Metasurface tolerance optimization method, electronic equipment and storage medium

Abstract

The invention discloses a tolerance optimization method of a metasurface, electronic equipment and a storage medium, and the method comprises the steps: determining a first feature size set of the metasurface; wherein the metasurface comprises a plurality of sub-wavelength units, and the first feature size set comprises a first feature size corresponding to each sub-wavelength unit in the plurality of sub-wavelength units; constructing a plurality of feature size sets according to the first feature size set and a preset tolerance range; calculating the diffraction efficiency of the metasurface of each feature size set on incident light waves; according to the first target diffraction efficiency and the diffraction efficiency of the metasurface of each feature size set on the incident light wave, constructing a target function; wherein the target function reflects the difference between the diffraction efficiency of each feature size set in the plurality of feature size sets and the first target diffraction efficiency; and performing size optimization on the first feature size set according to the target function to obtain and output a target feature size set.

Description

Technical Field

[0001] The present invention relates to the field of optical technology, and more specifically, to a metasurface tolerance optimization method, electronic device and storage medium. Background Art

[0002] Metasurface Optics Element (MOE) is an artificial two-dimensional or three-dimensional optical element with multiple subwavelength unit structures. During the MOE processing, the scale of the subwavelength unit structure deviates from the design scale due to processing errors. The sources of this deviation are divided into two types: one is the systematic deviation, that is, the scale of all subwavelength unit structures is generally larger or smaller, and the other is the random deviation, that is, the size and direction of the deviation of each metasurface product are different, and have a certain degree of randomness. The above two deviations may cause the actual production of MOE products to have different optical performance than expected, which in turn causes the MOE products to fail to meet the quality standards, thereby affecting the yield of MOE products. Summary of the invention

[0003] One purpose of an embodiment of the present invention is to provide a new technical solution for optimizing the tolerance of a metasurface.

[0004] According to a first aspect of the present invention, a method for optimizing tolerance of a metasurface is provided, comprising:

[0005] Determine a first characteristic size set of the metasurface; wherein the metasurface includes a plurality of sub-wavelength units, and the first characteristic size set includes a first characteristic size corresponding to each sub-wavelength unit in the plurality of sub-wavelength units;

[0006] Constructing a plurality of characteristic dimension sets according to the first characteristic dimension set and a preset tolerance range;

[0007] Calculating the diffraction efficiency of the metasurface of each characteristic size set for the incident light wave;

[0008] Constructing an objective function according to the first target diffraction efficiency and the diffraction efficiency of the metasurface of each characteristic size set to the incident light wave; wherein the objective function reflects the difference between the diffraction efficiency of each characteristic size set in the plurality of characteristic size sets and the first target diffraction efficiency;

[0009] According to the objective function, the first characteristic size set is optimized to obtain and output a target characteristic size set.

[0010] Optionally, performing size optimization on the first characteristic size set according to the objective function to obtain and output a target characteristic size set includes:

[0011] Optimizing the first characteristic size set according to the objective function;

[0012] When the number of size optimizations of the first characteristic size set is greater than or equal to a preset number threshold, the target characteristic size set is obtained and output.

[0013] Optionally, the optimizing the size of the first characteristic size set includes:

[0014] The first characteristic size set is optimized by using a gradient optimization algorithm.

[0015] Optionally, the preset tolerance range includes an upper limit value and a lower limit value, and the step of constructing a plurality of characteristic dimension sets according to the first characteristic dimension set and the preset tolerance range includes:

[0016] Determine a second characteristic dimension set according to the first characteristic dimension set and the lower limit value;

[0017] Determine a third characteristic dimension set according to the first characteristic dimension set and the upper limit value;

[0018] The first characteristic dimension set, the second characteristic dimension set and the third characteristic dimension set are used as a plurality of constructed characteristic dimension sets.

[0019] Optionally, determining a first characteristic size set of the metasurface includes:

[0020] Calculating a first light intensity distribution formed by the incident light wave passing through the metasurface with the initial phase distribution;

[0021] determining a fourth diffraction efficiency according to the first light intensity distribution and the target light intensity distribution;

[0022] According to the fourth diffraction efficiency, phase optimization is performed on the initial phase distribution to obtain a target phase distribution;

[0023] According to a preset mapping relationship and the target phase distribution, a first characteristic size set corresponding to the target phase distribution is determined; wherein the preset mapping relationship reflects a mapping relationship between the phase and the characteristic size of the sub-wavelength unit.

[0024] Optionally, optimizing the initial phase distribution according to the fourth diffraction efficiency to obtain a target phase distribution includes:

[0025] When the fourth diffraction efficiency is less than the second target diffraction efficiency, optimizing the initial phase distribution to obtain an optimized phase distribution;

[0026] According to the optimized phase distribution, updating the initial phase distribution, and recalculating the fourth diffraction efficiency;

[0027] When the fourth diffraction efficiency is greater than or equal to the second target diffraction efficiency, the target phase distribution is obtained.

[0028] Optionally, the subwavelength unit is a cylinder, and the first characteristic dimension set of the metasurface is a cylinder diameter set.

[0029] Optionally, after obtaining and outputting the target feature size set, the method further includes:

[0030] By deviating at least one of the coefficient of the objective function and the preset tolerance range, a condition combination set is constructed;

[0031] The target characteristic dimension set is used as a new first characteristic dimension set, and the target characteristic dimension set corresponding to each condition combination in the condition combination set is recalculated.

[0032] According to a second aspect of the present disclosure, an electronic device is provided, comprising a memory and a processor, wherein the memory is used to store executable instructions; and the processor is used to operate according to the control of the instructions to execute the method as described in the first aspect.

