Double-sided multilayer super lens

Abstract

The utility model provides a double-sided multi-layer super lens. The double-sided multi-layer super lens is provided with a substrate; at least two layers of structural surfaces are sequentially arranged on the first surface of the substrate in the direction perpendicular to the first surface; at least one layer of structural surface is sequentially arranged on the second surface of the substrate in the direction perpendicular to the second surface; wherein each layer of structural surface is provided with a micro-nano structure array. The double-sided multi-layer super lens provided by the utility model further improves the degree of freedom of design, and can be more suitable for broadband light modulation application scenarios.

Description

Technical Field

[0001] The present application relates to the field of lenses, and in particular to a double-sided multi-layer metalens. Background Art

[0002] In the field of lenses, the most widely used metalens is a single-sided single-layer metalens with only one structural surface on one side of the substrate. Although the single-sided single-layer metalens has a large degree of design freedom, the degree of design freedom it can provide is still slightly insufficient in some cases; moreover, due to the limitations of the phase coverage and dispersion curve control that the single-sided single-layer metalens can provide, the single-sided single-layer metalens is sometimes difficult to fully apply to wide-band light modulation application scenarios. Utility Model Content

[0003] One purpose of the present application is to propose a double-sided multi-layer metalens, which further improves the design freedom and is more suitable for wide-band light modulation application scenarios.

[0004] According to one aspect of an embodiment of the present application, a double-sided multilayer metalens is disclosed, characterized in that the double-sided multilayer metalens is provided with a substrate;

[0005] On the first surface of the substrate, at least two layers of structure surfaces are sequentially arranged in a direction perpendicular to the first surface;

[0006] On the second surface of the substrate, at least one layer of structure surfaces is sequentially arranged in a direction perpendicular to the second surface;

[0007] Each structural surface is provided with a micro-nano structure array.

[0008] In an exemplary embodiment of the present application, among all the structural surfaces provided on the same surface of the substrate, at least all the structural surfaces other than the uppermost layer are further provided with filling materials.

[0009] In an exemplary embodiment of the present application, the micro-nano structure included in at least one structural surface of the double-sided multi-layer metalens is spaced apart from the lower surface of the structural surface where the micro-nano structure is located.

[0010] In an exemplary embodiment of the present application, the micro-nano structure included in at least one structural surface of the double-sided multi-layer metalens is in contact with the lower surface of the structural surface where the micro-nano structure is located.

[0011] In an exemplary embodiment of the present application, the substrate and at least two layers of structured surfaces provided on the first surface together constitute a first superlens; the substrate and at least one layer of structured surfaces provided on the second surface together constitute a second superlens;

[0012] Wherein, the position deviation between the optical center of the first super lens and the optical center of the second super lens is less than a preset optical center position deviation threshold.

[0013] In an exemplary embodiment of the present application, the position deviation between the respective micro-nano structure arrays of all structure surfaces disposed on the same surface of the substrate is less than a preset micro-nano structure position deviation threshold.

[0014] In an exemplary embodiment of the present application, a filling material is provided on the uppermost structural surface of the first surface, and a first oxide layer is provided on the upper surface of the uppermost structural surface of the first surface;

[0015] A filling material is disposed on the uppermost structural surface of the second surface, and a second oxide layer is disposed on the upper surface of the uppermost structural surface of the second surface.

[0016] In an exemplary embodiment of the present application, on the same surface of the substrate, at least one layer of structure surface includes a micro-nano structure array entirely composed of positive micro-nano structures.

[0017] In an exemplary embodiment of the present application, on the same surface of the substrate, at least one layer of structure surface includes a micro-nano structure array entirely composed of negative micro-nano structures.

[0018] In an exemplary embodiment of the present application, on the same surface of the substrate, at least one layer of the structure surface includes a micro-nano structure array composed entirely of positive micro-nano structures, and at least one layer of the structure surface includes a micro-nano structure array composed entirely of negative micro-nano structures.

