evaluation index and the final parameters are output, the structural parts can be designed according to the final structural parameters and the assembly drawing can be output. The refractive lens parameters corresponding to the refractive lens in the final structural parameters can be output as a processing drawing and traditional optical processing and production can be carried out. The super lens parameters corresponding to the super lens in the final structural parameters can be output as a layout and processing drawing for semiconductor process processing and production. Finally, the refractive-super hybrid system is assembled and debugged according to the assembly drawing to obtain a refractive-super system that meets the design requirements.

[0153] Example 1

[0154] In Example 1, the design requirements of the refractive-super hybrid system are: the object plane is infinite, the working band is 8-12μm, the focal length is 6.9mm, the F number is 1, the field of view is 30.76°, and the modulation transfer function must be greater than or equal to 0.3 at the cutoff frequency of 42lp / mm.

[0155] The optical parameters of the nanostructures in the nanostructure database corresponding to the working band are pre-established, including but not limited to: phase, group delay, group delay dispersion and equivalent refractive index.

[0156] According to the design requirements, the materials of the refractive lens, the base material of the superlens and the material of the nanostructure in the refractive-super hybrid system are all made of chalcogenide glass materials, and an architecture scheme of two refractive lenses and one superlens is adopted; then the structural parameters of the refractive-super hybrid system are obtained by means of geometric optics calculation, among which the curvature and thickness of the spherical refractive lens, the curvature, König coefficient, aspheric coefficient, thickness of the aspheric refractive lens, the superlens parameters corresponding to the superlens, the spacing between each lens, and the image plane distance are used as structural parameters, as well as variables for subsequent optimization.

[0157] Based on the structural parameters, optical modeling is performed, a refractive-hybrid system is constructed, and light field propagation simulation is performed, such as Figure 2 As shown, Figure 2 A schematic diagram of light field simulation of the optical system provided in Example 1 of the present application is shown, wherein the object plane and the image plane are omitted for ease of display; S2 and S3, S6 and S7 are surfaces of refractive lenses, S4 and S5 are surfaces of super lenses, wherein S4 is a super surface (a surface configured with a nanostructure), S5 is a base surface, and S8 is a virtual surface from which light is emitted.

[0158] Let the optical axis be z, the horizontal direction perpendicular to the optical axis be x, and the vertical direction perpendicular to the optical axis be y. Figure 3 The light intensity distribution diagram of the cross section along the yz direction of the fold-super mixing system before optimization provided in Example 1 of the present application is shown. Figure 4 The light intensity distribution diagram of the cross section along the xy direction of the refractive super mixing system before optimization provided in Example 1 of the present application is shown. Figure 3 and Figure 4 The cross section is selected based on the cross section including the point with the highest light intensity in the two-dimensional distribution; Figure 5 A two-dimensional light field propagation diagram of the refractive-super hybrid system before optimization provided in Example 1 of the present application is shown, wherein the color depth of each point represents the magnitude of the light intensity; Figure 6 The MTF diagram of the fold-hypermixing system before optimization provided in Example 1 of the present application is calculated by point spread function.

[0159] Subsequently, the fold-super hybrid system provided in Example 1 is simulated to obtain the optical performance evaluation index corresponding to the fold-super hybrid system. If the optical performance evaluation index does not meet the target performance evaluation index obtained according to the design requirements, the metalens parameters and the refractive lens parameters are cyclically asynchronously composite optimized until the optimized fold-super hybrid system meets the target performance evaluation index. The optimized results are shown in FIG. Figures 7 to 10 As shown, Figure 7 The light intensity distribution diagram of the optimized fold-super mixing system provided in Example 1 of the present application along the cross section in the yz direction is shown. Figure 8 The light intensity distribution diagram of the optimized fold-super mixing system provided in Example 1 of the present application along the xy direction section is shown, wherein: Figure 7 and Figure 8 The cross section is selected based on the cross section including the point with the highest light intensity in the two-dimensional distribution; Fig. 9 A two-dimensional light field propagation diagram of the optimized refractive-super hybrid system provided in Example 1 of the present application is shown, wherein the color depth of each point represents the magnitude of the light intensity; Fig.10 The MTF diagram obtained by calculating the point spread function of the optimized fold-hybrid system provided in Example 1 of the present application is shown. Figure 7 and Figure 8 It can be seen that after the asynchronous compound optimization of the fold-super hybrid system, the light intensity distribution of the fold-super hybrid system in the yz direction and in the xy direction becomes more concentrated, and the side lobe phenomenon is significantly reduced, which indicates that the chromatic aberration and aberration of the optimized fold-super hybrid system are improved; and from Fig.10 It can be seen that the MTF value of the optimized hybrid system is significantly improved and meets the design requirements.

