Super-lens, super-lens structure parameter determination method, device and equipment, optical imaging equipment, storage medium and program product

Abstract

The invention provides a super lens, a super lens structure parameter determination method, device and equipment, optical imaging equipment, a storage medium and a program product. The super lens comprises a plurality of areas. Any region comprises a plurality of nano fins; wherein at least part of the area is used for focusing incident light with different wavelengths. The super lens is divided into a plurality of areas, and each area can form a super lens for focusing incident light with different wavelengths, so that wavelength division multiplexing is realized, and compared with a conventional geometrical optical lens for realizing wavelength division multiplexing, the super lens disclosed by the invention has the advantages of small volume and high integration level.

Description

Technical Field

[0001] This application relates to the field of optical technologies, and particularly to a metalens, a method for determining the structural parameters of a metalens, a device, an apparatus, an optical imaging device, a storage medium, and a program product. Background Art

[0002] In traditional geometric optics, a geometric lens focuses light by changing the refraction direction of incident light.

[0003] Limited by the refractive index of the lens material, geometric lenses often require a large space to achieve focusing. In addition, in some scenarios, wavelength division multiplexing needs to be achieved, that is, using the same lens to focus light of different wavelengths. For example, in biophotonic imaging, in order to obtain high-contrast and high-resolution images, light sources of different wavelengths are often used to irradiate biological samples, so as to observe the morphology and performance of sample tissues under the irradiation of light sources of different wavelengths. When wavelength division multiplexing is achieved based on geometric lenses, it is necessary to adapt the focusing depth of different wavelengths, and often requires a complex and bulky lens group.

[0004] Therefore, when wavelength division multiplexing is achieved based on geometric lenses, the imaging system has the problem of being bulky. Summary of the Invention

[0005] This application provides a metalens, a method for determining the structural parameters of a metalens, a device, an apparatus, an optical imaging device, a storage medium, and a program product, so as to solve the problem that the imaging system is bulky when wavelength division multiplexing is achieved based on geometric lenses in related technologies.

[0006] In a first aspect, this application provides a metalens, which includes a plurality of regions; any region includes a plurality of nano fins;

[0007] Wherein, at least some regions are used for focusing incident light of different wavelengths.

[0008] In a possible implementation, the plurality of regions are divided into N groups, each group includes at least one region, and the at least one region in each group is used for focusing incident light of the same wavelength; N is the number of different wavelengths to be focused by the metalens.

[0009] In a possible implementation, the number of regions in each group is two.

[0010] In a possible implementation, the two regions in each group are symmetrically arranged with respect to the center point of the metalens.

[0011] In a possible implementation, the region is a fan-shaped region, and the plurality of fan-shaped regions are formed by dividing based on a plurality of straight lines passing through the center of the metalens.

[0012] In a possible implementation, the areas of the respective sector regions of the metalens are the same.

[0013] In a possible implementation, the structural parameters of the multiple nano fins in the region are related to the wavelength of the incident light focused by the region.

[0014] In a possible implementation, the structural parameters include at least one of the following: size, rotation angle; the rotation angle is the included angle between the central axis corresponding to the long side of the nano fin and the horizontal direction.

[0015] In a possible implementation, the structural parameters include a rotation angle, and the rotation angles of the multiple nano fins included in the region are related to the wavelength of the incident light focused by the region and the target focal length.

[0016] In a possible implementation, the structural parameters include size; the sizes of the nano fins in the regions corresponding to incident lights of different wavelengths are different.

[0017] In a possible implementation, the size of the nano fins on the region is positively correlated with the wavelength of the incident light focused by the region.

[0018] In a possible implementation, the size includes length and width.

[0019] In a second aspect, the present application provides a method for determining the structural parameters of a metalens. The metalens includes multiple regions, and at least some of the regions are used to focus incident lights of different wavelengths. The method includes:

[0020] Determine the structural parameters of the multiple nano fins included in the region according to the wavelength of the incident light focused by the region.

[0021] In a possible implementation, the multiple regions are divided into N groups, each group includes at least one region, and the at least one region in each group is used to focus incident lights of the same wavelength; N is the number of different wavelengths to be focused by the metalens.

[0022] In a possible implementation, the number of regions in each group is two.

[0023] In a possible implementation, the two regions in each group are symmetrically arranged with respect to the center point of the metalens.

[0024] In a possible implementation, the region is a sector region, and the multiple sector regions are formed by dividing based on multiple straight lines passing through the center of the metalens.

[0025] In a possible implementation, the areas of the respective fan-shaped regions of the metalens are the same.

[0026] In a possible implementation, the structural parameters include at least one of the following: size, rotation angle; the rotation angle is the included angle between the central axis corresponding to the long side of the nanoscale fin and the horizontal direction.

[0027] In a possible implementation, the structural parameters include a rotation angle; according to the wavelength of the incident light used for focusing in the region, the structural parameters of the multiple nanoscale fins included in the region are determined, including:

[0028] According to the wavelength of the incident light used for focusing in the region and the target focal length, the rotation angles of the multiple nanoscale fins included in the region are determined.

[0029] In a possible implementation, according to the wavelength of the incident light used for focusing in the region and the target focal length, determining the rotation angles of the multiple nanoscale fins included in the region includes:

[0030] According to the wavelength of the incident light used for focusing in the region and the target focal length, the phase distribution of the region is determined;

[0031] According to the phase distribution of the region, the rotation angles of the respective nanoscale fins on the region are determined.

[0032] In a possible implementation, according to the phase distribution of the region, determining the rotation angles of the respective nanoscale fins on the region includes:

[0033] For any nanoscale fin, according to the position of the nanoscale fin and the phase distribution of the region, the rotation angle of the nanoscale fin is determined.

[0034] In a possible implementation, according to the position of the nanoscale fin and the phase distribution of the region, determining the rotation angle of the nanoscale fin includes:

[0035] According to the position of the nanoscale fin and the phase distribution of the region, the target phase at the position of the nanoscale fin is determined; the target phase represents the phase modulation value caused by the nanoscale fin.

[0036] According to the target phase at the position of the nanoscale fin, the rotation angle of the nanoscale fin is determined.

[0037] In a possible implementation, according to the target phase at the position of the nanoscale fin, determining the rotation angle of the nanoscale fin includes:

[0038] According to the target phase and the corresponding relationship between the target phase and the rotation angle, the rotation angle of the nanoscale fin is determined.

[0039] In a possible implementation, the rotation angle of the nano fin is one half or negative one half of the target phase at the position where the nano fin is located; the rotation angle of the nano fin is related to the type of circularly polarized light of the incident light.

[0040] In a possible implementation, determining the phase distribution of the region according to the wavelength of the incident light used for focusing in the region and the target focal length includes:

[0041] Based on the wavefront phase formula corresponding to the region, determining the phase distribution of the region according to the wavelength of the incident light used for focusing in the region and the target focal length; wherein, the wavefront phase formulas corresponding to each region are different.

[0042] In a possible implementation, the structural parameters include dimensions; the dimensions of the nano fins in the regions corresponding to incident lights of different wavelengths are different.

[0043] In a possible implementation, the dimensions of the nano fins on the region are positively correlated with the wavelength of the incident light used for focusing in the region.