[0033] According to a third aspect of the present disclosure, a computer-readable storage medium is provided, on which computer-executable instructions are stored, characterized in that when the executable instructions are executed by a processor, the method described in the first aspect is implemented.

[0034] One beneficial effect of the present invention is to determine the first characteristic size set of the metasurface, construct multiple characteristic size sets according to the first characteristic size set and the preset tolerance range, calculate the diffraction efficiency of the metasurface of each characteristic size set to the incident light wave, construct an objective function according to the first target diffraction efficiency and the diffraction efficiency of the metasurface of each characteristic size set to the incident light wave, wherein the objective function reflects the difference between the diffraction efficiency and the first target diffraction efficiency, and optimize the size of the first characteristic size set according to the objective function to obtain and output the target characteristic size set. By incorporating the tolerance range into the design process of the target characteristic size set, the difference between the optical performance of the MOE product and the expectation caused by the system error and random error in the actual production process can be reduced, and the yield rate of the MOE product can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

[0036] Figure 1 is a schematic diagram of the hardware structure of an electronic device according to an embodiment of the present invention;

[0037] Figure 2 is a flow chart of a method for optimizing the tolerance of a hypersurface according to an embodiment of the present invention;

[0038] Figure 3 is a flow chart of calculating a first light intensity distribution according to an embodiment of the present invention;

[0039] Figure 4 is a flow chart of calculating a first light intensity distribution according to another embodiment of the present invention;

[0040] Figure 5 is a diagram of a mapping relationship between a phase and a cylinder radius according to an example of the present invention;

[0041] Figure 6 is a curve of the diffraction efficiency and the overall offset of the cylinder diameter set obtained after scanning the first diameter set according to an example of the present invention;

[0042] Figure 7 is a flow chart of a tolerance optimization method for a hypersurface composed of multiple cylinders according to an example of the present invention;

[0043] Figure 8 is a curve of diffraction efficiency and overall offset of cylinder diameter obtained after scanning the target diameter set according to an example of the present invention;

[0044] Fig. 9 is a diffraction efficiency variation curve of target diameter sets corresponding to 18 condition combinations according to an example of the present invention when displacement occurs;

[0045] FIG. 10( a ) is a diffraction efficiency curve of a target diameter set corresponding to a combination of conditions with a random error of ±10 nm after the target diameter set is offset according to an example of the present invention;

[0046] FIG. 10( b ) is a diffraction efficiency curve of a target diameter set corresponding to a condition combination of a random error of ±20 nm after a shift according to an example of the present invention;

[0047] Fig.11 is a schematic structural diagram of an electronic device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0048] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that the relative arrangement of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present invention unless otherwise specifically stated.

[0049] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.

[0050] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered as part of the specification.

[0051] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0052] It should be noted that like reference numerals and letters refer to similar items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0053] <Hardware Configuration>

[0054] Figure 1 is a block diagram of a hardware configuration of an electronic device 100 according to an embodiment of the present invention.

[0055] like Figure 1 As shown, the electronic device 100 may be a tablet computer, a desktop computer, a small computer, a workstation, a notebook computer, a mobile phone, etc., which is not limited here.

[0056] In this embodiment, refer to Figure 1 As shown, the electronic device 100 may include a processor 1100, a memory 1200, an interface device 1300, a communication device 1400, a display device 1500, an input device 1600, a speaker 1700, a microphone 1800, and the like.

[0057] The processor 1100 may be a mobile version processor. The memory 1200 may include, for example, a ROM (read-only memory), a RAM (random access memory), a non-volatile memory such as a hard disk, etc. The interface device 1300 may include, for example, a USB interface, a headphone interface, etc. The communication device 1400 may, for example, be capable of wired or wireless communication. The communication device 1400 may include a short-range communication device, for example, any device for short-range wireless communication based on short-range wireless communication protocols such as Hilink protocol, WiFi (IEEE 802.11 protocol), Mesh, Bluetooth, ZigBee, Thread, Z-Wave, NFC, UWB, LiFi, etc. The communication device 1400 may also include a remote communication device, for example, any device for WLAN, GPRS, 2G / 3G / 4G / 5G remote communication. The display device 1500 may be, for example, a liquid crystal display, a touch display, etc., and the display device 1500 is used to display the output target feature size. The input device 1600 may include, for example, a touch screen, a keyboard, etc. The user may input voice information through a microphone and output voice information through a speaker 1700.

[0058] In this embodiment, the memory 1200 of the electronic device is used to store instructions, and the instructions are used to control the processor 1100 to operate to at least perform the tolerance optimization method of the super surface implemented by the electronic device according to any embodiment of the present invention. The technician can design the instructions according to the scheme disclosed in the present invention. How the instructions control the processor to operate is well known in the art, so it will not be described in detail here.

[0059] Despite Figure 1 , multiple devices of the electronic device 100 are shown; however, the present invention may only involve some of the devices, for example, the electronic device 100 only involves the memory 1200 and the processor 1100 .

[0060] <Method Example>

[0061] Figure 2 1 is a flow chart of a method for optimizing the tolerance of a super surface according to an embodiment of the present invention, which method can be implemented by an electronic device 100.

[0062] according to Figure 2 As shown, the tolerance optimization method of the hypersurface of this embodiment may include the following steps S2100 to S2500:

[0063] Step S2100, determining a first characteristic dimension set of the metasurface.

[0064] In this embodiment, the metasurface is composed of a plurality of sub-wavelength units. The sub-wavelength unit may be a unit whose unit size is smaller than the wavelength of the incident light wave. By designing the shape, size and arrangement of the sub-wavelength units, the metasurface can modulate the propagation characteristics of the incident light wave, such as the amplitude, phase, polarization and wavefront.

[0065] The subwavelength unit can be a three-dimensional structure such as a cylinder, a sphere or a U-shaped groove.