[0160] Example 2

[0161] In Example 2, the design requirements of the refractive-super hybrid system are: the object plane is infinite, the working band is 8-12μm, the focal length is 6.9mm, the F number is 1, the field of view is 30.76°, and the modulation transfer function must be greater than or equal to 0.3 at the cutoff frequency of 42lp / mm.

[0162] The optical parameters of the nanostructures in the nanostructure database corresponding to the working band are pre-established, including but not limited to: phase, group delay, group delay dispersion and equivalent refractive index.

[0163] According to the design requirements, the material of the refractive lens, the base material of the superlens and the material of the nanostructure in the refractive-super hybrid system are all made of chalcogenide glass material, and an architecture scheme of two refractive lenses and one superlens is adopted; then the structural parameters of the refractive-super hybrid system are obtained by combining geometric optics calculation with ray tracing simulation processing, among which the curvature and thickness of the spherical refractive lens, the curvature, König coefficient, aspheric coefficient, thickness of the aspheric refractive lens, the superlens parameters corresponding to the superlens, the spacing between each lens, and the image plane distance are used as structural parameters, as well as variables for subsequent optimization.

[0164] Based on the structural parameters, optical modeling is performed, a refractive-hybrid system is constructed, and light field propagation simulation is performed, such as Fig.11 As shown, Fig.11 A schematic diagram of light field simulation of the optical system provided in Example 2 of the present application is shown, wherein the object plane and the image plane are omitted for ease of display; S2 and S3, S7 and S8 are surfaces of refracting lenses, S5 and S6 are surfaces of super lenses, wherein S5 is a super surface (a surface configured with a nanostructure), S6 is a base surface, S4 is an aperture surface of a refractive-super hybrid system, and S9 is a virtual surface for light emission.

[0165] Let the optical axis be z, the horizontal direction perpendicular to the optical axis be x, and the vertical direction perpendicular to the optical axis be y. Fig.12 The light intensity distribution diagram of the cross section along the yz direction of the fold-super mixing system before optimization provided in Example 2 of the present application is shown. Fig.13 The light intensity distribution diagram of the cross section along the xy direction of the fold-super mixing system before optimization provided in Example 2 of the present application is shown. Fig.12 and Fig.13 The cross section is selected based on the cross section including the point with the highest light intensity in the two-dimensional distribution; Fig.14 A two-dimensional light field propagation diagram of the refractive-super hybrid system before optimization provided in Example 2 of the present application is shown, wherein the color depth of each point represents the magnitude of the light intensity; Fig.15 The MTF diagram of the fold-hypermixing system before optimization provided in Example 2 of the present application is calculated by point spread function.

[0166] Subsequently, the fold-super hybrid system provided in Example 2 is simulated to obtain the optical performance evaluation index corresponding to the fold-super hybrid system. If the optical performance evaluation index does not meet the target performance evaluation index obtained according to the design requirements, the metalens parameters and the refractive lens parameters are cyclically and synchronously optimized until the optimized fold-super hybrid system meets the target performance evaluation index. The optimized result is shown in FIG. Figure 16 to Figure 17 As shown, Fig.16 The light intensity distribution diagram of the optimized fold-super mixing system along the yz direction section provided in Example 2 of the present application is shown. Fig.17The light intensity distribution diagram of the optimized fold-super mixing system provided in Example 2 of the present application along the xy direction section is shown, wherein: Fig.16 and Fig.17 The cross section is selected based on the cross section including the point with the highest light intensity in the two-dimensional distribution; Fig.18 A two-dimensional light field propagation diagram of the optimized refractive-super hybrid system provided in Example 2 of the present application is shown, wherein the color depth of each point represents the magnitude of the light intensity; Fig.19 The MTF diagram obtained by calculating the point spread function of the optimized fold-hybrid system provided in Example 2 of the present application is shown. Fig.16 and Fig.17 It can be seen that after the synchronous composite optimization of the fold-super hybrid system, the light intensity distribution of the fold-super hybrid system in the yz direction and the xy direction becomes more concentrated, and the side lobe phenomenon is significantly reduced, which indicates that the chromatic aberration and aberration of the optimized fold-super hybrid system are improved; and from Fig.19 It can be seen that the MTF value of the optimized hybrid system is significantly improved and meets the design requirements.