[0044] In a possible implementation, the dimensions include length and width.

[0045] In a third aspect, the present application provides a device for determining structural parameters of a metalens. The metalens includes multiple regions, and at least some of the regions are used for focusing incident lights of different wavelengths; the device includes:

[0046] A determination module, configured to determine the structural parameters of multiple nano fins included in the region according to the wavelength of the incident light used for focusing in the region.

[0047] In a fourth aspect, the present application provides an optical imaging device, including the metalens according to any one of the first aspect.

[0048] In a fifth aspect, the present application provides a device for determining structural parameters of a metalens, including: a processor and a memory. Code is stored in the memory, and the processor runs the code stored in the memory to execute the method according to any one of the second aspect.

[0049] In a sixth aspect, the present application provides a computer-readable storage medium, in which computer-executable instructions are stored. When the computer-executable instructions are executed by a processor, they are used to implement the method according to any one of the second aspect.

[0050] In a seventh aspect, the present application provides a computer program product, including a computer program. When the computer program is executed by a processor, it implements the method according to any one of the second aspect.

[0051] The present application provides a metalens, a method, an apparatus, a device, an optical imaging device, a storage medium, and a program product for determining the structural parameters of the metalens. The metalens includes multiple regions; any one of the regions includes multiple nano fins; wherein, at least some of the regions are used for focusing incident light of different wavelengths. Since the metalens is divided into multiple regions, each region can form a metalens that focuses incident light of different wavelengths, thereby realizing wavelength division multiplexing. Compared with realizing wavelength division multiplexing by using a traditional geometric optical lens, the metalens of the present application has the advantages of smaller volume and higher integration. Description of the Drawings

[0052] The drawings herein are incorporated into the specification and form a part of this specification, showing embodiments consistent with the present application, and are used together with the specification to explain the principles of the present application.

[0053] Figure 1 It is a schematic structural diagram of a traditional optical lens;

[0054] Figure 2 It is a schematic structural diagram of a metalens for realizing wavelength division multiplexing provided by an embodiment of the present application;

[0055] Figure 3 It is a flowchart of a method for determining the structural parameters of a metalens provided by an embodiment of the present application;

[0056] Figure 4 It is a schematic structural diagram of a P-B phase adjustment unit provided by an embodiment of the present application;

[0057] Figure 5 It is the additional phase applied to incident light by different regions of a wavelength division multiplexing metalens provided by an embodiment of the present application;

[0058] Figure 6 It is a schematic diagram of the phase of the outgoing light of circularly polarized incident light under the action of nano fins provided by an embodiment of the present application;

[0059] Figure 7 It is a schematic diagram of the conversion efficiency of nano fins for circularly polarized incident light provided by an embodiment of the present application;

[0060] Figure 8 It is a schematic diagram of the focusing of 650-nanometer incident light by a metalens in the YOZ plane provided by an embodiment of the present application;

[0061] Figure 9 It is a schematic diagram of the focusing of 850-nanometer incident light by a metalens in the XOZ plane provided by an embodiment of the present application;

[0062] Figure 10 It is a schematic diagram of a device for determining the structural parameters of a metalens provided by an embodiment of the present application;

[0063] Figure 11 Schematic diagram of a device for determining the structural parameters of a metalens provided in an embodiment of the present application.

[0064] Through the above-mentioned drawings, specific embodiments of the present application have been shown, and more detailed descriptions will be given hereinafter. These drawings and textual descriptions are not intended to limit the scope of the concept of the present application in any way, but to illustrate the concept of the present application to those skilled in the art by referring to specific embodiments. Detailed implementation manners

[0065] Here, exemplary embodiments will be described in detail, and examples thereof are shown in the drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The implementation manners described in the following exemplary embodiments do not represent all implementation manners consistent with the present application. On the contrary, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0066] In traditional geometric optics, a geometric lens focuses light by changing the refraction direction of incident light. Limited by the refractive index of the geometric lens material, a relatively large space is often required for the optical lens to achieve the purpose of focusing. This will lead to a series of problems such as a large volume and low integration degree in an imaging system based on geometric lenses, thus restricting the applicability of geometric optical lenses in portable devices or wearable devices.

[0067] Figure 1 Schematic diagram of the structure of a traditional optical lens, as Figure 1 shown, the lens group of this optical lens includes a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, and a sixth lens L6 arranged coaxially in sequence from the object side to the image side along the optical axis (i.e., the principal optical axis) of the optical lens.

[0068] The lenses in the above-mentioned lens group are easy to process. However, since the focusing imaging is realized based on geometric optical lenses, the size of this lens reaches the centimeter level, having the disadvantages of a huge volume and being difficult to integrate, and it cannot achieve wavelength-division multiplexing focusing.

[0069] Currently, it is often necessary to use a lens module with a large volume to achieve ideal focusing imaging. Therefore, it is difficult to integrate it into an imaging system with limited space, which goes against the original intention of intelligent portable devices.

[0070] Based on the above problems, the concept of metasurface lens emerged as the times require. Different from geometric lenses, metasurface lenses use micro-nano scale components to precisely process various elements of electromagnetic waves, such as amplitude, phase, polarization direction, propagation direction, etc., on the nano scale. Therefore, they have the advantages of being extremely light and thin, with a volume that can almost be ignored, etc., making it convenient to achieve a highly compact and integrated imaging system within a limited volume, and are expected to replace the huge and bulky geometric optical lens groups in traditional optical systems.

[0071] That is to say, different from traditional geometric optical lenses that use the change of refractive index surface distribution to manipulate incident light, metasurface lenses often regulate parameters such as the phase and amplitude of incident light based on sub-wavelength artificial structural units to achieve various functions similar to geometric optical lenses, such as focusing imaging. Therefore, they have an ultra-light and ultra-thin planar structure.

[0072] However, for the practical application of metasurface lenses, it is necessary to research and design metasurface lens elements suitable for various different application scenarios. Currently, according to different actual application scenarios, metasurface lenses can be designed into various types such as dual-focus lenses, zoom lenses, multi-layer metasurface lens groups, etc.

[0073] Limited by the lack of basic research, previously, the research on metasurface lenses was basically based on a single wavelength, and the research on wavelength division multiplexing of metasurface lenses was relatively lacking. Wavelength division multiplexing refers to using the same metasurface lens to image light sources of different wavelengths, which can expand the application scope and field of metasurface lenses.

[0074] For example, in the field of biophoton imaging, in order to obtain high-contrast imaging, it is often necessary to irradiate biological samples with light sources of different wavelengths, so as to observe the morphology and performance of the sample tissue under the irradiation of light sources of different wavelengths. However, the optimal focusing depths of light sources of different wavelengths are often inconsistent. To use geometric optical lenses to adapt to the focusing depths of different wavelengths, a complex and bulky lens group is often required, which not only conflicts with the small volume required by biophoton imaging instruments, but also reduces the portability of detection equipment, contrary to the general trend of future optical imaging equipment towards being lightweight and intelligent.