[0019] The double-sided multilayer metalens provided in the present application is provided with a substrate. On the first surface of the substrate, at least two layers of structural surfaces are sequentially arranged in a direction perpendicular to the first surface; on the second surface of the substrate, at least one layer of structural surfaces is sequentially arranged in a direction perpendicular to the second surface. Among them, each layer of structural surface is provided with a micro-nano structure array. After the structural surfaces are respectively arranged on the two side surfaces of the substrate, the obtained metalens can be regarded as two single-sided metalens that share the substrate. Therefore, compared with the single-sided single-layer metalens, the double-sided multilayer metalens further improves the design freedom. At the same time, for the multilayer structural surfaces arranged on the same surface of the substrate, the dispersion curves corresponding to the micro-nano structures in each layer of the structural surfaces can be separately regulated, thereby effectively enriching the nanostructure database, and thus facilitating the matching of the wide-band phase curve designed to meet the wide-band light modulation application scenario. Therefore, compared with the single-sided single-layer metalens, the double-sided multilayer metalens can provide a wider range of phase coverage and dispersion curve regulation, and is more suitable for wide-band light modulation application scenarios. From the above, it can be seen that compared with the single-sided single-layer metalens, the double-sided multi-layer metalens provided in the present application further improves the design freedom and is more suitable for wide-band light modulation application scenarios.

[0020] Other features and advantages of the present application will become apparent from the following detailed description, or may be learned in part by the practice of the present application.

[0021] It should be understood that the foregoing general description and the following detailed description are exemplary only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The above and other objects, features and advantages of the present application will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings.

[0023] Figure 1 A schematic diagram of the structure of a double-sided multi-layer metalens in one embodiment of the present application is shown.

[0024] Figure 2 A schematic diagram of the structure of a double-sided multi-layer metalens in one embodiment of the present application is shown.

[0025] Figure 3 A schematic diagram of the structure of a double-sided multi-layer metalens in one embodiment of the present application is shown.

[0026] Figure 4 A schematic diagram of the structure of a double-sided multi-layer metalens in one embodiment of the present application is shown.

[0027] Figure 5 A schematic diagram of the structure of a double-sided multi-layer metalens in one embodiment of the present application is shown.

[0028] Figure 6A schematic diagram of the structure of a double-sided multi-layer metalens in one embodiment of the present application is shown.

[0029] Figure 7 A top view of a first layer structure surface provided on a first surface in an embodiment of the present application is shown.

[0030] Figure 8 A top view of a second layer structure surface provided on a second surface in one embodiment of the present application is shown.

[0031] Fig. 9 A top view of a second layer structure surface provided on a first surface in one embodiment of the present application is shown.

[0032] Fig.10 A schematic diagram of the structure of a double-sided multi-layer metalens in one embodiment of the present application is shown.

[0033] Fig.11 A schematic diagram of the structure of a double-sided multi-layer metalens in one embodiment of the present application is shown.

[0034] Reference numerals:

[0035] 100-first oxide layer; 11-first structural surface on the first surface of the substrate; 111-micro-nano structures in the first structural surface on the first surface; 112-filling material in the first structural surface on the first surface; 113-positioning mark in the first structural surface on the first surface; 12-second structural surface on the first surface of the substrate; 121-micro-nano structures in the second structural surface on the first surface; 122-filling material in the second structural surface on the first surface; 123-positioning mark in the second structural surface on the first surface; 200-second oxide layer; 21-first structural surface on the second surface of the substrate; 211-micro-nano structures in the first structural surface on the second surface; 212-filling material in the first structural surface on the second surface; 213-positioning mark in the first structural surface on the second surface; 22-second structural surface on the second surface of the substrate; 221-micro-nano structures in the second structural surface on the second surface; 222-filling material in the second structural surface on the second surface; 30-substrate. DETAILED DESCRIPTION

[0036] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in a variety of forms and should not be construed as limited to the examples set forth herein; rather, these example embodiments are provided so that the description of the present application will be more comprehensive and complete and the concepts of the example embodiments will be fully conveyed to those skilled in the art. The accompanying drawings are only schematic illustrations of the present application and are not necessarily drawn to scale. The same reference numerals in the figures represent the same or similar parts, and thus their repeated description will be omitted.

[0037] In addition, the described features, structures or characteristics may be combined in one or more example embodiments in any suitable manner. In the following description, many specific details are provided to provide a full understanding of the example embodiments of the present application. However, those skilled in the art will appreciate that the technical solution of the present application may be practiced while omitting one or more of the specific details, or other methods, components, steps, etc. may be adopted. In other cases, known structures, methods, implementations or operations are not shown or described in detail to avoid obscuring the present application and making the various aspects of the present application obscure.

[0038] Some of the blocks shown in the accompanying drawings are functional entities that do not necessarily correspond to physically or logically independent entities. These functional entities can be implemented in software form, or in one or more hardware modules or integrated circuits, or in different networks and / or processing unit devices and / or microcontroller devices.