[0167] Furthermore, in a horizontal comparison between Example 1 and Example 2, Example 1 obtains the structural parameters only by means of geometric optics calculations, while Example 2 obtains the structural parameters by means of a combination of geometric optics calculations and ray tracing simulation processing; in Example 1, the structural parameters are optimized by means of asynchronous composite optimization, while in Example 2, the structural parameters are optimized by means of synchronous composite optimization; although Example 2 reduces the design speed by means of synchronous composite optimization, it improves the optimization effect of the fold-super hybrid system and maximizes the performance of the fold-super hybrid system.

[0168] The present application also provides a design device for an optical system, such as Fig. 20 As shown, Fig. 20 A schematic diagram of a design device for an optical system provided in an embodiment of the present application is shown, wherein the device includes:

[0169] A determination module 100 is used to initialize structural parameters of an optical system according to design requirements, wherein the optical system includes a metalens and a refractive lens;

[0170] A simulation module 200 is used to perform simulation processing based on structural parameters to obtain an optical performance evaluation index of the optical system;

[0171] An optimization module 300 is used to discretely optimize the metalens parameters corresponding to the metalens in the structural parameters based on the optical performance evaluation index, and continuously optimize the refractive lens parameters corresponding to the refractive lens in the structural parameters, so as to obtain the final structural parameters whose optical performance evaluation index meets the target optical performance evaluation index;

[0172] The output module 400 is used to obtain an optical system that meets the design requirements based on the final structural parameters.

[0173] The present application also provides an electronic device. The electronic device is in the form of a general-purpose computing device. The components of the electronic device may include, but are not limited to: at least one processing unit, at least one storage unit, and a bus connecting different system components (including the storage unit and the processing unit).

[0174] The storage unit stores program codes, which can be executed by the processing unit, so that the processing unit performs the steps of the exemplary embodiments described in the various exemplary embodiments above. For example, the processing unit can execute the following steps: Figure 1 The steps shown in .

[0175] The storage unit may include a readable medium in the form of a volatile memory unit, such as a random access memory unit (RAM) and / or a cache memory unit, and may further include a read-only memory unit (ROM).

[0176] The storage unit may also include a program / utility having a set (at least one) of program modules, such program modules including but not limited to: an operating system, one or more application programs, other program modules, and program data, each of which or some combination may include an implementation of a network environment.

[0177] The bus may represent one or more of several types of bus structures, including a memory unit bus or memory unit controller, a peripheral bus, an accelerated graphics port, a processing unit, or a local bus using any of a variety of bus architectures.

[0178] The present application also provides a computer-readable storage medium having computer-readable instructions stored thereon. When the computer-readable instructions are executed by a processing unit of a computer, the computer is enabled to execute a method provided by any of the above method embodiments.

[0179] Those skilled in the art will readily appreciate other embodiments of the present application after considering the specification and practicing the invention disclosed herein. The present application is intended to cover any modification, use or adaptation of the present application, which follows the general principles of the present application and includes common knowledge or customary techniques in the art that are not disclosed in the present application. The specification and examples are intended to be exemplary only, and the true scope and spirit of the present application are indicated by the appended claims.

Claims

1. A method for designing an optical system, characterized in that: The design method comprises: Initializing structural parameters of an optical system according to design requirements, wherein the optical system includes a metalens and a refractive lens; Performing simulation processing based on the structural parameters to obtain an optical performance evaluation index of the optical system; Based on the optical performance evaluation index, the metalens parameters corresponding to the metalens in the structural parameters are discretely optimized, and the refractive lens parameters corresponding to the refractive lens in the structural parameters are continuously optimized to obtain the final structural parameters whose optical performance evaluation index meets the target optical performance evaluation index; Based on the final structural parameters, an optical system that meets the design requirements is obtained.