[0075] Based on this, the present application proposes a metasurface lens capable of wavelength division multiplexing. The metasurface lens is divided into multiple regions, and multiple nano fins arranged in each region form a sub-metasurface lens. Through multiple sub-metasurface lenses, two or more wavelengths can be simultaneously manipulated to image at different focusing depths, thereby obtaining a metasurface lens capable of wavelength division multiplexing. Compared with the lens group that realizes wavelength division multiplexing based on geometric lenses, the metasurface lens of the present application has the advantages of small volume and high integration.

[0076] The following uses specific embodiments to elaborate in detail on the technical solution of the present application and how the technical solution of the present application solves the above technical problems. The following several specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0077] Figure 2 FIG. is a schematic structural diagram of a superlens for implementing wavelength division multiplexing provided by an embodiment of the present application. As Figure 2 shown, the superlens provided by the present application includes multiple regions; any region includes multiple nano fins;

[0078] Among them, at least some regions are used to focus incident light of different wavelengths.

[0079] In order to implement wavelength division multiplexing, that is, the same superlens can image incident light of different wavelengths, the superlens can be divided into multiple regions.

[0080] In some embodiments, the structural parameters of the multiple nano fins in the region are related to the wavelength of the incident light focused by the region.

[0081] Each region corresponds to a sub-superlens. Multiple nano fins can be arranged on each sub-superlens, and the size of the nano fins on the sub-superlens can be determined according to the wavelength of the incident light to be focused by the sub-superlens.

[0082] Optionally, the superlens includes multiple regions. To implement wavelength division multiplexing, at least some regions are used to focus incident light of different wavelengths. Exemplarily, when the superlens is to implement wavelength division multiplexing for incident light of three wavelengths, then at least 3 regions are used to focus incident light of different wavelengths. In addition, there can also be some regions used to focus incident light of the same wavelength. For example, there are two regions used to focus incident light of the same wavelength.

[0083] The superlens provided by the present application includes multiple regions; any region includes multiple nano fins; among them, at least some regions are used to focus incident light of different wavelengths. Since the superlens is divided into multiple regions, each region can form a superlens for focusing incident light of different wavelengths, thereby implementing wavelength division multiplexing. Compared with implementing wavelength division multiplexing using traditional geometric optical lenses, the superlens of the present application has the advantages of smaller volume and higher integration.

[0084] In some embodiments, the multiple regions are divided into N groups, each group includes at least one region, and the at least one region in each group is used to focus incident light of the same wavelength; N is the number of different wavelengths to be focused by the superlens.

[0085] Multiple regions in the metalens can be divided into N groups, where each region in a group can focus incident light of the same wavelength. When the metalens needs to focus incident light of N different wavelengths, the multiple regions can be divided into N groups.

[0086] By having each region in a group focus incident light of the same wavelength, multiple focal spots can be formed on the metalens for the incident light of the same wavelength.

[0087] In some embodiments, the number of regions in each group is two. In some embodiments, the two regions in each group are symmetrically arranged with respect to the center point of the metalens.

[0088] The number of regions in each group can be two, and by symmetrically arranging the two regions with respect to the center point of the metalens, two focal spots that are symmetric in position can be obtained.

[0089] In some embodiments, the region is a fan-shaped region, and multiple fan-shaped regions are divided based on multiple straight lines passing through the center of the metalens. In some embodiments, the areas of the respective fan-shaped regions of the metalens are the same.

[0090] The metalens can be circular in shape, and the multiple regions divided can be fan-shaped regions, which are divided based on multiple straight lines passing through the center of the metalens.

[0091] Exemplarily, by two straight lines passing through the center of the metalens, the metalens can be divided into four fan-shaped regions; by three straight lines passing through the center of the metalens, the metalens can be divided into six fan-shaped regions.

[0092] Optionally, if the areas of the divided fan-shaped regions are the same, the metalens can achieve good imaging for incident light of different wavelengths.

[0093] As Figure 2 shown, the metalens is evenly divided into 4 fan-shaped regions for focusing incident light of two wavelengths.

[0094] In some embodiments, the structural parameters include at least one of the following: size, rotation angle; the rotation angle is the angle between the central axis corresponding to the long side of the nanoscale fin and the horizontal direction.

[0095] Optionally, the incident light can be circularly polarized light, and exemplarily, it can be left-handed circularly polarized light. When adjusting the rotation angle of the nanoscale fin, the adjustment of the output phase of the circularly polarized incident light can be achieved. Therefore, the structural parameters of the metalens that need to be determined include the rotation angle of the nanoscale fin.

[0096] In addition, in order to achieve the regulation of incident light of different wavelengths, the size of the nanoscale fin should be on the sub-wavelength scale.

[0097] In some embodiments, the structural parameter includes a rotation angle, and the rotation angles of the multiple nano fins included in the region are related to the wavelength of the incident light used for focusing in the region and the target focal length.

[0098] Optionally, the nano fin may be a rectangular unit structure, that is, the shape of the nano fin is rectangular, and the nano fin includes a long side and a short side. The rotation angle refers to the included angle between the central axis corresponding to the long side of the nano fin and the horizontal direction.

[0099] For a region, when determining the rotation angles of the respective nano fins in the region, it can be determined according to the wavelength of the incident light to be focused in the region and the target focal length. The target focal length here refers to the focal length at which it is desired to focus the incident light. Based on the wavelength of the incident light and the target focal length, the rotation angles of the respective nano fins in the corresponding region can be determined.

[0100] Exemplarily, when the first region of the metalens needs to process the incident light of the first wavelength and the second region needs to process the incident light of the second wavelength, the rotation angles of the respective nano fins in the first region are related to the first wavelength and the first target focal length at which it is desired to focus the incident light of the first wavelength; the rotation angles of the respective nano fins in the second region are related to the second wavelength and the second target focal length at which it is desired to focus the incident light of the second wavelength.

[0101] In some embodiments, the structural parameter includes a size; the sizes of the nano fins in the regions corresponding to incident lights of different wavelengths are different.

[0102] In some embodiments, the size includes a length and a width.

[0103] Exemplarily, when there are incident lights of two wavelengths, the size of the nano fins in the region corresponding to the incident light of the first wavelength is size 1, and the size of the nano fins in the region corresponding to the incident light of the second wavelength is size 2, then size 1 and size 2 are different. That is, the length of the nano fins in the region corresponding to the incident light of the first wavelength is different from the length of the nano fins in the region corresponding to the incident light of the second wavelength, and the width of the nano fins in the region corresponding to the incident light of the first wavelength and the width of the nano fins in the region corresponding to the incident light of the second wavelength are different.

[0104] In some embodiments, the size of the nano fins on the region is positively correlated with the wavelength of the incident light used for focusing in the region.

[0105] The size of the nano fins is related to the wavelength of the focused incident light. When the wavelength of the incident light is longer, the size of the nano fins is larger.

[0106] Optionally, when the first wavelength is less than the second wavelength, the length of the nanoscale fins that focus the incident light of the first wavelength is less than the length of the nanoscale fins that focus the incident light of the second wavelength; and, the width of the nanoscale fins that focus the incident light of the first wavelength is less than the width of the nanoscale fins that focus the incident light of the second wavelength.