[0066] Those skilled in the art should understand that the design of the subwavelength unit of the metasurface can be customized according to the required optical performance and application requirements, which is not limited here.

[0067] The first characteristic size set of the metasurface includes a first characteristic size corresponding to each sub-wavelength unit in a plurality of sub-wavelength units, wherein the characteristic size of a sub-wavelength unit may be a size in the sub-wavelength unit that affects the interaction between an incident light wave and the unit, and the first characteristic size of the sub-wavelength unit is an assigned value of the characteristic size of the sub-wavelength unit.

[0068] The first characteristic dimension set of the metasurface may be an initial value of a characteristic dimension preset for each sub-wavelength unit of the metasurface, or may be a characteristic dimension set obtained after phase optimization of an initial phase distribution of the metasurface, which is not limited here.

[0069] In some embodiments, the subwavelength unit is a cylinder, the characteristic size of the subwavelength unit is the cylinder diameter, the first characteristic size of the subwavelength unit is the first cylinder diameter, referred to as the first diameter, and correspondingly, the first characteristic size set is the first diameter set.

[0070] In some embodiments, the first characteristic dimension set may be a characteristic dimension set obtained after phase optimization of an initial phase distribution of the metasurface. Then, determining the first characteristic dimension set of the metasurface in step S2100 includes: steps S2100.1 to S2100.4.

[0071] Step S2100.1, calculating a first light intensity distribution formed by the incident light wave passing through the metasurface with an initial phase distribution.

[0072] In this embodiment, the phase distribution is a continuous phase, in which one phase represents the phase modulation of an incident light wave produced by a sub-wavelength unit, and the phase distribution may refer to the phase modulation of the incident light wave produced by multiple sub-wavelength units included in the metasurface. The initial phase distribution may be the initial modulation of the phase of the incident light wave by multiple sub-wavelength units of the metasurface.

[0073] The initial phase distribution of the metasurface can be determined by analyzing the target light intensity distribution of the current metasurface, where the target light intensity distribution of the current metasurface is the far-field light wave distribution that the designer currently hopes the metasurface will achieve.

[0074] For example, the far-field light wave distribution that the current designer hopes to achieve with the metasurface can be a focused light spot, a specific wavefront shaping, a specific beam shaping, etc. At this time, the far-field light wave distribution (i.e., the target light intensity distribution) can be theoretically analyzed to obtain the corresponding initial phase distribution.

[0075] After determining the initial phase distribution, the first light intensity distribution formed after the phase modulation of the incident light wave by the metasurface with the initial phase distribution can be calculated by simulation. The first light intensity distribution can be the far-field light effect distribution formed after the incident light wave passes through the metasurface.

[0076] In one example, the subwavelength unit is a cylinder, and the characteristic size of the subwavelength unit is the cylinder diameter. Usually, Figure 3 As shown, the process of calculating the first light intensity distribution through the initial phase distribution simulation can be: first, each phase in the scalar continuous phase (i.e., the initial phase distribution) is mapped to the corresponding cylinder diameter through a preset mapping relationship (i.e., the mapping relationship between the phase and the cylinder diameter), and a cylinder diameter set corresponding to the scalar continuous phase is obtained, and then the super surface structure is modeled by the cylinder diameter set, and then the modeled super surface is vector simulated (i.e., the modeled super surface structure is simulated using the principle of vector optics), and the obtained far-field light effect is the first light intensity distribution.

[0077] In another example, the subwavelength unit is a cylinder, and the characteristic size of the subwavelength unit is the cylinder diameter. If the designer wants the far-field light effect distribution or far-field light effect pattern to be achieved by the metasurface with a too small FOV (Field of View, i.e., the maximum field of view that the metasurface can cover), the coupling effect between the subwavelength unit structures of the metasurface is small, and the vector simulation result of the initial phase distribution is similar to the scalar simulation result. Figure 4 As shown, the scalar continuous phase of the initial phase distribution can be directly used to perform fast Fourier transform calculation to obtain the far-field light effect, which is the first light intensity distribution. Figure 4 The method shown does not require the simulation of the vector phase.

[0078] In some examples, when using the GS algorithm (Gerchberg Saxton algorithm) to perform phase optimization of a metasurface, the initial phase distribution can serve as the starting point of the phase optimization process.

[0079] Step S2100.2: determining a fourth diffraction efficiency according to the first light intensity distribution and the target light intensity distribution.

[0080] In this embodiment, the target light intensity distribution can be the far-field light effect distribution that the designer hopes the metasurface can achieve based on application requirements, which represents the optical effect that the metasurface design expects to achieve.

[0081] Exemplarily, the target light intensity distribution may be a focused light spot, a specific wavefront shaping, a specific beam shaping, or the like.

[0082] The fourth diffraction efficiency may refer to the proportion of the target light intensity distribution in the first light intensity distribution, which may be obtained by calculating the ratio between the light intensity (or light energy) belonging to the target light intensity distribution in the first light intensity distribution and the total light intensity (or total light energy) of the first light intensity distribution.

[0083] For the convenience of description, the light intensity (or light energy) in the first light intensity distribution that belongs to the target light intensity distribution is referred to as the target light intensity (or light energy).

[0084] Exemplarily, the total light energy of the first light intensity distribution can be expressed as I 总 , the target light intensity (or light energy) is I 目标 , then the fourth diffraction efficiency is: I 目标 / I 总 .

[0085] In the example of phase optimization by the GS algorithm, the fourth diffraction efficiency is used as an evaluation criterion to assess the degree of matching between the first light intensity distribution calculated by simulation and the target light intensity distribution.

