Method for designing metasurface unit structure and metasurface unit structure thereof

Abstract

The invention discloses a method for designing a metasurface unit structure and the metasurface unit structure. The method comprises the following steps: performing scanning parameter simulation on a candidate metasurface unit structure to obtain simulation data about phase modulation quantity and transmittance data; marking simulation data corresponding to the candidate metasurface unit structures which cannot be realized; the simulation data which are not marked are screened according to a preset rule, a final metasurface unit structure is obtained, and a metasurface unit comprises a silicon cylinder structure and a silicon circular ring structure arranged above the silicon cylinder structure. According to the scheme, the combination of the silicon cylinder structure and the silicon circular ring structure is adopted as the metasurface unit, the design freedom degree is increased, and therefore the metasurface unit structure with the higher transmittance can be obtained on the premise that 0-2 pi phase coverage is guaranteed.

Description

Technical Field

[0001] The present disclosure generally relates to the field of optical technology. More specifically, the present disclosure relates to a method for designing a metasurface unit structure and a metasurface unit structure obtained by the method. Background Art

[0002] A metasurface is a two-dimensional array of micro-nano structures that can regulate the amplitude, phase and other parameters of the incident light wave by changing the characteristic dimensions of the unit structure. Due to its small size and light weight, metasurfaces can effectively reduce the volume of optical systems, and are therefore widely used in consumer electronics, communications, security, medical and other fields. At present, the metasurface unit structures designed by the industry are mostly prismatic or cylindrical structures, and their structural parameters are usually determined by scanning parameter simulation of the unit structure to produce the required phase delay in the range of 0 to 2π. This method establishes a structure library and then selects a suitable unit structure from the structure library according to the phase modulation requirements to achieve specific optical functions.

[0003] However, the transmittance of the metasurface unit in the prior art is not high enough in some intervals, which directly affects the overall efficiency of the metasurface device. Especially in application scenarios where large-range phase modulation and high transmittance need to be achieved simultaneously, the traditional single structure design method is difficult to meet the requirements. This technical defect limits the application potential of metasurfaces in high-efficiency optical systems. Therefore, there is an urgent need for a new metasurface unit structure design method that can not only ensure the full phase modulation range of 0 to 2π, but also improve the transmittance of the unit structure in each phase interval, thereby improving the overall performance of the metasurface device. Summary of the invention

[0004] In order to at least solve one or more of the technical problems mentioned above, the present disclosure proposes a method for designing a metasurface unit structure and a metasurface unit structure solution obtained by the method in multiple aspects.

[0005] In a first aspect, the present disclosure provides a method for designing a metasurface unit structure, the method comprising: performing scanning parameter simulation on a candidate metasurface unit structure to obtain simulation data on phase modulation and transmittance data, wherein the candidate metasurface unit structure comprises a substrate and a metasurface unit arranged on the substrate, and the phase modulation and transmittance data correspond to the candidate metasurface unit structure under different characteristic parameter combinations; marking the simulation data corresponding to the candidate metasurface unit structure that cannot be realized; and screening the unmarked simulation data according to predetermined rules to obtain a final metasurface unit structure, wherein the metasurface unit comprises a silicon cylindrical structure and a silicon ring structure arranged above the silicon cylindrical structure.

[0006] In some embodiments, the substrate is a glass plate.

[0007] In some embodiments, the substrate is a D263T glass plate.

[0008] In some embodiments, the silicon cylindrical structure and the silicon ring structure are made of amorphous silicon.

[0009] In some embodiments, the characteristic parameters of the unit structure include: an inner diameter of the ring, an outer diameter of the ring, a height of the ring, a radius of the cylinder and a height of the cylinder, wherein the inner diameter of the ring represents the diameter of the inner circle of the ring, and the outer diameter of the ring represents the diameter of the outer circle of the ring.

[0010] In some embodiments, the unrealizable candidate metasurface unit structures include: a structure in which the inner diameter of the ring is greater than or equal to the radius of the cylinder, or a structure in which the outer diameter of the ring is equal to the inner diameter of the ring.