[0107] Figure 3 The flowchart shows a method for determining the structural parameters of a metalens provided by an embodiment of the present application. The method of this embodiment can be executed by a device for determining the structural parameters of a metalens and can be implemented in a manner combining hardware, software, or both. As Figure 3 shown, the method may include:

[0108] Step S301: Determine the structural parameters of the multiple nanoscale fins included in the region according to the wavelength of the incident light focused by the region.

[0109] Among them, the metalens includes multiple regions, and at least some regions are used to focus incident light of different wavelengths.

[0110] To achieve wavelength division multiplexing, that is, the same metalens can image incident light of different wavelengths, the metalens can be divided into multiple regions, each region corresponding to a sub-metalens, and the size of the nanoscale fins on the sub-metalens can be determined according to the wavelength of the incident light to be focused by the sub-metalens.

[0111] Optionally, the metalens includes multiple regions. To achieve wavelength division multiplexing, at least some regions are used to focus incident light of different wavelengths. Exemplarily, when the metalens is to achieve wavelength division multiplexing for incident light of three wavelengths, then at least 3 regions are used to focus incident light of different wavelengths. In addition, there may also be some regions used to focus incident light of the same wavelength. For example, there are two regions used to focus incident light of the same wavelength.

[0112] When there are two incident lights to be focused by the metalens, the metalens can be divided into four regions, and every two regions focus on the same incident light. The metalens provided by the present application can perform wavelength division multiplexing on two different wavelengths of incident light. By dividing the metalens into four regions, the four sub-metalenses designed for the two wavelengths are respectively arranged in these four regions. In this way, through the phase change effect of these four sub-metalenses, the incident lights of the two wavelengths are respectively focused on focal points with different focal lengths and non-overlapping. In this way, incident lights of different wavelengths will be simultaneously focused on detectors at different depths. This metalens has important application value in spectroscopic imaging.

[0113] The present application provides a method for determining the structural parameters of a metalens. The metalens includes multiple regions, and at least some of the regions are used to focus incident light of different wavelengths. The method includes: determining the structural parameters of multiple nanoscale fins included in the region according to the wavelength of the incident light focused by the region. Since the metalens is divided into multiple regions, and based on the difference in the wavelengths of the incident light focused by the regions, the structural parameters of the nanoscale fins in the regions are determined, thereby realizing wavelength division multiplexing of the metalens. Compared with realizing wavelength division multiplexing using traditional geometric lenses, the metalens of the present application has the advantages of a smaller volume and a higher integration level.

[0114] In some embodiments, the multiple regions are divided into N groups, each group includes at least one region, and the at least one region in each group is used to focus incident light of the same wavelength; N is the number of different wavelengths that the metalens is to focus.

[0115] The multiple regions in the metalens can be divided into N groups, where each region in each group can focus incident light of the same wavelength. When the metalens needs to focus N kinds of incident light of different wavelengths, the multiple regions can be divided into N groups.

[0116] By focusing the incident light of the same wavelength through the regions in a group, multiple focal spots can be formed on the metalens for the incident light of the same wavelength.

[0117] In some embodiments, the number of regions in each group is two. In some embodiments, the two regions in each group are symmetrically arranged with respect to the center point of the metalens.

[0118] The number of regions in each group can be two, and by symmetrically arranging the two regions with respect to the center point of the metalens, two focal spots that are symmetric in position can be obtained.

[0119] In some embodiments, the region is a fan-shaped region, and the multiple fan-shaped regions are divided based on multiple straight lines passing through the center of the metalens. In some embodiments, the areas of the respective fan-shaped regions of the metalens are the same.

[0120] The metalens can be circular in shape, then the multiple regions divided can be fan-shaped regions, and the fan-shaped regions are divided based on multiple straight lines passing through the center of the metalens.

[0121] Exemplarily, by two straight lines passing through the center of the metalens, the metalens can be divided into four fan-shaped regions; by three straight lines passing through the center of the metalens, the metalens can be divided into six fan-shaped regions.

[0122] Optionally, if the areas of the divided fan-shaped regions are the same, the metalens can image incident light of different wavelengths well.

[0123] like Figure 2 As shown, the metalens is evenly divided into four sector-shaped areas for focusing incident light of two wavelengths.

[0124] In some embodiments, the structural parameter includes at least one of the following: size, rotation angle; the rotation angle is the angle between the central axis corresponding to the long side of the nanofin and the horizontal direction.

[0125] Optionally, the incident light can be circularly polarized light, exemplarily, left-handed circularly polarized light. Adjusting the rotation angle of the nanofins can adjust the output phase of the circularly polarized incident light. Therefore, the structural parameters of the metalens that need to be determined include the rotation angle of the nanofins.

[0126] In addition, in order to achieve regulation of incident light of different wavelengths, the size of the nanofins should be at the subwavelength level.

[0127] In some embodiments, the size includes length and width. That is, when the wavelengths of incident light to be processed by the two regions are different, the lengths and widths of the nanofins corresponding to the two regions are also different.

[0128] like Figure 2 As shown, the superlens is composed of two nanofins of different sizes. The nanofins in the left and right fan-shaped areas have the same size, and the nanofins in the upper and lower fan-shaped areas have the same size.

[0129] By determining the rotation angle and size of each nanofin in each area, the incident light of the corresponding wavelength can be accurately focused.

[0130] In some embodiments, the structural parameters include a rotation angle; and determining the structural parameters of the plurality of nanofins included in the region according to a wavelength of incident light used to focus the region comprises:

[0131] The rotation angles of the plurality of nanofins included in the region are determined according to the wavelength of the incident light used to focus the region and the target focal length.

[0132] Optionally, the nanofin may be a rectangular unit structure, that is, the nanofin is rectangular in shape and includes a long side and a short side. The rotation angle refers to the angle between the central axis corresponding to the long side of the nanofin and the horizontal direction.

[0133] Figure 4 This is a structural schematic diagram of a PB phase adjustment unit provided in an embodiment of the present application. The upper rectangular unit structure in the figure is the nanofin, and the lower layer is the substrate. The substrate and the nanofin can form a PB phase adjustment unit. One area contains multiple phase adjustment units to achieve focusing of the incident light. Figure 4The rotation angle of the nano-fin is shown, which is the angle between the central axis corresponding to the long side of the nano-fin and the horizontal direction. The length, width, and height of the nano-fin are denoted as L, W, and H respectively, the period is Px * Py, and the rotation angle is α.

[0134] For a region, when determining the rotation angles of the respective nano-fins in the region, it can be determined according to the wavelength of the incident light to be focused in the region and the target focal length. Here, the target focal length refers to the focal length at which it is desired to focus the incident light. By based on the wavelength of the incident light and the target focal length, the rotation angles of the respective nano-fins in the corresponding region can be determined.

[0135] Exemplarily, when the first region of the superlens needs to process the incident light of the first wavelength and the second region needs to process the incident light of the second wavelength, then the rotation angles of the respective nano-fins in the first region are related to the first wavelength and the first target focal length at which it is desired to focus the incident light of the first wavelength; the rotation angles of the respective nano-fins in the second region are related to the second wavelength and the second target focal length at which it is desired to focus the incident light of the second wavelength.