[0039] In order to overcome the above-mentioned defects of the single-sided single-layer metalens in the related art, the present application provides a double-sided multi-layer metalens, which further improves the design freedom and is more suitable for wide-band light modulation application scenarios.

[0040] Figure 1 FIG. 2 shows a schematic diagram of the structure of a double-sided multilayer metal lens in an embodiment of the present application. Figure 1 The double-sided multilayer metalens provided in the present application is provided with a substrate 30. The substrate 30 is selected from a material that is transparent in the working band. Specifically, when the target works in the visible light band or the near-infrared band, the substrate 30 can be selected from a quartz wafer; when the target works in the far-infrared band, the substrate 30 can be selected from a silicon wafer.

[0041] On the first surface of the substrate 30, at least two layers of structural surfaces are sequentially arranged along a direction perpendicular to the first surface. Also, on the second surface of the substrate 30, at least one layer of structural surfaces is sequentially arranged along a direction perpendicular to the second surface. Each layer of structural surfaces is provided with a micro-nano structure array.

[0042] Specific to Figure 1 In the figure, two layers of structural surfaces are arranged in sequence along the vertical direction on the first surface of the substrate 30: a first layer of structural surface 11 and a second layer of structural surface 12. On the second surface of the substrate 30, one layer of structural surface is arranged along the vertical direction: a first layer of structural surface 21. The first layer of structural surface 11 on the first surface is provided with an array of micro-nano structures 111, the second layer of structural surface 12 on the first surface is provided with an array of micro-nano structures 121, and the first layer of structural surface 21 on the second surface is provided with an array of micro-nano structures 211.

[0043] It should be noted that Figure 1The structure of the double-sided multilayer metal lens is only exemplarily shown, and should not limit the protection scope of the double-sided multilayer metal lens provided by the present application. Specifically, in the embodiment of the present application, only one layer of structure surface can be provided on the second surface of the substrate 30, or two or more layers of structure surface can be provided. Figure 2 FIG. 2 shows a schematic diagram of the structure of a double-sided multilayer metal lens in an embodiment of the present application. Figure 2 In one embodiment, two layers of structural surfaces are sequentially arranged on the second surface of the substrate 30 along the vertical direction: a first layer of structural surface 21 and a second layer of structural surface 22 .

[0044] Furthermore, in the embodiment of the present application, the number of layers of the structural surface provided on the first surface of the substrate 30 and the number of layers of the structural surface provided on the second surface of the substrate 30 may be equal or different. For example, two layers of structural surfaces are provided on the first surface and the second surface of the substrate 30; or, two layers of structural surfaces are provided on the first surface of the substrate 30 and three layers of structural surfaces are provided on the second surface.

[0045] In the embodiment of the present application, after the structural surfaces are respectively provided on the two side surfaces of the substrate 30, the obtained metalens can be regarded as two single-sided metalens that share the substrate 30. Therefore, compared with the single-sided single-layer metalens, the double-sided multi-layer metalens further improves the design freedom.

[0046] At the same time, for the multi-layer structure surface set on the same surface of the substrate 30, the dispersion curve corresponding to the micro-nano structure in each layer of the structure surface can be adjusted separately, thereby effectively enriching the nanostructure database, which is conducive to matching the wide-band phase curve designed to meet the wide-band light modulation application scenario. Therefore, compared with the single-sided single-layer metalens, the double-sided multi-layer metalens can provide a wider range of phase coverage and dispersion curve control, and is more suitable for wide-band light modulation application scenarios.

[0047] From the above, it can be seen that compared with the single-sided single-layer metalens, the double-sided multi-layer metalens provided in the present application further improves the design freedom and is more suitable for wide-band light modulation application scenarios.

[0048] It should be noted that, in the embodiment of the present application, for any structural surface, the surface of the substrate 30 where the structural surface is located is taken as the lowest horizontal plane relative to the structural surface, and then the structural surface is distinguished from the upper and lower parts on this basis. Specifically, if a structural surface is provided on the first surface of the substrate 30, the first surface of the substrate 30 is the lowest horizontal plane relative to the structural surface; similarly, if a structural surface is provided on the second surface of the substrate 30, the second surface of the substrate 30 is the lowest horizontal plane relative to the structural surface.