[0086] The fourth diffraction efficiency can reflect the ability of the metasurface to guide the incident light wave to the target light intensity distribution. When the fourth diffraction efficiency is high, it means that more incident light waves can be concentrated in the target light intensity distribution, thereby improving the efficiency and performance of the optical system.

[0087] Step S2100.3, performing phase optimization on the initial phase distribution according to the fourth diffraction efficiency to obtain a target phase distribution.

[0088] In this embodiment, the initial phase distribution can be phase optimized according to the fourth diffraction efficiency to change the diffraction characteristics of the incident light wave so that the proportion of the target light intensity distribution in the first light intensity distribution increases, that is, the goal of the phase optimization is to improve the fourth diffraction efficiency.

[0089] In some embodiments, in step S2100.3, the initial phase distribution is phase optimized to obtain a target phase distribution, including: the initial phase distribution is phase optimized by a phase recovery algorithm to obtain a target phase distribution.

[0090] In this embodiment, the phase recovery algorithm may be, for example, a GS algorithm, a Fourier transform algorithm, a phase shift method, an iterative Fourier transform algorithm, etc., which is not limited here.

[0091] In the process of phase optimization by the phase recovery algorithm, the second target diffraction efficiency can be set as the optimization target for the initial phase optimization, that is, when the fourth diffraction efficiency obtained by simulation calculation is greater than or equal to the second target diffraction efficiency, the phase optimization is terminated and the target phase distribution is output. A number threshold can also be set as the optimization target for the initial phase optimization, that is, when the number of phase optimization is greater than or equal to the number threshold, the phase optimization is terminated and the target phase distribution is output, which is not limited here.

[0092] Those skilled in the art should understand that the specific method of performing phase optimization through a phase recovery algorithm is well known in the art and will not be elaborated here.

[0093] In some embodiments, in step S2100.3, the initial phase distribution is optimized according to the fourth diffraction efficiency to obtain a target phase distribution, including: steps SA1 to SA3.

[0094] Step SA1, when the fourth diffraction efficiency is less than the second target diffraction efficiency, optimizing the initial phase distribution to obtain an optimized phase distribution.

[0095] In this embodiment, the second target diffraction efficiency is an optimization target of the fourth diffraction efficiency set for phase optimization, so as to determine whether to continue phase optimization.

[0096] When the fourth diffraction efficiency is less than the second target diffraction efficiency, it means that the proportion of the target light intensity distribution in the current first light intensity distribution has not reached the target value. At this time, it is necessary to perform phase optimization on the initial phase distribution to obtain the optimized phase distribution.

[0097] Step SA2: updating the initial phase distribution according to the optimized phase distribution, and recalculating the fourth diffraction efficiency.

[0098] In this embodiment, the optimized phase distribution is used as the updated initial phase distribution, and the updated first light intensity distribution is calculated based on the updated initial phase distribution. Then, the fourth diffraction efficiency is re-determined based on the proportion of the target light intensity distribution in the updated first light intensity distribution.

[0099] Step SA3: obtaining the target phase distribution when the fourth diffraction efficiency is greater than or equal to the second target diffraction efficiency.

[0100] In this embodiment, the above steps SA1 to SA3 are repeatedly performed until the recalculated fourth diffraction efficiency is greater than or equal to the second target diffraction efficiency. When the recalculated fourth diffraction efficiency is greater than or equal to the second target diffraction efficiency, it means that the proportion of the target light intensity distribution in the updated first light intensity distribution meets the target value, the phase optimization is terminated, and the optimized phase distribution is used as the target phase distribution.

[0101] Step S2100.4, determining a first characteristic size set corresponding to the target phase distribution according to a preset mapping relationship and the target phase distribution.

[0102] In this embodiment, the target phase distribution is a continuous phase. The preset mapping relationship reflects the mapping relationship between the phase and the characteristic size of the sub-wavelength unit, that is, one phase corresponds to one characteristic size.

[0103] After the target phase distribution of the continuous phase is obtained, the first characteristic size corresponding to each phase in the continuous phase can be obtained according to the preset mapping relationship, and then the first characteristic size set corresponding to the target phase distribution can be obtained.

[0104] In one example, the subwavelength unit is a cylinder, the characteristic size is the cylinder diameter, and the preset mapping relationship reflects the mapping relationship between the phase and the cylinder radius. The mapping relationship is as follows: Figure 5 As shown by the dotted line, it can be seen that there is a nonlinear relationship between the cylinder radius and the phase. Figure 5 The solid line shown represents the relationship between the cylinder radius and the transmittance. After obtaining the target phase distribution, the Figure 5 The preset mapping relationship shown converts each phase in the target phase distribution into a corresponding first diameter, thereby obtaining a first diameter set (ie, a first characteristic size set) corresponding to the target phase distribution.

[0105] After obtaining the first diameter set of the metasurface, the inventors adjusted the first diameter set as a whole, and then reversely mapped it back to the scalar continuous phase according to the preset mapping relationship, and obtained the far-field light effect after Fourier transform (FFT). The diffraction efficiency obtained by the far-field light effect was used as the evaluation function, and the following was obtained: Figure 6 The corresponding curve of the diffraction efficiency and the overall offset of the cylindrical diameter set obtained after scanning the first diameter set is shown. Figure 6It can be known that, when the first diameter set is used as the reference cylinder diameter set in the actual production process, if the cylinder diameter in the actual production process has a large deviation (i.e., a large error) from the first diameter in the first diameter set, its diffraction efficiency will be greatly lost. In other words, if the first diameter set is directly used as the reference cylinder diameter set for actual production without fully considering the error in the processing process, the optical performance of the actually produced MOE product will be different from the expected one, thus affecting the product yield.