[0136] By based on the wavelength of the incident light and the target focal length, it is possible to accurately determine the rotation angles of the nano-fins in different regions.

[0137] In some embodiments, determining the rotation angles of the plurality of nano-fins included in the region according to the wavelength of the incident light used for focusing in the region and the target focal length includes:

[0138] Determining the phase distribution of the region according to the wavelength of the incident light used for focusing in the region and the target focal length;

[0139] Determining the rotation angles of the respective nano-fins on the region according to the phase distribution of the region.

[0140] When determining the rotation angles of the respective nano-fins included in a certain region, the phase distribution corresponding to the region can be determined first. Among them, the phase distribution is used to characterize the target phases corresponding to different positions in the region of the superlens.

[0141] Optionally, the phase distributions of the respective regions in the superlens can be determined until the phase distributions of all regions are determined, so that the rotation angles of the respective nano-fins in the superlens can be determined based on the phase distributions of the respective regions.

[0142] In some embodiments, determining the phase distribution of the region according to the wavelength of the incident light used for focusing in the region and the target focal length includes:

[0143] Based on the wavefront phase formula corresponding to the region, determining the phase distribution of the region according to the wavelength of the incident light used for focusing in the region and the target focal length; among them, the wavefront phase formulas corresponding to the respective regions are different.

[0144] When determining the phase distribution of a region, it can be determined according to the wavefront phase formula corresponding to the region. As Figure 2 shown, when there are four fan-shaped regions in the metalens, each region corresponds to a wavefront phase formula. Based on the wavefront phase formula corresponding to the region, as well as the wavelength of the incident light focused by the region and the target focal length, the phase distribution is determined.

[0145] Optionally, when the metalens needs to focus incident light of two wavelengths, in order to achieve the design goal of off-axis focusing achromatism, the wavefront phase formulas for the two incident lights are respectively:

[0146]

[0147] In the above four formulas, λ1 and λ2 respectively represent the wavelengths of the two incident lights, and f1 and f2 respectively represent the target focal lengths of the two incident lights. Exemplarily, the wavelengths of the two incident lights are 650 nanometers and 850 nanometers respectively, and the values of f1 and f2 are set to 20 μm and 40 μm respectively. r is the radius of the metalens, equal to 25 μm, and (x, y) represents the position of the nanoscale fins. In the above four formulas, by changing the center position of the metalens phase wavefront formula, spatial and wavelength multiplexing of the metalens can be achieved.

[0148] Optionally, after the two incident lights with different wavelengths pass through the metalens, due to the different equivalent refractive indices of the metalens, different phases are given to different incident lights, so that the two incident lights can be focused at different positions and different focal lengths.

[0149] It should be noted that when constructing a metalens for wavelength division multiplexing of two wavelengths of incident light, the metalens can be equally divided into four fan-shaped areas with the same area to achieve focusing, that is, different wavefront phase formulas are distributed in different fan-shaped areas of the metalens. From the perspective of a spatial wavelength multiplexing metalens, it will give different additional phases to the incident light irradiating different areas.

[0150] Figure 5 The additional phases applied by different regions of a wavelength division multiplexing metalens provided by an embodiment of the present application to the incident light can be seen. There is a sub-metalens in each of the four fan-shaped partitions. The four sub-metalenses will respectively apply additional phases to different wavelength incident lights irradiating on themselves and achieve focusing respectively.

[0151] By using the wavefront phase formula corresponding to each region to determine the phase distribution of the region, and thus determine the rotation angle of each nanoscale fin in the region, the accuracy of the determined rotation angle can be improved.

[0152] In some embodiments, determining the rotation angle of each nanoscale fin on the region according to the phase distribution of the region includes:

[0153] For any nanoscale fin, determine the rotation angle of the nanoscale fin according to the position where the nanoscale fin is located and the phase distribution of the region.

[0154] After determining the phase distribution in a region, the rotation angles of the respective nanoscale fins in that region can be determined. Among them, the rotation angles of the respective nanoscale fins in a region are different, and the rotation angle of a nanoscale fin is related to the position where the nanoscale fin is located.

[0155] In some embodiments, determining the rotation angle of the nanoscale fin according to the position where the nanoscale fin is located and the phase distribution of the region includes:

[0156] Determine the target phase at the position where the nanoscale fin is located according to the position where the nanoscale fin is located and the phase distribution of the region; the target phase represents the phase modulation value caused by the nanoscale fin;

[0157] Determine the rotation angle of the nanoscale fin according to the target phase at the position where the nanoscale fin is located.

[0158] When determining the rotation angle of a nanoscale fin, it can be determined according to the position where the nanoscale fin is located and the phase distribution of the region. Specifically, the target phase at the position where the nanoscale fin is located can be determined according to the position where the nanoscale fin is located and the phase distribution of the region, that is, the phase modulation value caused by the nanoscale fin. After determining the target phase, the rotation angle of the nanoscale fin can be determined.

[0159] Specifically, for each nanoscale fin in a region, the target phase at the position where each nanoscale fin is located can be calculated, so as to determine the rotation angles of the respective nanoscale fins.

[0160] In some embodiments, determining the rotation angle of the nanoscale fin according to the target phase at the position where the nanoscale fin is located includes:

[0161] Determine the rotation angle of the nanoscale fin according to the target phase and the corresponding relationship between the target phase and the rotation angle.

[0162] After determining the target phase at the position where the nanoscale fin is located, the rotation angle of the nanoscale fin is determined according to the corresponding relationship between the target phase and the rotation angle.

[0163] Among them, there is a corresponding relationship between the target phase and the rotation angle. When the target phase is known, the rotation angle can be accurately obtained.

[0164] By determining the corresponding relationship between the target phase and the rotation angle, the rotation angle of the nanoscale fin can be accurately calculated.

[0165] In some embodiments, the rotation angle of the nanoscale fin is one-half or negative one-half of the target phase at the position where the nanoscale fin is located; the rotation angle of the nanoscale fin is related to the type of circularly polarized light of the incident light.

[0166] Optionally, according to whether the incident light is right-handed circularly polarized light or left-handed circularly polarized light, the rotation angle of the nanoscale fin is one-half or negative one-half of the target phase at the position where the nanoscale fin is located.

[0167] Metasurfaces are generally constructed using dielectric materials, and dielectric materials use the theory of the equivalent refractive index of the medium to control the phase.

[0168] There are mainly two ways to control the phase. One is the transmission phase type control method, and the other is the geometric phase type control method, also known as the P-B (Pancharatnam-Berry) phase. This patent will use P-B phase manipulation to achieve the design goal of the metasurface. The so-called PB phase means that on the premise that the incident light is circularly polarized light, phase control is achieved by adjusting the rotation angle of nanoscale fins with the same size.