[0011] In some embodiments, the predetermined rule includes: the phase modulation amount of each unit structure can cover 0-2π, the phase difference between each unit structure is less than a set value and / or the transmittance is higher than a predetermined threshold.

[0012] In some embodiments, the substrate has a size of 450 nm×450 nm×5000 nm.

[0013] In some embodiments, the silicon cylindrical structure is 600 nm high.

[0014] In some embodiments, the silicon ring structure is 200 nm high.

[0015] In some embodiments, the cylinder radius scanning range is 50 to 150 nm, and the scanning step length is 2 nm.

[0016] In some embodiments, the scanning range of the inner diameter of the ring is 20 to 300 nm, and the scanning step length is 20 nm.

[0017] In some embodiments, the scanning range of the outer diameter of the ring is 100 to 360 nm, and the scanning step length is 20 nm.

[0018] In some embodiments, the set value is 0.75 rad.

[0019] In a second aspect, the present disclosure provides a metasurface unit structure obtained using the method described in the first aspect, the structure comprising: a substrate and a metasurface unit arranged on the substrate; wherein the metasurface unit comprises: a silicon cylindrical structure and a silicon ring structure arranged above the silicon cylindrical structure.

[0020] Through the method for designing a metasurface unit structure as provided above and the metasurface unit structure obtained by the method, the disclosed embodiment can increase the degree of design freedom by adopting a combination of a silicon cylindrical structure and a silicon ring structure as a metasurface unit, thereby obtaining a unit structure in which both the phase modulation amount and the transmittance meet the requirements. Further, in some embodiments, by screening the units according to the transmittance, a metasurface unit with higher transmittance can be obtained while ensuring 0-2π phase coverage. Furthermore, in some embodiments, by setting a specific scanning parameter range and step size, a metasurface unit structure that meets the requirements can be obtained more accurately. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] By reading the detailed description below with reference to the accompanying drawings, the above and other objects, features and advantages of the exemplary embodiments of the present disclosure will become readily understood. In the accompanying drawings, several embodiments of the present disclosure are shown in an exemplary and non-limiting manner, and the same or corresponding reference numerals represent the same or corresponding parts, wherein:

[0022] Figure 1 A schematic diagram showing a metasurface unit structure according to an embodiment of the present disclosure;

[0023] Figure 2 An exemplary flow chart of a method for designing a super-surface unit structure according to an embodiment of the present disclosure is shown;

[0024] Figure 3 A schematic diagram showing characteristic parameters of a supersurface unit structure according to an embodiment of the present disclosure is shown;

[0025] Figure 4 A schematic diagram of a super surface unit structure in which the inner diameter of a ring is smaller than the radius of a cylinder according to an embodiment of the present disclosure is shown;

[0026] Figure 5 A schematic diagram of a structure in which the inner diameter of a circular ring is greater than or equal to the radius of a cylinder according to an embodiment of the present disclosure is shown;

[0027] Figure 6 A schematic diagram showing the distribution of phase modulation and transmittance corresponding to each characteristic parameter unit according to an embodiment of the present disclosure is shown;

[0028] Figure 7 A schematic diagram showing deleted and retained unit structure data according to an embodiment of the present disclosure; and

[0029] Figure 8 A schematic diagram comparing the phase modulation amount and transmittance corresponding to the unit structure obtained according to the embodiment of the present disclosure with the unit structure obtained by the conventional method is shown. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the present disclosure to clearly and completely describe the technical solutions in the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present disclosure.

[0031] It should be understood that the terms "include" and "comprising" used in the specification and claims of the present disclosure indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or collections thereof.

[0032] It should also be understood that the terms used in this disclosure are only for the purpose of describing the predetermined embodiments and are not intended to limit the disclosure. As used in this disclosure and claims, the singular forms of "a", "an", and "the" are intended to include the plural forms unless the context clearly indicates otherwise. It should also be further understood that the term "and / or" used in this disclosure and claims refers to any combination of one or more of the associated listed items and all possible combinations, including these combinations.