2. The design method according to claim 1, characterized in that: The simulation process based on the structural parameters is performed to obtain an optical performance evaluation index of the optical system, including: Based on the refractive lens parameters corresponding to the refractive lens in the structural parameters, performing light field propagation simulation processing or ray tracing simulation processing on the refractive lens; Based on the superlens parameters corresponding to the superlens in the structural parameters, light field propagation simulation processing is performed on the superlens.

3. The design method according to claim 2, characterized in that: The step of performing light field propagation simulation processing on the superlens based on the superlens parameters corresponding to the superlens in the structural parameters includes: If, in the structural parameters, the metalens phase in the metalens parameters is a continuous phase, the continuous phase is discretized to obtain discrete post-metalens parameters, and based on the discrete post-metalens parameters, the metalens is subjected to light field propagation simulation processing, wherein the metalens phase in the discrete post-metalens parameters is a discrete phase; If, in the structural parameters, the metalens phase in the metalens parameters is a discrete phase, then based on the metalens parameters, light field propagation simulation processing is performed on the metalens.

4. The design method according to claim 3, characterized in that: The step of discretizing the continuous phase to obtain discrete metalens parameters includes: Based on the metalens parameters in the structural parameters, a pre-established nanostructure database is traversed by a multi-parameter weighted difference minimum algorithm to obtain an initial nanostructure corresponding to each position on the metalens; Based on the initial nanostructure, discrete post-superlens parameters corresponding to the superlens are obtained.

5. The design method according to claim 1, characterized in that: Based on the optical performance evaluation index, discretely optimizing the metalens parameters corresponding to the metalens in the structural parameters, and continuously optimizing the refractive lens parameters corresponding to the refractive lens in the structural parameters, comprises: Based on the optical performance evaluation index, the metalens parameters are discretely optimized, and the refractive lens parameters are continuously optimized simultaneously.

6. The design method according to claim 1, characterized in that: Based on the optical performance evaluation index, discretely optimizing the metalens parameters corresponding to the metalens in the structural parameters, and continuously optimizing the refractive lens parameters corresponding to the refractive lens in the structural parameters, comprises: Based on the optical performance evaluation index, the metalens parameters are discretely optimized, and the refractive lens parameters are asynchronously continuously optimized.

7. The design method according to claim 5 or 6, characterized in that: Based on the optical performance evaluation index, the metalens parameters corresponding to the metalens in the structural parameters are discretely optimized, and the refractive lens parameters corresponding to the refractive lens in the structural parameters are continuously optimized, and then the method further includes: Based on the optimized metalens parameters and the optimized refractive lens parameters, the optical performance evaluation index of the optimized optical system is obtained; If the optical performance evaluation index of the optimized optical system meets the target optical performance evaluation index, the optimized metalens parameters and the optimized refractive lens parameters are output as final structural parameters; If the optical performance evaluation index of the optimized optical system does not meet the target optical performance evaluation index, based on the optical performance evaluation index of the optimized optical system, the optimized metalens parameters are discretely optimized, and the optimized refractive lens parameters are continuously optimized until the optical performance evaluation index of the optimized optical system meets the target optical performance evaluation index.

8. A design device for an optical system, characterized in that: The design method according to any one of claims 1 to 7, wherein the design device comprises: A determination module, used to initialize structural parameters of an optical system according to design requirements, wherein the optical system includes a metalens and a refractive lens; A simulation module, used for performing simulation processing based on the structural parameters to obtain an optical performance evaluation index of the optical system; An optimization module, for discretely optimizing the metalens parameters corresponding to the metalens in the structural parameters based on the optical performance evaluation index, and continuously optimizing the refractive lens parameters corresponding to the refractive lens in the structural parameters, so as to obtain final structural parameters whose optical performance evaluation index meets the target optical performance evaluation index; An output module is used to obtain an optical system that meets the design requirements based on the final structural parameters.

9. An electronic device, characterized in that: include: one or more processing units; A storage unit, used to store one or more programs, when the one or more programs are executed by the one or more processing units, enables the electronic device to implement the method according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that: Computer-readable instructions are stored thereon, and when the computer-readable instructions are executed by a processing unit of a computer, the computer is caused to execute the method according to any one of claims 1 to 7.

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