[0169] For a nanoscale fin, it can be a rectangular structure, and the central axes corresponding to its long side and short side can be regarded as the fast axis and slow axis of the birefringent element. The P-B phase modulation effect of the nanoscale fin (where the angle between the fast axis and the horizontal direction is α) on the light field can be represented by the Jones matrix as:

[0170]

[0171] where E t represents the electromagnetic scattering response of the nanoscale fin under circularly polarized incident light, and respectively represent the electric field scattering components of the nanoscale fin in the x-axis direction and the y-axis direction, M ani represents the scattering matrix of the nanoscale fin, and represent the co-polarized transmission coefficients of the nanoscale fin under the excitation of linearly polarized electromagnetic waves in the x-axis and y-axis directions without rotation, α represents the rotation angle of the nanoscale fin, [1, i] represents the unnormalized Jones matrix of left-handed circularly polarized light, and [1, -i] represents the unnormalized Jones matrix of right-handed circularly polarized light. From the mathematical relationship shown by the above formula, it can be seen that under the action of circularly polarized incident light, through the P-B phase, rotating the nanoscale fin by an angle α along the z-axis can generate a phase modulation of ±2α on the cross-polarized transmission phase, and the above modulation effect is independent of the wavelength. That is to say, for right-handed or left-handed circularly polarized incident light of different wavelengths, the phase difference modulation of ±2α remains constant.

[0172] That is, when the rotation angle of the nano-fin is α, the target phase generated by the nano-fin is 2α. Therefore, after determining the target phase of the position where the nano-fin is located, the rotation angle can be determined to be one-half or negative one-half of the target phase according to whether the incident light is right-handed or left-handed circularly polarized light.

[0173] Through the above method, the rotation angles of the nano-fins on the metalens can be determined. In addition, the sizes of the nano-fins in different regions also need to be determined.

[0174] In some embodiments, the structural parameters include size; the sizes of the nano-fins in the regions corresponding to incident light of different wavelengths are different.

[0175] The size of the nano-fin may include length and width. Exemplarily, when there are two wavelengths of incident light, the size of the nano-fin in the region corresponding to the incident light of the first wavelength is size 1, and the size of the nano-fin in the region corresponding to the incident light of the second wavelength is size 2, then size 1 and size 2 are different. That is, the length of the nano-fin in the region corresponding to the incident light of the first wavelength is different from the length of the nano-fin in the region corresponding to the incident light of the second wavelength, and the width of the nano-fin in the region corresponding to the incident light of the first wavelength is different from the width of the nano-fin in the region corresponding to the incident light of the second wavelength.

[0176] In some embodiments, the size of the nano-fin on the region is positively correlated with the wavelength of the incident light focused by the region.

[0177] The size of the nano-fin is related to the wavelength of the focused incident light. When the wavelength of the incident light is longer, the size of the nano-fin is larger.

[0178] Optionally, when the first wavelength is less than the second wavelength, the length of the nano-fin focusing the incident light of the first wavelength is less than the length of the nano-fin focusing the incident light of the second wavelength; and the width of the nano-fin focusing the incident light of the first wavelength is less than the width of the nano-fin focusing the incident light of the second wavelength.

[0179] Exemplarily, the first wavelength is 650 nm and the second wavelength is 850 nm. In order to achieve the regulation of the incident light of these two wavelengths, the size of the nano-fin should be in the sub-wavelength order. According to the actual order of magnitude of these two wavelengths and the difference between them, the lengths of the nano-fins corresponding to the incident light of 650 nm and 850 nm are set to 0.105 um and 0.18 um respectively, and the widths are set to 0.125 um and 0.225 um respectively.

[0180] Such as Figure 2As shown, when wavelength division multiplexing of incident light of two wavelengths is implemented, the sizes of the nano fins in the left and right regions are the same, and the sizes of the nano fins in the upper and lower regions are the same. This superlens is composed of nano fins of two different sizes.

[0181] In addition, the size of the nano fin also includes height and period. For the nano fins in different regions of the superlens, the height of the nano fins is the same and the period is the same. Here, the period refers to the repeating arrangement interval of the nano fins in space. Exemplarily, when the wavelengths of the two incident lights focused by the superlens are respectively: the first wavelength is 650 nanometers and the second wavelength is 850 nanometers, the height of the two types of nano fins is uniformly 0.3um, and the period of the two types of nano fins is uniformly 0.3um * 0.3um.

[0182] Optionally, the superlens further includes a substrate. To improve the conversion efficiency, the substrate material of the superlens is selected as low-refractive-index silica, while the material of the nano fins is selected as high-refractive-index single-crystalline silicon. Through the rotation angles and sizes of the nano fins designed for the two incident lights, the conversion efficiency of the two types of nano fins for circularly polarized incident light and the phase of the outgoing light can be obtained.

[0183] Figure 6 This is a schematic diagram of the outgoing phase of circularly polarized incident light under the action of nano fins provided by an embodiment of the present application; Figure 7 This is a schematic diagram of the conversion efficiency of nano fins for circularly polarized incident light provided by an embodiment of the present application. The incident light is left-handed circularly polarized light, and the outgoing light is right-handed circularly polarized light. Refer to Figure 6 and Figure 7 , which show the phases and conversion efficiencies of right-handed circularly polarized light corresponding to two different sizes of nano fins. Among them, within the angular range of 0 - 180 degrees, the directions of the two types of nano fins are rotated to obtain the phase and conversion efficiency of the outgoing light. Here, different dashed lines respectively represent two incident lights with wavelengths of 650nm and 850nm.

[0184] Among them, different dashed lines respectively represent incident lights of 650 nanometers and 850 nanometers. It can be seen that the phase differences of these two wavelengths can both cover (-pi, pi), and within the rotation range of 0 - 180 degrees, the phase difference is always stable, which indicates that the lattice constant of 0.3um is appropriate. Because the prerequisite condition that resonance coupling cannot occur between the nano fins in the designed superlens needs to be satisfied. At the same time, the conversion efficiency from left-handed circularly polarized light to right-handed circularly polarized light has been maintained above 0.6. According to the circular polarization conversion efficiency and the outgoing phase, these two types of nano fins can be used to design a superlens based on P - B phase manipulation of the wavefront.

[0185] In summary, in order to achieve Figure 2The metalens shown imparts different phase differences to two incident light wavelengths. By combining the PB phase and rotating the orientation of the two nanofins of different sizes, the distribution, rotation direction, and size of the nanofins on the metalens are obtained for two different incident light wavelengths of 650 nanometers and 850 nanometers, respectively.

[0186] After designing the spatial wavelength multiplexing metalens based on the above method, the two light sources can be set to left-handed circularly polarized light with wavelengths of 650 nanometers and 850 nanometers, respectively, to observe the focusing effect. Figure 8 This is a schematic diagram of a metalens provided in an embodiment of the present application focusing 650 nm incident light on the YOZ plane. Figure 9 Schematic diagram of a metalens provided in an embodiment of the present application focusing 850 nm incident light in the XOZ plane, which are schematic diagrams of the focusing of the incident left-handed circularly polarized light in the YOZ plane and the XOZ plane after passing through the metalens.

[0187] like Figure 8 As shown, it can be seen on the YOZ plane that after the left-handed circularly polarized incident light with a wavelength of 650 nanometers passes through the metalens, two focal spots are obtained. The focal lengths of the two focal spots are both 20 μm, but they are located at ±15 μm (0.6r) away from the center of the metalens.