[0106] In this regard, the embodiment of the present application optimizes the size of each characteristic dimension in the first characteristic dimension set by adding a preset tolerance range in the design stage of the MOE product through the following steps S2200 to S2500, so as to avoid the problem that the optical performance of the actually produced MOE products is different from the expected one due to failure to consider the errors in the processing process, thereby improving the yield of the MOE products.

[0107] Step S2200: construct multiple feature size sets according to the first feature size set and a preset tolerance range.

[0108] In this embodiment, the preset tolerance range may be a range of allowable system errors preset when designing the metasurface, which indicates the maximum system error that may occur in the actual manufacturing process when designing the metasurface.

[0109] The preset tolerance range is a design parameter that can be optimized and adjusted during the design phase. It is different from the processing error, which is the difference between the actual size value and the theoretical size value produced during the manufacturing process.

[0110] The preset tolerance range can be, for example, 0 to 5 nm, or ±10 nm, etc. Those skilled in the art should understand that the preset tolerance range can be set according to the processing conditions for the metasurface in the actual production process. For example, when the processing conditions are good, the system error is small, and a smaller tolerance range can be set; when the processing conditions are poor, the system error is large, and a larger tolerance range can be set. The specific size of the tolerance range is not limited here.

[0111] The plurality of feature size sets include at least a first feature size set.

[0112] In one example, the constructed plurality of feature size sets include a first feature size set, a second feature size set, and a third feature size set.

[0113] In some embodiments, the preset tolerance range includes an upper limit value and a lower limit value.

[0114] For an example in which the preset tolerance range is 0 to 5 nm, the upper limit value is 5 nm and the lower limit value is 0 nm.

[0115] For an example in which the preset tolerance range is -30 nm to 30 nm, the upper limit value is 30 nm and the lower limit value is -30 nm.

[0116] In these embodiments, in step S2200, multiple feature size sets are constructed according to the first feature size set and the preset tolerance range, including: step S2200.1 to step S2200.3.

[0117] Step S2200.1: Determine a second characteristic dimension set according to the first characteristic dimension set and the lower limit value.

[0118] In this embodiment, a lower limit value is added to each first characteristic dimension in the first characteristic dimension set to obtain a second characteristic dimension set.

[0119] Step S2200.2: Determine a third characteristic dimension set according to the first characteristic dimension set and the upper limit value.

[0120] In this embodiment, an upper limit value is added to each first characteristic dimension in the first characteristic dimension set to obtain a third characteristic dimension set.

[0121] Step S2200.3: taking the first characteristic dimension set, the second characteristic dimension set and the third characteristic dimension set as the constructed multiple characteristic dimension sets.

[0122] Exemplarily, the first characteristic size set is 40nm, 50nm, 60nm..., the lower limit is -30nm, and the upper limit is 30nm; the second characteristic size set is 10nm, 20nm, 30nm..., and the third characteristic size set is 70nm, 80nm, 90nm...

[0123] Step S2300, calculating the diffraction efficiency of the metasurface of each characteristic size set to the incident light wave.

[0124] In this embodiment, the diffraction efficiency corresponding to the metasurface of the first characteristic size set is the first diffraction efficiency, the diffraction efficiency corresponding to the metasurface of the second characteristic size set is the second diffraction efficiency, and the diffraction efficiency corresponding to the metasurface of the third characteristic size set is the third diffraction efficiency.

[0125] The calculation of the first diffraction efficiency, the second diffraction efficiency and the third diffraction efficiency is basically the same as the calculation method of the fourth diffraction efficiency mentioned above. The difference is that the calculation of the first diffraction efficiency, the second diffraction efficiency and the third diffraction efficiency requires first obtaining the corresponding continuous phase through the characteristic size set, and then calculating the diffraction efficiency.

[0126] Step S2400, constructing an objective function according to the first target diffraction efficiency and the diffraction efficiency of the metasurface of each characteristic size set to the incident light wave.

[0127] In this embodiment, the first target diffraction efficiency is an optimization target set for size optimization, which is used to determine whether to continue size optimization. The objective function reflects the difference between the diffraction efficiency of each characteristic size set in the multiple characteristic size sets and the first target diffraction efficiency.

[0128] For example, the objective function may be the following formula (1):

[0129]

[0130] in, is the first target diffraction efficiency, eff1 is the second diffraction efficiency corresponding to the second characteristic size set, eff2 is the first diffraction efficiency corresponding to the first characteristic size set, eff3 is the third diffraction efficiency corresponding to the third characteristic size set, and 0.95 is the coefficient of the objective function.

[0131] Step S2500: Optimize the first characteristic size set according to the objective function to obtain and output a target characteristic size set.

[0132] In this embodiment, the first characteristic dimension in the first characteristic dimension set is adjusted to minimize the objective function. When the objective function value is less than or equal to a preset value, or when the number of dimension optimization times is greater than or equal to a preset threshold, the dimension optimization is terminated to obtain and output the target characteristic dimension.

[0133] In some embodiments, in step S2500, the first characteristic size set is optimized according to the objective function to obtain and output a target characteristic size set, including: step S2500.1 to step S2500.2.

[0134] Step S2500.1, optimizing the first characteristic dimension set according to the objective function.

[0135] In this embodiment, the objective function is reduced by adjusting the first characteristic size in the first characteristic size set.

[0136] Step S2500.2: when the number of size optimizations of the first characteristic size is greater than or equal to a preset number threshold, obtain and output a target characteristic size set.

[0137] In this embodiment, the preset number threshold may be, for example, 600 times, or may be other number thresholds, which are not limited here.

[0138] When the number of size optimizations is greater than or equal to a preset number threshold, the size optimization of the first characteristic size set is terminated, and a target characteristic size set is output.

[0139] For ease of description, the number threshold set for size optimization is called the first number threshold, and the number threshold set for phase optimization is called the second number threshold. The first number threshold and the second number threshold can be the same or different, and are not limited here.