[0033] As used in this specification and claims, the term "if" may be interpreted as "when" or "upon" or "in response to determining" or "in response to detecting," depending on the context. Similarly, the phrase "if it is determined" or "if [described condition or event] is detected" may be interpreted as meaning "upon determination" or "in response to determining" or "upon detection of [described condition or event]" or "in response to detecting [described condition or event]," depending on the context.

[0034] As described above, a metasurface is a two-dimensional array of micro-nano structures, which can regulate the amplitude, phase and other parameters of the incident light wave by changing the characteristic size of the unit structure. At present, the metasurface unit structures designed by the industry are mostly prism or cylindrical structures, and their structural parameters are usually determined by scanning the unit structure to produce the required phase delay in the range of 0 to 2π. However, the transmittance of the metasurface unit obtained by this method in some intervals is not high enough, which affects the overall efficiency of the metasurface device. To solve this problem, the present invention proposes a new metasurface unit structure design method. This method uses a combination of silicon cylindrical structure and silicon ring structure as a metasurface unit, obtains phase modulation and transmittance data by scanning the candidate metasurface unit structure, and then selects the final metasurface unit structure through specific rules. This method not only increases the design freedom, but also can obtain a metasurface unit with higher transmittance under the premise of ensuring 0 to 2π phase coverage.

[0035] The specific implementation of the present disclosure is described in detail below with reference to the accompanying drawings.

[0036] Figure 1 FIG. 2 shows a schematic diagram of a super surface unit structure according to an embodiment of the present disclosure. Figure 1 As shown in , the metasurface unit structure includes a substrate 12 and a metasurface unit disposed on the substrate 12. The metasurface unit includes a silicon cylindrical structure 11 and a silicon ring structure 10 disposed above the silicon cylindrical structure 11. In one embodiment, the substrate 12 may be a D263T glass plate, whose refractive index at a wavelength of 940nm may be 1.51. The materials of the silicon cylindrical structure 11 and the silicon ring structure 10 may both be amorphous silicon, whose refractive index at a wavelength of 940nm may be 3.6. This structural design may increase the design freedom of the metasurface unit, so that the phase modulation amount and transmittance may be optimized simultaneously by adjusting the size parameters of the cylinder and the ring. In one embodiment, the size of the substrate 12 disclosed in the present invention may be 450nm×450nm×5000nm, the height of the silicon cylindrical structure 11 may be 600nm, and the height of the silicon ring structure 10 may be 200nm. Through this combined structure, a metasurface unit with higher transmittance may be obtained under the premise of ensuring 0-2π phase coverage.

[0037] Figure 2 FIG. 2 shows an exemplary flow chart of a method for designing a super surface unit structure according to an embodiment of the present disclosure. Figure 2 As shown, the method comprises the following steps:

[0038] At step S202, a scanning parameter simulation is performed on the candidate metasurface unit structure to obtain simulation data about the phase modulation amount and transmittance data. In one embodiment, the candidate metasurface unit structure under different characteristic parameter combinations can be simulated. As an example, the aforementioned characteristic parameters may include the inner diameter of the ring, the outer diameter of the ring, the height of the ring, the radius of the cylinder, and the height of the cylinder. In a specific embodiment, the scanning parameter simulation of the candidate metasurface unit structure can be performed under periodic boundary conditions. Specifically, the unit structure can be simulated using the finite difference time domain method ("FDTD"). In the simulation setting, a plane wave light source with an upward propagation direction can be placed inside the substrate. In order to obtain phase modulation and transmittance data, a monitor can be placed 470nm above the unit structure. This simulation setting can accurately simulate the modulation effect of the metasurface unit on the incident light, thereby obtaining reliable phase modulation and transmittance data.

[0039] Next, at step S204, the simulation data corresponding to the candidate hypersurface unit structures that cannot be realized are marked. In one embodiment, the candidate hypersurface unit structures that cannot be realized may include a structure in which the inner diameter of the ring is greater than or equal to the radius of the cylinder, or a structure in which the outer diameter of the ring is equal to the inner diameter of the ring. These structures cannot be manufactured in practice or have no practical significance, so they need to be marked and excluded in subsequent steps.