[0049] In one embodiment, among all the structural surfaces disposed on the same surface of the substrate 30 , at least all the structural surfaces other than the uppermost layer are further provided with filling materials.

[0050] In this embodiment, if only the micro-nano structure array and the filling material are taken as the objects of investigation, for all the structural surfaces provided on the same surface of the substrate 30, the structural surface of the top layer may be provided with both the micro-nano structure array and the filling material, or may be provided with only the micro-nano structure array, and the structural surfaces other than the top layer may be provided with both the micro-nano structure array and the filling material. When a filling material is provided in a certain structural surface, the filling material is regarded as a part of the structural surface.

[0051] Figure 3 FIG. 2 shows a schematic diagram of the structure of a double-sided multilayer metal lens in an embodiment of the present application. Figure 2 and Figure 3 If only the micro-nano structure array and the filling material are taken as the objects of investigation, for the first layer structure surface 11 and the second layer structure surface 12 arranged on the first surface of the substrate 30, the top second layer structure surface 12 can be provided with both the micro-nano structure 121 array and the filling material 122, or can be provided with only the micro-nano structure 121 array, and the first layer structure surface 11 can be provided with both the micro-nano structure 111 array and the filling material 112.

[0052] Similarly, if only the micro-nano structure array and the filling material are taken as the objects of investigation, for the first layer structure surface 21 and the second layer structure surface 22 arranged on the second surface of the substrate 30, the top second layer structure surface 22 can be provided with both the micro-nano structure 221 array and the filling material 222, or can be provided with only the micro-nano structure 221 array, and the first layer structure surface 21 can be provided with both the micro-nano structure 211 array and the filling material 212.

[0053] In this embodiment, by setting the filling material, the filled micro-nano structure array can be protected; and by selecting suitable materials, the filling material can also increase the transmittance of light in the corresponding structural surface; and the filling material set in the non-topmost structural surface can also provide necessary support for the upper structural surface.

[0054] See also Figure 1 or Figure 2 In one embodiment, the micro-nano structure included in at least one structural surface of the double-sided multi-layer metalens is spaced apart from the lower surface of the structural surface where the micro-nano structure is located.

[0055] Specifically, there are N layers of structure surfaces on the first surface, N ≥ 2. For the N layers of structure surfaces on the first surface, the micro-nano structures 111 in the first layer of structure surface 11 and the lower surface of the first structure surface 11 (at Figure 1 or Figure 2In the illustrated embodiment, the lower surface of the first structural surface 11 is spaced apart from the first surface of the substrate 30 (the lower surface of the second structural surface 12 is coplanar with the upper surface of the first structural surface 11); the micro-nano structure 121 in the second structural surface 12 is spaced apart from the lower surface of the second structural surface 12 (the lower surface of the second structural surface 12 is coplanar with the upper surface of the first structural surface 11); and so on, the micro-nano structure in the N-th structural surface is spaced apart from the lower surface of the N-th structural surface (the lower surface of the N-th structural surface is coplanar with the upper surface of the (N-1)-th structural surface).

[0056] Similarly, let M layers of structure surfaces be provided on the second surface, M ≥ 1. For the M layers of structure surfaces provided on the second surface, the micro-nano structures 211 in the first layer of structure surface 21 and the lower surface of the first layer of structure surface 21 (at Figure 1 or Figure 2 In the illustrated embodiment, the lower surface of the first structural surface 21 is coplanar with the second surface of the substrate 30); when M≥2, the micro-nano structure 221 in the second structural surface 22 is spaced from the lower surface of the second structural surface 22 (the lower surface of the second structural surface 22 is coplanar with the upper surface of the first structural surface 21); and so on, the micro-nano structure in the Mth structural surface is spaced from the lower surface of the Mth structural surface (the lower surface of the Mth structural surface is coplanar with the upper surface of the (M-1)th structural surface).

[0057] Figure 4 A schematic diagram of the structure of a double-sided multi-layer metalens in one embodiment of the present application is shown. Figure 5 A schematic diagram of the structure of a double-sided multi-layer metalens in one embodiment of the present application is shown.

[0058] See also Figure 4 or Figure 5 In one embodiment, the micro-nano structure included in at least one structural surface of the double-sided multi-layer metalens is in contact with the lower surface of the structural surface where the micro-nano structure is located.