[0140] In some embodiments, in order to improve the effect of size optimization, the first number threshold is greater than the second number threshold.

[0141] In some embodiments, optimizing the first characteristic size set in step S2500 or step S2500.1 includes:

[0142] The first characteristic size set is optimized by a gradient optimization algorithm.

[0143] In this embodiment, a mapping relationship between diffraction efficiency and continuous phase is constructed by inverse Fourier transform, and a mapping relationship between phase and characteristic size is constructed.

[0144] For example, the subwavelength unit is a cylinder, and the characteristic size is the cylinder diameter. A 9th-order polynomial fitting method can be used to fit the subwavelength unit. Figure 5 The mapping relationship curve between the cylinder radius and the phase shown in FIG. 2 is fitted to obtain the corresponding relationship between the cylinder diameter D and the phase as shown in formula (2).

[0145]

[0146] in, is the phase, D is the cylinder diameter, and a, a1, a2…a9 are coefficients.

[0147] Those skilled in the art should understand that the method of constructing the mapping relationship between diffraction efficiency and continuous phase through inverse Fourier transform is well known and will not be elaborated here.

[0148] In the process of optimizing the size of the first characteristic size set, the rate of change of the diffraction efficiency (i.e., the gradient) when the continuous phase changes is determined according to the mapping relationship between the diffraction efficiency and the continuous phase, and then the direction of change of the continuous phase corresponding to the direction of increase in the diffraction efficiency (i.e., the direction in which the objective function decreases) is determined. Then, according to the mapping relationship between the phase and the characteristic size, the rate of change of the phase when the characteristic size changes (i.e., the gradient) is determined. For example, the gradient of the phase relative to the cylinder diameter can be determined by taking the partial derivative of the above formula (2). Then, according to the direction of change of the continuous phase and the rate of change of the phase when the characteristic size changes, the direction of change of the characteristic size is determined. Finally, according to the preset step size and the direction of change of the characteristic size, the optimized characteristic size is determined.

[0149] According to an embodiment of the present application, the gradient information can be effectively used to guide the update process of the first feature size in the first feature size set through the gradient optimization algorithm, so that the objective function can be reduced faster than randomly searching the first feature size set, thereby reducing the computational complexity of size optimization.

[0150] The target feature size set is the feature size set after size optimization.

[0151] For example, Figure 7 As shown, the process of diameter optimization for the first diameter set of the cylinder is shown, wherein the cylinder diameter D is the first diameter set (i.e., the first characteristic size set), the preset tolerance range is ±30nm, D-30nm is the second characteristic size set, and D+30nm is the third characteristic size set. For the first characteristic size set, the second characteristic size set, and the third characteristic size set, the corresponding continuous phase distributions are obtained, namely phase2, phase1, and phase3 in the figure. The first diffraction efficiency corresponding to the first characteristic size set is eff2, the second diffraction efficiency corresponding to the second characteristic size set is eff1, and the third diffraction efficiency corresponding to the third characteristic size set is eff3. The objective function is the loss function loss. The size of the first diameter set D is optimized by the gradient descent algorithm. When the number of size optimizations of the first characteristic size set is greater than 600, the size optimization is terminated, and the target diameter set D', i.e., the target characteristic size set, is output.

[0152] Continuing with the above example, after obtaining the target diameter set, the diffraction efficiency of the target diameter set after the offset can be calculated to obtain Figure 8 The overall offset curve of diffraction efficiency and cylinder diameter set obtained by scanning the target diameter is shown. Figure 8 The change ratio of diffraction efficiency when the target diameter set shifts Figure 6 The diffraction efficiency changes slowly when the first diameter set is offset, and its diffraction efficiency is relatively stable, and can still reach 70% diffraction efficiency within the tolerance range. Therefore, by using the target diameter set (i.e., the target characteristic size set) as the reference size set in the actual production process, compared with using the first diameter set (i.e., the first characteristic size set) as the reference size set in the actual production process, the problem of a significant decrease in diffraction efficiency due to the offset of the actual production size of the product can be avoided, and the stability of the optical performance of the metasurface of the target characteristic size set is improved.

[0153] In some embodiments, after executing step S2500 to obtain and output the target feature size set, the method further includes: step S4100 and step S4200.

[0154] Step S4100, constructing a condition combination set by deviating at least one of the coefficient of the objective function and the preset tolerance range.

[0155] Since the preset tolerance range corresponds to the system error in the actual production process, and does not take into account the random error in the actual production process, this application is designed to take into account the situation of random error, as follows:

[0156] After the target characteristic size set is obtained through step S2500, a condition combination set consisting of multiple condition combinations is obtained by conditional deviation, that is, by deviation of the coefficient of the target function and / or the preset tolerance range. The coefficient of the target function is 0.95 in the above formula (1), and the coefficient can be adjusted to, for example, 0.90.

[0157] Exemplarily, the coefficient of the objective function for condition combination 1 is 0.85, and the preset tolerance range is ±10 nm; the coefficient of the objective function for condition combination 2 is 0.90, and the preset tolerance range is ±20 nm.

[0158] Step S4200: taking the target characteristic dimension set as a new first characteristic dimension set, and recalculating the target characteristic dimension set corresponding to each condition combination in the condition combination set.

[0159] In this embodiment, for each condition combination, the target feature dimension set is used as the first feature dimension set in step S2100, and steps S2100 to S2500 are re-executed to obtain the target feature dimension set corresponding to the condition combination, thereby updating the target feature dimension set and outputting the updated target feature dimension set.