[0040] Thereafter, at step S206, the unlabeled simulation data is screened according to a predetermined rule to obtain the final metasurface unit structure. In one embodiment, the predetermined rule may include: the phase modulation amount of each unit structure can cover 0 to 2π, the phase difference between each unit structure is less than a set value, and / or the transmittance is higher than a predetermined threshold. This screening method can ensure that the obtained metasurface unit structure can meet the phase modulation requirements and ensure a high transmittance.

[0041] In order to facilitate comparison and show the technical advantages of the disclosed solution, the phase modulation amount and transmittance data corresponding to the metasurface unit obtained by the conventional method and the disclosed solution are shown in the form of tables below, where Table 1 is the conventional method and Table 2 is the disclosed solution.

[0042] Table 1 Phase modulation and transmittance data corresponding to the unit obtained by conventional method

[0043]

[0044]

[0045] Table 2 Phase modulation and transmittance data corresponding to the metasurface unit structure obtained by the present invention

[0046]

[0047] By comparing the data in Table 1 and Table 2, it can be clearly seen that the disclosed solution has significant advantages over conventional methods. Table 1 shows the unit structure obtained by the conventional method, in which the transmittance drops to 0.8804 when the phase modulation amount is 3.0614rad, which is the lowest point in the entire phase modulation range. In contrast, the unit structure obtained by the disclosed solution shown in Table 2 still maintains a high transmittance of 0.966 at a similar phase modulation amount (3.4864rad). More noteworthy is that the disclosed solution maintains a relatively high transmittance within the entire phase modulation range (0~2π), with the lowest value of 0.9054, which is higher than the lowest value of 0.8804 of the conventional method. In addition, the disclosed solution achieves extremely high transmittances exceeding 0.98 at multiple phase points, especially reaching 0.9997 at 0.7461rad. In addition, at the same cylindrical radius, the disclosed solution achieves higher transmittances than conventional methods. These data fully prove that the metasurface unit structure design proposed in the present disclosure can not only cover the full phase modulation range, but also maintain a higher and more uniform transmittance in the entire range, thereby significantly improving the overall performance and efficiency of the metasurface device. It can be further seen that through the method 200 disclosed in the present disclosure, a metasurface unit structure with excellent performance can be systematically designed, and compared with traditional structures such as single cylinders or prisms, a higher degree of design freedom and better optical performance can be obtained.

[0048] Figure 3 FIG. 2 shows a schematic diagram of characteristic parameters of a super surface unit structure according to an embodiment of the present disclosure. Figure 3 As shown, the metasurface unit structure includes a silicon ring structure (left) and a silicon cylinder structure (right).

[0049] Specifically, for a silicon ring structure, its characteristic parameters may include: the inner diameter of the ring 21, which indicates the diameter of the inner circle of the ring; the outer diameter of the ring 22, which indicates the diameter of the outer circle of the ring; and the height of the ring 23, which indicates the height of the ring. Correspondingly, for a silicon cylinder structure, its characteristic parameters may include: the radius of the cylinder 24, which indicates the radius of the cylinder; and the height of the cylinder 25, which indicates the height of the cylinder.

[0050] In one embodiment, these characteristic parameters can be scanned and simulated within a specific range. For example, the scanning range of the cylinder radius 24 can be 50 to 150 nm, and the scanning step length can be 2 nm. The scanning range of the ring inner diameter 21 can be 20 to 300 nm, and the scanning step length can be 20 nm. The scanning range of the ring outer diameter 22 can be 100 to 360 nm, and the scanning step length can be 20 nm. In one embodiment, the height 25 of the silicon cylinder structure can be 600 nm, and the height 23 of the silicon ring structure can be 200 nm. These parameters can be adjusted according to specific application requirements.