[0059] Specifically, there are N layers of structure surfaces on the first surface, N ≥ 2. For the N layers of structure surfaces on the first surface, the micro-nano structures 111 in the first layer of structure surface 11 and the lower surface of the first structure surface 11 (at Figure 4 or Figure 5 In the illustrated embodiment, the lower surface of the first structural surface 11 is in contact with the first surface of the substrate 30 (the lower surface of the second structural surface 12 is coplanar with the upper surface of the first structural surface 11); the micro-nano structure 121 in the second structural surface 12 is in contact with the lower surface of the second structural surface 12 (the lower surface of the second structural surface 12 is coplanar with the upper surface of the first structural surface 11); and so on, the micro-nano structure in the N-th structural surface is in contact with the lower surface of the N-th structural surface (the lower surface of the N-th structural surface is coplanar with the upper surface of the (N-1)-th structural surface).

[0060] Similarly, let M layers of structure surfaces be provided on the second surface, M ≥ 1. For the M layers of structure surfaces provided on the second surface, the micro-nano structures 211 in the first layer of structure surface 21 and the lower surface of the first layer of structure surface 21 (at Figure 4 or Figure 5 In the illustrated embodiment, the lower surface of the first-layer structural surface 21 is in contact with the second surface of the substrate 30 (being coplanar); when M≥2, the micro-nanostructure 221 in the second-layer structural surface 22 is in contact with the lower surface of the second-layer structural surface 22 (the lower surface of the second-layer structural surface 22 is coplanar with the upper surface of the first-layer structural surface 21); and so on, the micro-nanostructure in the M-th-layer structural surface is in contact with the lower surface of the M-th-layer structural surface (the lower surface of the M-th-layer structural surface is coplanar with the upper surface of the (M-1)-th-layer structural surface).

[0061] It should be noted that although Figure 1 and Figure 2 In the structure, the micro-nano structures contained in each layer of the structure surface are separated from the lower surface of the corresponding structure surface, and Figure 4 and Figure 5 In the embodiment of the present application, the micro-nano structures contained in each layer of the structural surface are in contact with the lower surface of the corresponding structural surface, but this does not mean that in the embodiment of the present application, for each layer of the structural surface arranged on both sides of the substrate 30, the positional relationship between the micro-nano structures contained therein and their lower surfaces must be consistent with each other, nor does it mean that in the embodiment of the present application, for each layer of the structural surface arranged on the same surface of the substrate 30, the positional relationship between the micro-nano structures contained therein and their lower surfaces must be consistent with each other.

[0062] In detail, in the embodiment of the present application, for each layer of structural surfaces provided on both sides of the substrate 30, the micro-nano structures included in each layer of structural surfaces on one side may be separated from its lower surface, while the micro-nano structures included in each layer of structural surfaces on the other side may be in contact with its lower surface; and, for each layer of structural surfaces provided on the same surface of the substrate 30, the micro-nano structures included in some structural surfaces may be separated from its lower surface, while the micro-nano structures included in other structural surfaces may be in contact with its lower surface.

[0063] Figure 6 FIG. 2 shows a schematic diagram of the structure of a double-sided multilayer metal lens in an embodiment of the present application. Figure 6 In one embodiment, the first layer structure surface 11 disposed on the first surface of the substrate 30 is provided with a positioning mark 113 in addition to the array of micro-nano structures 111. Similarly, the second layer structure surface 21 disposed on the second surface of the substrate 30 is provided with a positioning mark 213 in addition to the array of micro-nano structures 211.

[0064] In this embodiment, positioning marks are provided on the first layer structure surfaces on both sides of the substrate 30 , which is helpful for accurately controlling the relative positions of the micro-nano structure arrays on both sides of the substrate 30 .

[0065] Figure 7 A top view of a first layer structure surface 11 provided on a first surface in an embodiment of the present application is shown. Figure 8 A top view of a second layer structure surface 21 provided on the second surface in one embodiment of the present application is shown. Figure 7 Observation direction and Figure 8 The observation direction is that the base 30 is the center plane and the mirror images are formed. Figure 7 and Figure 8 In one embodiment, the projections of the positioning marks of the first layer structural surface 11 disposed on the first surface and the first layer structural surface 21 disposed on the second surface on the parallel plane of the substrate 30 overlap with each other; that is, the projections of the positioning mark 113 and the positioning mark 213 on the parallel plane of the substrate 30 overlap with each other.

[0066] In one embodiment, all non-uppermost structural surfaces disposed on the first surface are provided with positioning marks in addition to the micro-nano structure array. Similarly, all non-uppermost structural surfaces disposed on the second surface are provided with positioning marks in addition to the micro-nano structure array.