[0188] like Figure 9 As shown, on the XOZ plane, it can be seen that the left-handed circularly polarized incident light with a wavelength of 850 nanometers is also focused on two focal spots after passing through the metalens. Different from the incident light of 650 nanometers, their focusing focal length is 40 μm, but they are focused on ±15 μm above the center of the metalens.

[0189] In summary, after two left-handed circularly polarized incident lights of different wavelengths pass through their respective metalenses, they can both be focused, and the focal lengths and the distances of their offsets are in line with design expectations. Therefore, the spatial wavelength multiplexing metalenses proposed in this application can focus two left-handed circularly polarized incident lights of different wavelengths on focal spots with different focal lengths and offsets. The metalenses provided in this application can be used in situations where spatial wavelength division multiplexing imaging is required.

[0190] It should be noted that the above process is based on a metalens focusing two wavelengths of incident light. It is also possible to design a metalens that focuses three, four, or more wavelengths of incident light. This application does not limit the number of different wavelengths that the metalens can focus.

[0191] The present application also provides an optical imaging device including the metalens described in any of the above embodiments. For example, the optical imaging device can be a mobile phone, a smart wearable device, a microscope, laser processing equipment, a vehicle or aircraft equipped with an optical imaging system, or other equipment with optical imaging capabilities.

[0192] Figure 10 This is a schematic diagram of a device for determining the structural parameters of a metalens provided by an embodiment of the present application. The metalens includes multiple regions, and at least some of the regions are used to focus incident light of different wavelengths. The device 100 includes:

[0193] A determination module 1001, configured to determine the structural parameters of a plurality of nano fins included in the region according to the wavelength of the incident light focused by the region.

[0194] In some embodiments, the multiple regions are divided into N groups, each group includes at least one region, and the at least one region in each group is used to focus incident light of the same wavelength; N is the number of different wavelengths to be focused by the metalens.

[0195] In some embodiments, the number of regions in each group is two.

[0196] In some embodiments, the two regions in each group are symmetrically arranged with respect to the center point of the metalens.

[0197] In some embodiments, the region is a fan-shaped region, and the multiple fan-shaped regions are formed by dividing based on multiple straight lines passing through the center of the metalens.

[0198] In some embodiments, the areas of the respective fan-shaped regions of the metalens are the same.

[0199] In some embodiments, the structural parameters include at least one of the following: size, rotation angle; the rotation angle is the angle between the central axis corresponding to the long side of the nano fin and the horizontal direction.

[0200] In some embodiments, the structural parameters include a rotation angle; when the determination module 1001 determines the structural parameters of the multiple nano fins included in the region according to the wavelength of the incident light focused by the region, it is specifically configured to:

[0201] Determine the rotation angle of the multiple nano fins included in the region according to the wavelength of the incident light focused by the region and the target focal length.

[0202] In some embodiments, when the determination module 1001 determines the rotation angle of the multiple nano fins included in the region according to the wavelength of the incident light focused by the region and the target focal length, it is specifically configured to:

[0203] Determine the phase distribution of the region according to the wavelength of the incident light focused by the region and the target focal length;

[0204] Determine the rotation angle of each nano fin on the region according to the phase distribution of the region.

[0205] In some embodiments, when determining the rotation angle of each nanoscale fin on the region according to the phase distribution of the region, the determining module 1001 is specifically configured to:

[0206] For any nanoscale fin, determine the rotation angle of the nanoscale fin according to the position where the nanoscale fin is located and the phase distribution of the region.

[0207] In some embodiments, when determining the rotation angle of the nanoscale fin according to the position where the nanoscale fin is located and the phase distribution of the region, the determining module 1001 is specifically configured to:

[0208] Determine the target phase at the position where the nanoscale fin is located according to the position where the nanoscale fin is located and the phase distribution of the region; the target phase represents the phase modulation value caused by the nanoscale fin;

[0209] Determine the rotation angle of the nanoscale fin according to the target phase at the position where the nanoscale fin is located.

[0210] In some embodiments, when determining the rotation angle of the nanoscale fin according to the target phase at the position where the nanoscale fin is located, the determining module 1001 is specifically configured to:

[0211] Determine the rotation angle of the nanoscale fin according to the target phase and the corresponding relationship between the target phase and the rotation angle.

[0212] In some embodiments, the rotation angle of the nanoscale fin is one - half or negative one - half of the target phase at the position where the nanoscale fin is located; the rotation angle of the nanoscale fin is related to the circular polarization type of the incident light.

[0213] In some embodiments, when determining the phase distribution of the region according to the wavelength of the incident light used for focusing in the region and the target focal length, the determining module 1001 is specifically configured to:

[0214] Based on the wavefront phase formula corresponding to the region, determine the phase distribution of the region according to the wavelength of the incident light used for focusing in the region and the target focal length; wherein, the wavefront phase formulas corresponding to each region are different.

[0215] In some embodiments, the structural parameters include dimensions; the dimensions of the nanoscale fins in the regions corresponding to incident lights of different wavelengths are different.

[0216] In some embodiments, the dimensions of the nanoscale fins on the region are positively correlated with the wavelength of the incident light used for focusing in the region.

[0217] In some embodiments, the dimensions include length and width.

[0218] The device of this embodiment can be used to execute the method embodiment shown above. The implementation principle and technical effects are similar, and will not be elaborated here.

[0219] Figure 11 It is a schematic diagram of a device for determining the structural parameters of a metasurface provided by an embodiment of this application. As Figure 11 shown, the device 110 for determining the structural parameters of a metasurface provided by an embodiment of this application includes a processor 1101 and a memory 1102. Among them, the processor 1101 and the memory 1102 are connected through a bus 1103.

[0220] In the specific implementation process, the memory 1102 stores code, and the processor 1101 runs the code stored in the memory 1102 to execute the method of the above method embodiment.

[0221] The specific implementation process of the processor 1101 can be referred to the above method embodiment. The implementation principle and technical effects are similar, and will not be elaborated here in this embodiment.

[0222] In the above Figure 11 shown embodiment, it should be understood that the processor 1101 can be a central processing unit (English: Central Processing Unit, abbreviated: CPU), and can also be other general-purpose processors, digital signal processors (English: Digital Signal Processor, abbreviated: DSP), application specific integrated circuits (English: Application SpecificIntegrated Circuit, abbreviated: ASIC), etc. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor, etc. The steps of the method disclosed in combination with the invention can be directly embodied as being executed and completed by a hardware processor, or executed and completed by a combination of hardware and software modules in the processor.

[0223] The memory 1102 may include a high-speed RAM memory, and may also include a non-volatile storage NVM, such as at least one disk memory.

[0224] The bus 1103 can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. The bus can be divided into an address bus, a data bus, a control bus, etc. For the convenience of representation, the bus in the drawings of this application is not limited to only one bus or one type of bus.

[0225] An embodiment of the present application provides a computer-readable storage medium storing computer-executable instructions that, when executed by a processor, are used to implement the method of the above method embodiment.

[0226] The above computer-readable storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic memory, flash memory, a magnetic disk, or an optical disk. The readable storage medium can be any available medium accessible by a general-purpose or special-purpose computer.