[0051] By adjusting these characteristic parameters, the metasurface unit structure can be finely designed to obtain the desired phase modulation and transmittance characteristics. The multi-parameter design method disclosed herein can provide greater design freedom and help obtain a metasurface unit structure with better performance.

[0052] Figure 4 FIG. 2 shows a schematic diagram of a super surface unit structure in which the inner diameter of a ring is smaller than the radius of a cylinder according to an embodiment of the present disclosure. Figure 4 As shown, the structure includes a substrate, a silicon cylindrical structure disposed on the substrate, and a silicon ring structure located above the silicon cylindrical structure. In this embodiment, the inner diameter of the silicon ring structure is smaller than the radius of the silicon cylindrical structure, so that the ring can be stably placed on the cylinder. This configuration can ensure the stability and manufacturability of the super surface unit structure.

[0053] In one embodiment, the substrate can be a D263T glass plate. The materials of the silicon cylindrical structure and the silicon ring structure can both be amorphous silicon. This material selection can provide the desired refractive index characteristics at a wavelength of 940nm. The geometric parameters of the structure can be adjusted as needed. For example, the radius of the cylinder can vary in the range of 50 to 150nm, the inner diameter of the ring can vary in the range of 20 to 300nm, and the outer diameter of the ring can vary in the range of 100 to 360nm. The specific values ​​of these parameters can be determined through scanning simulation and screening processes to obtain optimal phase modulation and transmittance performance.

[0054] The disclosed cylinder and ring combination structural design can provide greater design freedom, so that the phase modulation amount and transmittance can be optimized at the same time. Compared with the traditional single cylinder or prism structure, this design can achieve higher transmittance while ensuring 0-2π phase coverage.

[0055] Figure 5 A schematic diagram of a structure in which the inner diameter of a ring is greater than or equal to the radius of a cylinder according to an embodiment of the present disclosure is shown. Figure 5 As shown, the structure includes a substrate, a silicon cylindrical structure disposed on the substrate, and a silicon ring structure located above the silicon cylindrical structure. In this embodiment, the inner diameter of the silicon ring structure is greater than or equal to the radius of the silicon cylindrical structure. This configuration is not achievable in practice because the ring cannot be stably placed on the cylinder. This situation represents an invalid structure that needs to be marked and excluded during the design process.

[0056] In one embodiment, this combination of geometric parameters may occur when performing a parameter scanning simulation. For example, this situation occurs when the inner diameter of the ring is set to 200nm, the outer diameter of the ring is 300nm, and the cylinder radius is only 50nm. Another situation that needs to be marked is that the inner diameter of the ring is equal to the outer diameter of the ring, which will cause the thickness of the ring to be approximately 0, which is also meaningless.

[0057] It can be seen that identifying and marking these unrealizable structures is an important step in the design method disclosed herein. By excluding these invalid structures, it can be ensured that the metasurface unit structure finally selected can be actually manufactured and used. This step reflects the rigor and practicality of the design method disclosed herein. By systematically considering all possible parameter combinations and excluding unfeasible solutions, it is possible to more effectively screen out metasurface unit structures that can both meet optical performance requirements and ensure manufacturability. It can be seen that the design method disclosed herein can not only improve design efficiency, but also avoid problems that may be encountered in subsequent manufacturing processes, thereby accelerating the development and application of metasurface devices.

[0058] Figure 6 FIG. 2 shows a schematic diagram of the phase modulation amount and transmittance distribution corresponding to each characteristic parameter unit according to an embodiment of the present disclosure. Figure 6 As shown, this figure shows the relationship between the phase modulation amount (horizontal axis) and the transmittance (vertical axis).