[0067] Specifically, let N layers of structural surfaces be provided on the first surface, where N≥2. Then, from the first structural surface to the (N-1)th structural surface, each structural surface is provided with a positioning mark in addition to the micro-nano structure array.

[0068] Similarly, let M layers of structural surfaces be provided on the second surface, M≥1. Then when M≥2, from the first structural surface to the (M-1)th structural surface, each structural surface is provided with a positioning mark in addition to the micro-nano structure array.

[0069] In this way, when the N layers of structural surfaces on the first surface are prepared layer by layer from bottom to top, except for the Nth layer of structural surface, the positioning marks in each layer of structural surface can provide accurate positioning references for the adjacent layer of structural surfaces prepared thereon (for example: on the first surface, the positioning marks in the first layer of structural surface can provide accurate positioning references for the second layer of structural surface, and the positioning marks in the second layer of structural surface can provide accurate positioning references for the third layer of structural surface, and so on), which is conducive to accurately controlling the relative positions between the micro-nano structure arrays in each layer of structural surface on the first surface.

[0070] Similarly, when the M-layer structural surface on the second surface is also prepared layer by layer from bottom to top, it is also beneficial to accurately control the relative positions between the micro-nano structure arrays in each layer of the structural surface on the second surface.

[0071] In one embodiment, the projections of the positioning marks of all non-uppermost structural surfaces disposed on the same surface of the substrate 30 do not overlap with each other on the parallel planes of the substrate 30 .

[0072] Specifically, there are N layers of structural surfaces on the first surface, where N≥2. Then, from the first layer of structural surface to the (N-1)th layer of structural surface, the projections of the positioning marks in each layer of structural surface on the parallel plane of the substrate 30 do not overlap.

[0073] Similarly, let M layers of structural surfaces be provided on the second surface, M≥1. Then when M≥2, from the first layer of structural surface to the (M-1)th layer of structural surface, the projections of the positioning marks in each layer of structural surface on the parallel plane of the substrate 30 do not overlap.

[0074] In this way, mutual interference among the positioning marks in each layer of the structural surface on the same side surface is avoided, especially when the (T+1) layer of the structural surface is prepared based on the positioning mark in the T layer of the structural surface on the same side surface, the positioning mark in the (T-1) layer of the structural surface interferes with the positioning mark in the T layer of the structural surface, T>1.

[0075] Fig. 9 A top view of a second layer structure surface 12 provided on the first surface in one embodiment of the present application is shown. Fig. 9 Observation direction and Figure 7 The observation direction is the same. So see Figure 7 and Fig. 9 It can be seen that in one embodiment, when the first structural surface 11 is observed from a specific direction, its two positioning marks 113 are arranged vertically; when the second structural surface 12 is observed from the same direction, its two positioning marks 123 are arranged horizontally.

[0076] It can be seen that the projections of the positioning mark 113 in the first layer structure surface 11 and the positioning mark 123 in the second layer structure surface 12 on the parallel plane of the substrate 30 do not overlap each other. Therefore, when the third layer structure surface is prepared on the first surface based on the positioning mark 123 in the second layer structure surface 12, the positioning mark 113 in the first layer structure surface 11 will not interfere with the positioning mark 123.

[0077] As described above, after the structural surfaces are respectively provided on the two side surfaces of the substrate 30, the obtained metalens can be regarded as two single-sided metalens that share the substrate 30. Therefore, in one embodiment, the substrate 30 and at least two layers of structural surfaces provided on the first surface together constitute the first metalens. In addition, the substrate 30 and at least two layers of structural surfaces provided on the second surface together constitute the second metalens.

[0078] In this embodiment, the position deviation between the optical center of the first metalens and the optical center of the second metalens is less than a preset optical center position deviation threshold, that is, the optical center of the first metalens matches the optical center position of the second metalens. As a result, the first metalens and the second metalens can cooperate well with each other in the same optical system, and thus jointly exert expected performance.

[0079] In one embodiment, the position deviation between the respective micro-nano structure arrays of all the structural surfaces disposed on the same surface of the substrate 30 is less than a preset micro-nano position deviation threshold, that is, the positions of the respective micro-nano structure arrays of all the structural surfaces on the same surface match. Thus, the performance of the first metalens formed by the substrate 30 and all the structural surfaces on the first surface meets expectations, and the performance of the second metalens formed by the substrate 30 and all the structural surfaces on the second surface meets expectations.