[0227] An exemplary readable storage medium is coupled to the processor so that the processor can read information from and write information to the readable storage medium. Of course, the readable storage medium can also be a component of the processor. The processor and the readable storage medium can be located in an application specific integrated circuit (ASIC). Of course, the processor and the readable storage medium can also exist as discrete components in a device.

[0228] An embodiment of the present application provides a computer program product including a computer program that, when executed by a processor, implements the method provided in any of the above embodiments of the present application.

[0229] Those skilled in the art will readily conceive of other implementations of the present application after considering the specification and practicing the invention disclosed herein. The present application is intended to cover any variations, uses, or adaptations of the present application, which follow the general principles of the present application and include known common general knowledge or conventional technical means in the technical field not disclosed in the present application. The specification and the embodiments are only regarded as exemplary, and the true scope and spirit of the present application are pointed out by the following claims.

[0230] It should be understood that the present application is not limited to the exact structures described above and shown in the drawings, and various modifications and changes can be made without departing from its scope. The scope of the present application is only limited by the appended claims.

Claims

1. A metalens, characterized in that, The metalens includes a plurality of regions; any one of the regions includes a plurality of nano fins; wherein at least some of the regions are configured to focus incident light of different wavelengths.

2. The metalens according to claim 1, wherein The plurality of regions are divided into N groups, each group includes at least one region, and the at least one region in each group is configured to focus incident light of the same wavelength; N is the number of different wavelengths that the metalens is to focus.

3. The metalens according to claim 2, wherein The number of regions in each group is two.

4. The metalens according to claim 3, characterized in that The two regions in each group are symmetrically arranged with respect to the center point of the metalens.

5. The metalens according to claim 1, wherein The region is a fan-shaped region, and the plurality of fan-shaped regions are formed by dividing based on a plurality of straight lines passing through the center of the metalens.

6. The metalens according to claim 5, wherein The areas of the respective fan-shaped regions of the metalens are the same.

7. The metalens according to any one of claims 1-6, characterized in that, The structural parameters of the plurality of nano fins in the region are related to the wavelength of the incident light that the region is configured to focus.

8. The metalens according to claim 7, wherein The structural parameters include at least one of the following: size, rotation angle; the rotation angle is the angle between the central axis corresponding to the long side of the nano fin and the horizontal direction.

9. The metalens according to claim 8, wherein The structural parameters include a rotation angle, and the rotation angles of the plurality of nano fins included in the region are related to the wavelength of the incident light that the region is configured to focus and the target focal length.

10. The metalens according to claim 8, wherein, The structural parameters include size; the sizes of the nano fins in the regions corresponding to incident light of different wavelengths are different.

11. The metalens according to claim 10, wherein, The size of the nano fins on the region is positively correlated with the wavelength of the incident light that the region is configured to focus.

12. The metalens according to claim 10, wherein The size includes length and width.

13. A method for determining the structural parameters of a superlens, characterized in that The metalens includes a plurality of regions, and at least some of the regions are configured to focus incident light of different wavelengths; the method includes: Determining the structural parameters of the plurality of nano fins included in the region according to the wavelength of the incident light that the region is configured to focus.

14. The method according to claim 13, characterized in that, The plurality of regions are divided into N groups, each group includes at least one region, and the at least one region in each group is configured to focus incident light of the same wavelength; N is the number of different wavelengths that the metalens is to focus.

15. The method according to claim 14, wherein The number of regions in each group is two.

16. The method according to claim 15, wherein The two regions in each group are symmetrically arranged with respect to the center point of the metalens.

17. The method according to claim 13, wherein The region is a fan-shaped region, and the plurality of fan-shaped regions are formed by dividing based on a plurality of straight lines passing through the center of the metalens.

18. The method according to claim 17, wherein The areas of the respective fan-shaped regions of the metalens are the same.

19. The method according to claim 13, wherein The structural parameters include at least one of the following: size, rotation angle; the rotation angle is the angle between the central axis corresponding to the long side of the nano fin and the horizontal direction.

20. The method according to any one of claims 13-19, characterized in that, The structural parameters include a rotation angle; determining the structural parameters of the plurality of nano fins included in the region according to the wavelength of the incident light that the region is configured to focus includes: Determining the rotation angles of the plurality of nano fins included in the region according to the wavelength of the incident light that the region is configured to focus and the target focal length.

21. The method according to claim 20, wherein Determining the rotation angles of the plurality of nano fins included in the region according to the wavelength of the incident light that the region is configured to focus and the target focal length includes: Determining the phase distribution of the region according to the wavelength of the incident light that the region is configured to focus and the target focal length. Determining the rotation angles of the respective nano fins on the region according to the phase distribution of the region.

22. The method according to claim 21, wherein Determining the rotation angles of the respective nano fins on the region according to the phase distribution of the region includes: For any nano fin, determine the rotation angle of the nano fin according to the position of the nano fin and the phase distribution of the region.

23. The method according to claim 22, wherein Determining the rotation angle of the nano fin according to the position of the nano fin and the phase distribution of the region includes: Determine the target phase at the position of the nano fin according to the position of the nano fin and the phase distribution of the region; the target phase represents the phase modulation value caused by the nano fin. Determine the rotation angle of the nano fin according to the target phase at the position of the nano fin.

24. The method according to claim 23, wherein Determining the rotation angle of the nano fin according to the target phase at the position of the nano fin includes: Determine the rotation angle of the nano fin according to the target phase and the correspondence between the target phase and the rotation angle.

25. The method according to claim 24, wherein The rotation angle of the nano fin is one half or negative one half of the target phase at the position of the nano fin; the rotation angle of the nano fin is related to the circular polarization type of the incident light.

26. The method according to claim 21, wherein Determining the phase distribution of the region according to the wavelength of the incident light used for focusing in the region and the target focal length includes: Based on the wavefront phase formula corresponding to the region, determine the phase distribution of the region according to the wavelength of the incident light used for focusing in the region and the target focal length; wherein, the wavefront phase formulas corresponding to each region are different.

27. The method according to any one of claims 13-19, characterized in that, The structural parameters include dimensions; the dimensions of the nano fins in the regions corresponding to incident lights of different wavelengths are different.

28. The method according to claim 27, characterized in that, The dimensions of the nano fins on the region are positively correlated with the wavelength of the incident light used for focusing in the region.

29. The method according to claim 27, wherein The dimensions include length and width.

30. An apparatus for determining structural parameters of a metalens, characterized in that The superlens includes multiple regions, and at least some regions are used for focusing incident lights of different wavelengths; the device includes: A determination module, configured to determine the structural parameters of the multiple nano fins included in the region according to the wavelength of the incident light used for focusing in the region.

31. An optical imaging device, characterized in that, Includes the superlens according to any one of claims 1-12.

32. An apparatus for determining structural parameters of a metalens, characterized in that Includes: A processor and a memory, where code is stored in the memory, and the processor runs the code stored in the memory to execute the method according to any one of claims 13-29.

33. A computer-readable storage medium, characterized in that, Computer-executable instructions are stored in the computer-readable storage medium, and when the computer-executable instructions are executed by a processor, they are used to implement the method according to any one of claims 13-29.

34. A computer program product, characterized in that, Includes a computer program, which when executed by a processor, implements the method according to any one of claims 13-29.

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