A rapid modeling and design method for metalens based on object-oriented thinking

Abstract

The present invention provides a two-dimensional meta-lens rapid modeling and design method, comprising determining the shape of a nano-unit and geometric parameters corresponding to the shape, setting the required wavelength of incident light λ and the period P of the nano-unit; performing simulation scanning on the geometric parameters of the nano-unit to obtain the phase difference and transmittance generated by different geometric parameters of each nano-unit to the wavelength of incident light, selecting appropriate nano-units according to requirements and putting them into a database for constructing a meta-lens; arranging the obtained nano-units on a substrate according to a meta-lens construction formula to complete the design of the meta-lens; the present invention enables each nano-unit arranged on the substrate to be taken out from the database according to requirements, and then arranged on the substrate according to the meta-lens construction formula, thereby completing the design of the meta-lens.

Description

Technical Field

[0001] The invention relates to the field of lens design, and in particular to a rapid modeling and design method of a meta-lens based on an object-oriented concept. Background Art

[0002] Traditional lenses mainly control the optical phase through wavefront accumulation, which usually makes the lens too thick and the optical components extremely bulky. This is contrary to the development trend of modern optical instruments towards miniaturization, micro-miniaturization, multi-functional integration and low cost. Therefore, it is particularly important to obtain a new imaging principle and method for the development of optical technology.

[0003] The emergence of meta-lenses in recent years has brought hope for breaking through the limitations of traditional optical lenses. It is designed with artificial synthetic materials and can freely change various optical parameters according to people's needs. The relevant arrangement method can meet the arbitrary control of the phase. The meta-lens is small in size and can achieve high-resolution imaging, which is a subversive change for traditional lenses. As we require meta-lenses to have more and more subtle functions, we need to have a thorough understanding of each unit structure. Existing software, such as FDTD Solutions, comsol, CST Studio Suite, etc., selects unit structures and sets parameters according to requirements when constructing meta-lenses. This is mainly a process-oriented thinking. However, for process-oriented modeling, a nano-unit parameter scan must be performed for each simulation, and the different ranges and precisions will cause certain errors in the final designed meta-lens, mainly due to too few data sets and the phase may not be 100% consistent. Summary of the invention

[0004] In view of the shortcomings in the prior art, the present invention provides a rapid modeling and design method of a metalens based on an object-oriented concept, so that each nano-unit arranged on a substrate can be taken out from a database as required, and then arranged on the substrate through a metalens construction formula, thereby completing the design of the metalens.

[0005] The present invention achieves the above technical objectives through the following technical means.

[0006] A two-dimensional meta-lens rapid modeling and design method comprises the following steps:

[0007] Step 1: Determine the shape of the nanounit and the geometric parameters corresponding to the shape, set the wavelength of the required incident light λ and the period P of the nanounit;

[0008] Step 2: simulate and scan the geometric parameters of the nano-units to obtain the phase difference and transmittance generated by the different geometric parameters of each nano-unit for the incident light band, and select appropriate nano-units according to the requirements and put them into the database for constructing the meta-lens;

[0009] Step 3: Specify the focal length and size of the designed metalens, select the center focusing formula in the construction formula, arrange the nanounits obtained in step 2 on the substrate according to the metalens construction formula, and complete the design of the metalens.

[0010] Preferably, the nano unit is in the shape of a cylinder or a cuboid.

[0011] Preferably, the geometric parameter is the radius R of a cylinder or the length L and width W of a cuboid.

[0012] Preferably, in the step 2, a numerical simulation method is used to simulate and scan the geometric parameters of the nano-unit.

[0013] Preferably, the database is MySql or Oracle.

[0014] Preferably, the meta-lens construction formula includes a central single focus focusing formula:

[0015]

[0016] Among them, (x, y) is the coordinate of each nanometer unit, φ(x, y) is the phase difference of the nanometer unit relative to the center position of the metalens, λ is the incident wavelength, f is the focal length of the metalens, and x and y represent the coordinates of the unit structure position relative to the center point.