[0160] Continuing with the above example, for condition combination 1, where the coefficient of the objective function is 0.85 and the preset tolerance range is ±10nm, the target diameter set (i.e., the target characteristic size set) obtained in step S2500 is used as the first diameter set (i.e., the first characteristic size set) in step S2100, and the above steps S2100 to S2500 are re-executed to obtain a new target diameter set. Similarly, for condition combination 2, where the coefficient of the objective function is 0.90 and the preset tolerance range is ±20nm, a new target diameter set is also obtained. Each target diameter set is offset to analyze the change of diffraction efficiency with diameter offset.

[0161] In one example, if Fig. 9As shown in FIG. 10 , it shows the curves of the diffraction efficiency of the target diameter sets corresponding to the 18 condition combinations after the offset occurs. In order to facilitate further analysis, we analyze the target diameter sets corresponding to the condition combinations with the same preset tolerance range in the condition combination set separately, as shown in FIG. 10 (a), which shows the diffraction efficiency change curve of the target diameter set corresponding to the condition combination with a preset tolerance range (i.e., random error) of ±10nm in the condition combination set after the offset occurs, where the curve corresponding to old is the diffraction efficiency change curve of the target diameter set before the random error is not considered after the offset occurs. It can be seen that after the random error is considered, the change of diffraction efficiency is slower and the optical performance is better. As shown in FIG. 10 (b), it shows the diffraction efficiency change curve of the target diameter set corresponding to the condition combination with a preset tolerance range (i.e., random error) of ±20nm in the condition combination set after the offset occurs, where the curve corresponding to old is the diffraction efficiency change curve of the target diameter set before the random error is not considered after the offset occurs, it can be seen that after the random error is considered, the change of diffraction efficiency is slower and the optical performance is better.

[0162] According to an embodiment of the present application, after obtaining the target characteristic dimension set, by constructing a condition combination set, the target characteristic dimension set is used as a new first characteristic dimension set to recalculate a new target characteristic dimension set corresponding to each condition combination in the condition combination set, and the new target characteristic dimension set is used as a reference for actual production, thereby avoiding the problem of poor optical performance of the metasurface caused by random errors.

[0163] According to an embodiment of the present application, by determining the first characteristic size set of the metasurface, constructing multiple characteristic size sets according to the first characteristic size set and a preset tolerance range, calculating the diffraction efficiency of the metasurface of each characteristic size set to the incident light wave, constructing an objective function according to the first target diffraction efficiency and the diffraction efficiency of the metasurface of each characteristic size set to the incident light wave, and optimizing the size of the first characteristic size set according to the objective function to obtain and output the target characteristic size set. By incorporating the tolerance range into the design process of the target characteristic size set, the difference in optical performance of MOE products caused by systematic errors and random errors in the actual production process can be reduced, and the yield rate of MOE products can be improved.

[0164] <Electronic Equipment Embodiment>

[0165] Fig.11 FIG. 1 is a principle block diagram of an electronic device 1100 according to an embodiment of the present invention.

[0166] In this embodiment, if Fig.11As shown, the electronic device 1100 includes a memory 1110 and a processor 1120, wherein the memory 1110 is used to store executable instructions; the processor 1120 is used to operate according to the control of the instructions to execute the method described in any of the above method embodiments.

[0167] In one embodiment, the electronic device is Figure 1 Electronic equipment shown.

[0168] The present invention also provides a computer-readable storage medium having computer-executable instructions stored thereon, and when the executable instructions are executed by a processor, the method described in any of the above method embodiments is implemented.

[0169] The present invention may be a system, a method and / or a computer program product. The computer program product may include a computer-readable storage medium carrying computer-readable program instructions for causing a processor to implement various aspects of the present invention.

[0170] A computer-readable storage medium may be a tangible device that can hold and store instructions used by an instruction execution device. A computer-readable storage medium may be, for example, but not limited to, an electrical storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the foregoing. More specific examples of computer-readable storage media (a non-exhaustive list) include: a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), a static random access memory (SRAM), a portable compact disk read-only memory (CD-ROM), a digital versatile disk (DVD), a memory stick, a floppy disk, a mechanical encoding device, such as a punch card or a raised structure in a groove on which instructions are stored, and any suitable combination of the foregoing. As used herein, a computer-readable storage medium is not to be interpreted as a transient signal per se, such as a radio wave or other freely propagating electromagnetic wave, an electromagnetic wave propagating through a waveguide or other transmission medium (e.g., a light pulse through a fiber optic cable), or an electrical signal transmitted through a wire.

[0171] The computer-readable program instructions described herein can be downloaded from a computer-readable storage medium to each computing / processing device, or downloaded to an external computer or external storage device via a network, such as the Internet, a local area network, a wide area network, and / or a wireless network. The network can include copper transmission cables, optical fiber transmissions, wireless transmissions, routers, firewalls, switches, gateway computers, and / or edge servers. The network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and forwards the computer-readable program instructions for storage in the computer-readable storage medium in each computing / processing device.

[0172] The computer program instructions for performing the operation of the present invention may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-related instructions, microcode, firmware instructions, state setting data, or source code or object code written in any combination of one or more programming languages, including object-oriented programming languages, such as Smalltalk, C++, etc., and conventional procedural programming languages, such as "C" language or similar programming languages. Computer-readable program instructions may be executed entirely on a user's computer, partially on a user's computer, as an independent software package, partially on a user's computer, partially on a remote computer, or entirely on a remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer via any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., using an Internet service provider to connect via the Internet). In some embodiments, an electronic circuit, such as a programmable logic circuit, a field programmable gate array (FPGA), or a programmable logic array (PLA), may be personalized by utilizing the state information of the computer-readable program instructions, and the electronic circuit may execute the computer-readable program instructions, thereby realizing various aspects of the present invention.