[0059] Specifically, in the Figure 6 In the figure, the scattered dots represent the performance data of various metasurface unit structures obtained by scanning parameters in the disclosed method, while the solid line represents the performance curve of the conventional scanning parameter unit. The following key points can be observed from the figure:

[0060] First, the data points (scatter points) obtained by the design method disclosed in the present invention cover a wider range of phase-transmittance combinations, which shows that the method disclosed in the present invention provides greater design freedom. Secondly, in the entire 0-2π phase modulation range, the transmittance of many data points obtained by the design method disclosed in the present invention is higher than the curve of the conventional method, especially in the area where the phase modulation amount is about 3 rad. In addition, the performance curve of the conventional method shows a significant decrease in transmittance in certain phase modulation amount intervals (such as about 3 rad), while the method disclosed in the present invention still maintains a relatively high transmittance selection in these intervals. As a result, the design method disclosed in the present invention generates a large number of candidate structures, providing abundant choices for subsequent screening.

[0061] In one embodiment, such a distribution diagram can be used for further screening. For example, unit structures with the highest possible transmittance while ensuring 0-2π phase coverage can be selected. Specifically, a transmittance threshold, such as 0.9, can be set, and unit structures with uniform phase distribution can be selected based on this.

[0062] pass Figure 6 This visual comparison can intuitively demonstrate the advantages of the disclosed method over conventional methods, namely, the ability to search for the optimal metasurface unit structure in a larger parameter space, thereby achieving higher transmittance performance while ensuring the required phase modulation. This improvement is of great significance for improving the overall efficiency of metasurface devices.

[0063] Figure 7 Schematic diagram of deleted and retained unit structure data according to the embodiment of the present disclosure is shown. Figure 7 As shown, the figure shows the relationship between the phase modulation amount (horizontal axis) and the transmittance (vertical axis), and distinguishes between usable unit structures and unrealizable unit structures.

[0064] exist Figure 7 In the figure, the dots with solid lines represent the performance curves of conventional scanning units; the small dots represent available unit structure data, and the “×” mark represents unavailable unit structure data. Figure 7 It can be observed that:

[0065] First, the unrealizable unit structures (marked with "×") are mainly distributed in the upper half of the figure, especially in the high transmittance area. This shows that during the design process, some structures that seem to have excellent performance but are actually impossible to manufacture are successfully identified and excluded. Secondly, the available unit structures (small dots) cover the entire 0-2π phase modulation range, and there are high transmittance options in most phase intervals. Thirdly, in some phase intervals, especially close to 3rad, the transmittance of the available unit structure is higher than the performance curve of the conventional method. This shows that the method disclosed in the present invention can provide better performance in these key intervals.

[0066] It can be seen that after deleting the unrealizable unit structures, the solution disclosed in the present invention still retains a large number of available unit structures, providing sufficient candidate solutions for subsequent optimization selection.

[0067] In one embodiment, this classification and screening process can be achieved by the following steps:

[0068] First, mark those structures that are geometrically unrealizable, such as structures where the inner diameter of the ring is greater than or equal to the radius of the cylinder, or structures where the outer diameter of the ring is equal to the inner diameter of the ring.

[0069] Then, the remaining available structures can be further screened according to predetermined rules. For example, unit structures can be selected that ensure 0-2π phase coverage, have a phase difference between units that is less than a set value (such as 0.75 rad), and have a transmittance as high as possible.

[0070] It can be seen that the above method disclosed in the present invention can not only effectively eliminate unfeasible designs, but also find the best solution among feasible designs. Through this systematic screening process, it can be ensured that the finally selected metasurface unit structure has both ideal optical performance and can be actually manufactured and applied.

[0071] Figure 8 The figure shows a schematic diagram comparing the phase modulation amount and transmittance corresponding to the unit structure obtained according to the embodiment of the present disclosure with the unit structure obtained by the conventional method. Figure 8 As shown, the figure shows the relationship between the phase modulation amount (horizontal axis) and the transmittance (vertical axis), and compares the performance of the metasurface unit structure obtained by the disclosed method (solid circle line) and the conventional method ("×" marked line).

[0072] from Figure 8 The following information can be observed:

[0073] Phase coverage: Both methods can achieve a complete phase modulation range of 0 to 2π, meeting the basic requirements of metasurface design.

[0074] Transmittance performance: The unit structure obtained by the method disclosed in this disclosure shows higher transmittance at most phase points. In particular, in the phase range of about 2.5rad to 4rad, the technical advantage of the disclosed solution is more obvious.