[0017] Preferably, the meta-lens construction formula includes an eccentric single focus focusing formula:

[0018]

[0019] Where (x1, y1) is the coordinate of the eccentric focus, f1 is the focal length, which is defined as the distance from the focus to the center of the lens, (x, y) is the coordinate of each nanometer unit, φ(x, y) is the phase difference of the nanometer unit relative to the center position of the lens, and λ is the incident wavelength.

[0020] Beneficial effects of the present invention:

[0021] The present invention firstly abstracts and summarizes the unit structure, so that people can quickly know the basic properties of the unit structure; secondly, each unit structure is instantiated and marked, so that the function that each unit structure can achieve can be clearly known; thirdly, by storing the data of each unit structure, it can be directly called when constructing a meta-lens, so as to facilitate the rapid establishment of a model. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A schematic diagram of the generalized Snell's law of a rapid modeling and design method of a metalens based on object-oriented thinking according to an embodiment of the present invention.

[0023] Figure 2 It is a flowchart of rapid modeling of a metalens according to an embodiment of the present invention, wherein (a) is a schematic diagram of nanounit properties, (b) is a front view of a nanounit, (c) is a schematic diagram of metalens properties, and (d) is a schematic diagram of metalens simulation.

[0024] Figure 3 Schematic diagram of rapid modeling and effect of a metalens of a cylindrical nanounit according to an embodiment of the present invention, wherein (a) is a schematic diagram of the properties of the nanounit, (b) is a schematic diagram of the phase of the nanounit, (c) is a schematic diagram of the focusing of the metalens in the xy and xz planes, and (d) is a schematic diagram of the field strength in the x and y directions at the focus.

[0025] Figure 4 Schematic diagram of rapid modeling and effect of a metalens of a cubic nanounit according to an embodiment of the present invention, wherein (a) is a schematic diagram of the properties of the nanounit, (b) is a schematic diagram of the phase of the nanounit, (c) is a schematic diagram of the focusing of the metalens in the xy and xz planes, and (d) is a schematic diagram of the field intensity in the x and y directions at the focus.

[0026] Figure 5 Schematic diagram of the rapid modeling and effect model of the meta-lens of the triangular prism nano-unit according to an embodiment of the present invention, wherein (a) is a schematic diagram of the properties of the nano-unit, (b) is a schematic diagram of the phase of the nano-unit, (c) is a schematic diagram of the focusing of the meta-lens in the xy and xz planes, and (d) is a schematic diagram of the field intensity in the x and y directions at the focus. DETAILED DESCRIPTION

[0027] In order to make the above-mentioned purpose, features and advantages of the present invention more obvious and easy to understand, the specific implementation of the present invention is described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific implementation disclosed below.

[0028] The following is combined with Figures 1 to 5 , a two-dimensional meta-lens rapid modeling and design method according to an embodiment of the present invention is described in detail.

[0029] A two-dimensional meta-lens rapid modeling design method according to an embodiment of the present invention is as follows: Figure 1 As shown, the design of the unit structure relies on the generalized Snell's law (1):

[0030] [k0n i sin(θ i )dx+(φ+dφ)]-[k0n t sin(θ t )dx+φ]=0

[0031] where θ i represents the refraction angle, φ and φ+dφ represent the sudden phase at the intersection of the two paths and the metasurface interface, dx represents the distance between the two intersections (infinitesimal), and n i and n t They represent the refractive index of the materials in the incident area and the transmission area respectively, and k0 represents the wave vector of the incident light in vacuum (k0=λ0 / 2).

[0032] A two-dimensional meta-lens rapid modeling and design method according to an embodiment of the present invention specifically includes the following steps:

[0033] Step 1: Determine the shape of the nanounit, which can be a cylinder, a cuboid or other shapes, and further determine the corresponding geometric parameters, which can be the radius R of the cylinder, the length L and width W of the cuboid, and set the wavelength of the required incident light λ and the period P of the nanounit;

[0034] Step 2: Use numerical simulation method to simulate and scan the geometric parameters of nano-units to obtain the phase difference and transmittance of the incident light band caused by different geometric parameters of each nano-unit, and select appropriate nano-units according to requirements and put them into the database for constructing meta-lens;

[0035] The database is constructed by an object-oriented language, which can be Java, C++ or other languages. The characteristics of the object-oriented language are to abstract the geometric parameters of the nano unit, instantiate it in the program, and store the data scanned by the parameters in the database. The database for storing data can be MySql, Oracle or other databases.