[0173] Various aspects of the present invention are described herein with reference to the flow charts and / or block diagrams of the methods, devices (systems) and computer program products according to embodiments of the present invention. It should be understood that each box of the flow chart and / or block diagram and the combination of each box in the flow chart and / or block diagram can be implemented by computer-readable program instructions.

[0174] These computer-readable program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, thereby producing a machine, so that when these instructions are executed by the processor of the computer or other programmable data processing device, a device that implements the functions / actions specified in one or more boxes in the flowchart and / or block diagram is generated. These computer-readable program instructions can also be stored in a computer-readable storage medium, and these instructions cause the computer, programmable data processing device, and / or other equipment to work in a specific manner, so that the computer-readable medium storing the instructions includes a manufactured product, which includes instructions for implementing various aspects of the functions / actions specified in one or more boxes in the flowchart and / or block diagram.

[0175] Computer-readable program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other device so that a series of operating steps are performed on the computer, other programmable data processing apparatus, or other device to produce a computer-implemented process, thereby causing the instructions executed on the computer, other programmable data processing apparatus, or other device to implement the functions / actions specified in one or more boxes in the flowchart and / or block diagram.

[0176] The flowcharts and block diagrams in the accompanying drawings show the possible architecture, functions and operations of the systems, methods and computer program products according to multiple embodiments of the present invention. In this regard, each box in the flowchart or block diagram can represent a module, a program segment or a part of an instruction, and the module, a program segment or a part of an instruction contains one or more executable instructions for realizing the specified logical function. In some alternative implementations, the functions marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram and / or the flowchart, and the combination of the boxes in the block diagram and / or the flowchart can be implemented by a dedicated hardware-based system that performs the specified function or action, or can be implemented by a combination of dedicated hardware and computer instructions. It is well known to those skilled in the art that it is equivalent to implement it by hardware, implement it by software, and implement it by combining software and hardware.

[0177] Embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The terms used herein are selected to best explain the principles of the embodiments, practical applications, or technical advances in the marketplace, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein. The scope of the present invention is defined by the appended claims.

Claims

1. A tolerance optimization method for a metasurface, characterized in that: The method comprises: Determine a first characteristic size set of the metasurface; wherein the metasurface includes a plurality of sub-wavelength units, and the first characteristic size set includes a first characteristic size corresponding to each sub-wavelength unit in the plurality of sub-wavelength units; Constructing a plurality of characteristic dimension sets according to the first characteristic dimension set and a preset tolerance range; Calculating the diffraction efficiency of the metasurface of each characteristic size set for the incident light wave; Constructing an objective function according to the first target diffraction efficiency and the diffraction efficiency of the metasurface of each characteristic size set to the incident light wave; wherein the objective function reflects the difference between the diffraction efficiency of each characteristic size set in the plurality of characteristic size sets and the first target diffraction efficiency; According to the objective function, the first characteristic size set is optimized to obtain and output a target characteristic size set.

2. The method according to claim 1, characterized in that The step of optimizing the first characteristic size set according to the objective function to obtain and output a target characteristic size set includes: Optimizing the first characteristic size set according to the objective function; When the number of size optimizations of the first characteristic size set is greater than or equal to a preset number threshold, the target characteristic size set is obtained and output.

3. The method according to claim 1 or 2, characterized in that: The optimizing the size of the first characteristic size set comprises: The first characteristic size set is optimized by using a gradient optimization algorithm.

4. The method according to claim 1, characterized in that: The preset tolerance range includes an upper limit value and a lower limit value, and the multiple characteristic dimension sets are constructed according to the first characteristic dimension set and the preset tolerance range, including: Determine a second characteristic dimension set according to the first characteristic dimension set and the lower limit value; Determine a third characteristic dimension set according to the first characteristic dimension set and the upper limit value; The first characteristic dimension set, the second characteristic dimension set and the third characteristic dimension set are used as a plurality of constructed characteristic dimension sets.

5. The method according to claim 1, characterized in that Determining a first characteristic size set of the metasurface includes: Calculating a first light intensity distribution formed by the incident light wave passing through the metasurface with the initial phase distribution; determining a fourth diffraction efficiency according to the first light intensity distribution and the target light intensity distribution; According to the fourth diffraction efficiency, phase optimization is performed on the initial phase distribution to obtain a target phase distribution; According to a preset mapping relationship and the target phase distribution, a first characteristic size set corresponding to the target phase distribution is determined; wherein the preset mapping relationship reflects a mapping relationship between the phase and the characteristic size of the sub-wavelength unit.

6. The method according to claim 5, characterized in that The step of optimizing the initial phase distribution according to the fourth diffraction efficiency to obtain a target phase distribution includes: When the fourth diffraction efficiency is less than the second target diffraction efficiency, optimizing the initial phase distribution to obtain an optimized phase distribution; According to the optimized phase distribution, updating the initial phase distribution, and recalculating the fourth diffraction efficiency; When the fourth diffraction efficiency is greater than or equal to the second target diffraction efficiency, the target phase distribution is obtained.

7. The method according to claim 1, characterized in that The sub-wavelength unit is a cylinder, and the first characteristic size set of the metasurface is a cylinder diameter set.

8. The method according to claim 1, characterized in that After obtaining and outputting the target feature size set, the method further includes: By deviating at least one of the coefficient of the objective function and the preset tolerance range, a condition combination set is constructed; The target characteristic dimension set is used as a new first characteristic dimension set, and the target characteristic dimension set corresponding to each condition combination in the condition combination set is recalculated.

9. An electronic device comprising a memory and a processor, wherein the memory is used to store executable instructions; and the processor is used to operate according to the control of the instructions to execute the method according to any one of claims 1 to 8.

10. A computer-readable storage medium having computer-executable instructions stored thereon, characterized in that: When the executable instructions are executed by a processor, the method according to any one of claims 1 to 8 is implemented.

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