[0075] Performance stability: The curve obtained by the method disclosed in the present invention is smoother overall, and the fluctuation of transmittance is smaller, which means that more consistent transmittance performance can be obtained under different phase modulation amounts.

[0076] Minimum transmittance: At the lowest point (about 2 rad), the transmittance of the disclosed method is still maintained above 0.9, while the transmittance of the conventional method at the corresponding position drops to about 0.87.

[0077] High transmittance range: In multiple phase ranges (such as 0-1 rad, 4-6 rad), the method disclosed in the present invention can achieve a transmittance close to 1, which is better than conventional methods.

[0078] In one embodiment, the above performance improvement can be achieved by:

[0079] A combination of silicon cylindrical structure and silicon ring structure is used as the metasurface unit to increase the design freedom. Through a fine parameter scanning and screening process, such as setting the cylindrical radius scanning range to 50-150nm (step length 2nm), the ring inner diameter scanning range to 20-300nm (step length 20nm), and the ring outer diameter scanning range to 100-360nm (step length 20nm). Finally, strict screening rules are applied, such as requiring the phase difference between each unit to be less than 0.75rad, while ensuring that the transmittance is as high as possible.

[0080] In summary, the disclosed solution can not only improve the overall transmittance while ensuring full phase coverage, but also achieve significant performance improvement in key phase intervals (such as areas where conventional methods performed poorly before). This is of great significance for improving the overall efficiency and performance of metasurface devices, and can be widely used in various optical systems that require high-efficiency phase control.

[0081] Although multiple embodiments of the present disclosure have been shown and described herein, it will be apparent to those skilled in the art that such embodiments are provided by way of example only. Those skilled in the art may think of many changes, modifications, and alternatives without departing from the thought and spirit of the present disclosure. It should be understood that in the process of practicing the present disclosure, various alternatives to the embodiments of the present disclosure described herein may be adopted. The attached claims are intended to define the scope of protection of the present disclosure, and therefore cover equivalents or alternatives within the scope of these claims.

Claims

1. A method for designing a metasurface unit structure, characterized in that: include: Performing parameter scanning simulation on a candidate metasurface unit structure to obtain simulation data on phase modulation and transmittance data, wherein the candidate metasurface unit structure includes a substrate and a metasurface unit disposed on the substrate, and the phase modulation and transmittance data correspond to the candidate metasurface unit structure under different characteristic parameter combinations; Marking simulation data corresponding to candidate metasurface unit structures that cannot be realized; as well as The unlabeled simulation data are screened according to a predetermined rule to obtain a final super surface unit structure, wherein the super surface unit includes a silicon cylindrical structure and a silicon ring structure arranged above the silicon cylindrical structure.

2. The method according to claim 1, characterized in that The material of the silicon cylindrical structure and the silicon ring structure is amorphous silicon.

3. The method according to claim 1, characterized in that The characteristic parameters of the unit structure include: an inner diameter of the ring, an outer diameter of the ring, a height of the ring, a radius of the cylinder and a height of the cylinder, wherein the inner diameter of the ring represents the diameter of the inner circle of the ring, and the outer diameter of the ring represents the diameter of the outer circle of the ring.

4. The method according to claim 1, characterized in that The candidate supersurface unit structures that cannot be realized include: a structure in which the inner diameter of the ring is greater than or equal to the radius of the cylinder, or a structure in which the outer diameter of the ring is equal to the inner diameter of the ring.

5. The method according to claim 1, characterized in that The predetermined rules include: the phase modulation amount of each unit structure can cover 0-2π, the phase difference between each unit structure is less than a set value and / or the transmittance is higher than a predetermined threshold.

6. A supersurface unit structure obtained by any method according to claims 1-5, characterized in that: include: A substrate and a metasurface unit disposed on the substrate; Wherein, the super surface unit includes a silicon cylindrical structure and a silicon ring structure arranged above the silicon cylindrical structure.

Images