[0036] Step 3: Arrange the nano-units obtained in step 2 on the substrate according to the meta-lens construction formula to complete the design of the meta-lens.

[0037] The meta-lens construction formula includes the central single focus focusing formula:

[0038]

[0039] Among them, (x, y) is the coordinate of each nanounit relative to the center of the lens, φ(x, y) is the phase difference of the nanounit relative to the center position of the metalens, λ is the incident wavelength, and f is the focal length of the metalens.

[0040] The meta-lens construction formula includes the eccentric single focus focusing formula:

[0041]

[0042] Where (x1, y1) is the coordinate of the eccentric focus. f1 is the focal length, defined as the distance from the focus to the center of the lens, (x, y) is the coordinate of each nanometer unit, φ(x, y) is the phase difference of the nanometer unit relative to the center of the lens, and λ is the incident wavelength.

[0043] Embodiment 1

[0044] Step 1: Use Java language in IntelliJ IDEA environment to construct the cylindrical unit structure, such as Figure 3 As shown in (a), the shape coefficient is index = 1 at this time. Each time a unit structure id is created, it is incremented by 1 to form a unit structure tag, whose basic attributes are the center coordinates (x, y), phase phase, radius radius and height height; the incident light λ is set to 660nm, the period P of the nano unit is set to 450nm, the substrate material is selected as SiO2, and the unit structure material is selected as Si.

[0045] Step 2: Perform parameter scans on the radius and height of the cylindrical unit structure to obtain the phase change curve when the height is 1.3um and the radius is from 0.05um to 0.15um, as well as the corresponding curve of the phase phase required by the metalens and the metalens position (x, y), and store the data in the MySql database.

[0046] Step 3: We set the focal length f of the meta-lens to 80um, the lens size to 10.5um in diameter, and arrange the unit structure on the substrate as required. The required parameters can be retrieved one by one from the MySql database to complete the design of the meta-lens, such as Figure 3 As shown in (c), in the simulation, the meta-lens designed with a cylindrical unit structure can focus normally, and obvious focus can be seen in both the xy plane and the xz plane. Figure 3 In (d), the energy distribution of the x and y axes can be seen. The energy at the focus is relatively concentrated, with a focusing efficiency of up to 65%.

[0047] Embodiment 2

[0048] Step 1: Use Java language in IntelliJ IDEA environment to construct the cube unit structure, such as Figure 4As shown in (a), the shape coefficient is index = 2. Each time a unit structure id is created, it is incremented by 1 to prevent confusion between unit structure ids of different shapes. The unit structure tag is formed. The basic attributes are the center coordinates (x, y), phase phase, square side length L and height height. The incident light λ is set to 660nm, the period P of the nano unit is set to 450nm, the substrate material is selected as SiO2, and the unit structure material is selected as Si.

[0049] Step 2: Perform parameter scanning on the square side length L and height height of the cylindrical unit structure, and obtain the phase change curve when the square side length L is from 0.1um to 0.3um when the height is 1.3um, as well as the corresponding curve of the phase phase required by the meta-lens and the position (x, y) of the meta-lens, and store the data in the MySql database;

[0050] Step 3: We set the focal length f of the meta-lens to 80um, the lens size to 10.5um in diameter, and arrange the unit structure on the substrate as required. The required parameters can be retrieved one by one from the MySql database to complete the design of the meta-lens, such as Figure 4 As shown in (c), in the simulation, the meta-lens designed with a cube unit structure can focus normally, and obvious focus can be seen in both the xy plane and the xz plane. Figure 4 In (d), the energy distribution of the x and y axes can be seen. The energy at the focus is relatively concentrated, with a focusing efficiency of up to 64.4%.

[0051] Embodiment 3

[0052] Step 1: Use Java language in IntelliJ IDEA environment to construct the triangular prism unit structure, such as Figure 5 As shown in (a), the shape coefficient is index = 3. Each time a unit structure id is created, it is incremented by 1 to form a unit structure tag. The basic attributes are the center coordinates (x, y), phase phase, the relative coordinates of the three points of the triangular prism face (l1_x, l1_y; l2_x, l2_y; l3_x, l3_y) and height height. The incident light λ is set to 660nm, the period P of the nano unit is set to 450nm, the substrate material is selected as SiO2, and the unit structure material is selected as Si.

[0053] Step 2: Set the triangular prism face to an equilateral triangle, and perform parameter scanning with half the side length L and height height. You can get the phase change curve when the height is 1.3um and the half side length L changes from 0.05um to 0.15um, as well as the corresponding curve of the phase phase required by the meta-lens and the position (x, y) of the meta-lens, and store the data in the MySql database.

[0054] Step 3: We set the focal length f of the meta-lens to 80um, the lens size to 10.5um in diameter, and arrange the unit structure on the substrate as required. The required parameters can be retrieved one by one from the MySql database to complete the design of the meta-lens, such as Figure 5 As shown in (c), in the simulation, the meta-lens designed with the triangular prism unit structure can focus normally, and obvious focus can be seen in both the xy plane and the xz plane, as shown in Figure 5 In (d), the energy distribution of the x and y axes can be seen. The energy at the focus is relatively concentrated, with a focusing efficiency of up to 64.7%.

[0055] The present invention performs object-oriented modeling, and each nano-unit simulation will be stored in a database. First, the data set is guaranteed to be huge. The nano-units of the phase required by the meta-lens are directly obtained through the data set. The present invention is often not limited to the result of a single nano-unit simulation, but rather multiple nano-unit simulations under the same light field conditions, such as nano-unit simulations under a specified wavelength and a specified polarization state. The shape can be a cylinder, a triangular prism or a cuboid, and the phases obtained by parameter scanning complement each other, thereby reducing the error in meta-lens modeling.

[0056] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A rapid modeling and design method for two-dimensional meta-lens, It is characterized in that The steps include: Step 1: Determine the shape of the nanounit and the geometric parameters corresponding to the shape, set the wavelength of the required incident light λ and the period P of the nanounit; Step 2: simulate and scan the geometric parameters of the nano-units to obtain the phase difference and transmittance generated by the different geometric parameters of each nano-unit for the incident light band, and select appropriate nano-units according to the requirements and put them into the database for constructing the meta-lens; Step 3: Arrange the nano-units obtained in step 2 on the substrate according to the meta-lens construction formula to complete the design of the meta-lens. The meta-lens construction formula includes the eccentric single focus focusing formula: Where (x 1 ,y 1 ) is the coordinate of the eccentric focus, f 1 is the focal length, defined as the distance from the focus to the center of the lens, (x, y) is the coordinate of each nanometer unit, φ(x, y) is the phase difference of the nanometer unit relative to the center position of the lens, and λ is the incident wavelength.

2. The two-dimensional metalens rapid modeling and design method according to claim 1, It is characterized in that The shape of the nano unit is a cylinder or a cuboid.

3. The two-dimensional metalens rapid modeling and design method according to claim 2, It is characterized in that The geometric parameters are the radius R of a cylinder or the length L and width W of a cuboid.

4. The two-dimensional metalens rapid modeling and design method according to claim 1, It is characterized in that In the second step, a numerical simulation method is used to simulate and scan the geometric parameters of the nanometer unit.

5. The two-dimensional metalens rapid modeling and design method according to claim 1, It is characterized in that The database is Mysql or Oracle.

6. The two-dimensional metalens rapid modeling and design method according to claim 1, It is characterized in that The meta-lens construction formula includes the central single focus focusing formula: Among them, (x, y) is the coordinate of each nanometer unit, φ(x, y) is the phase difference of the nanometer unit relative to the center position of the metalens, λ is the incident wavelength, f is the focal length of the metalens, and x and y represent the coordinates of the unit structure position relative to the center point.

Images