[0080] It should be noted that the structural surface is usually obtained by processing according to the following process flow: first prepare the structural layer, then perform photolithography and etching on the structural layer (optionally, the etched structural layer can be further filled with a filling material), that is, the structural surface is processed. In some cases, in order to reduce the difficulty of preparing the structural layer and reduce the risk of damage to the substrate 30 during the processing, the following process flow is used to obtain a double-sided multilayer metalens:

[0081] A first intermediate substrate and a second intermediate substrate different from the substrate 30 are selected (when the double-sided multilayer metalens target works in the visible light band or the near-infrared band, the substrate 30 is a quartz wafer, and the first intermediate substrate and the second intermediate substrate are both silicon wafers).

[0082] First, prepare a first oxide layer on the first intermediate substrate (when the double-sided multilayer metalens target works in the visible light band or the near-infrared band, the first oxide layer can be selected from silicon dioxide), then prepare a first structural layer on the first oxide layer, then perform photolithography and etching on the first structural layer, and then fill the filling material, that is, process the first structural surface on the first intermediate substrate. Then continue to process layer by layer, and finally obtain N structural surfaces on the first intermediate substrate, N≥2. Then the N-th structural surface on the first intermediate substrate is bonded to the first surface of the substrate 30, and finally the first intermediate substrate is removed, so that the N-th structural surface is transferred to the first surface of the substrate 30. Thus, the N-th structural surface on the first intermediate substrate becomes the first structural surface 11 on the first surface of the substrate 30; the first structural surface on the first intermediate substrate is called the uppermost structural surface on the first surface of the substrate 30; at the same time, the first oxide layer is disposed on the upper surface of the uppermost structural surface on the first surface of the substrate 30, and is exposed to the air.

[0083] Similarly, a second oxide layer is prepared on the second intermediate substrate (when the double-sided multilayer metalens target works in the visible light band or the near-infrared band, the second oxide layer can be selected from silicon dioxide), and then finally the M-layer structural surface is processed on the second intermediate substrate, where M≥1. Then the M-th layer structural surface on the second intermediate substrate is bonded to the second surface of the substrate 30, and finally the second intermediate substrate is removed, so that the M-layer structural surface is transferred to the second surface of the substrate 30. Thus, the M-th layer structural surface on the second intermediate substrate becomes the first layer structural surface 21 on the second surface of the substrate 30; the first layer structural surface on the second intermediate substrate becomes the uppermost layer structural surface on the second surface of the substrate 30; at the same time, the second oxide layer is disposed on the upper surface of the uppermost layer structural surface on the second surface of the substrate 30, and is exposed to the air.

[0084] Thus, in one embodiment, the uppermost structural surface on the first surface of the substrate 30 is provided with a filling material, and the upper surface of the uppermost structural surface of the first surface is provided with a first oxide layer. Similarly, the uppermost structural surface on the second surface of the substrate 30 is provided with a filling material, and the upper surface of the uppermost structural surface of the second surface is provided with a second oxide layer.

[0085] Fig.10 FIG. 2 shows a schematic diagram of the structure of a double-sided multilayer metal lens in an embodiment of the present application. Fig.10In this embodiment, the substrate 30 may be a quartz wafer. The uppermost structural surface on the first surface of the substrate 30 is the second structural surface 12. The second structural surface 12 is provided with a filling material, and a first oxide layer 100 is provided on the upper surface of the second structural surface 12. The uppermost structural surface on the second surface of the substrate 30 is the second structural surface 22. The second structural surface 22 is provided with a filling material, and a second oxide layer 200 is provided on the upper surface of the second structural surface 22.

[0086] In one embodiment, on the same surface of the substrate 30 , at least one layer of structure surface includes a micro-nano structure array entirely composed of positive micro-nano structures.

[0087] Among them, the positive micro-nano structure refers to the micro-nano structure formed by the remaining part of the structural layer after the structural layer is etched. From another perspective, if the structural layer is etched without filling the filling material, the columnar shape is the positive micro-nano structure. It should be noted that the "columnar" here is not used to limit the shape of the micro-nano structure, but is only used to explain that the material constituting the positive micro-nano structure is not air.

[0088] In detail, in this embodiment, on the first surface of the substrate 30, only one layer of the micro-nano structure array contained in the structure surface may be composed entirely of positive micro-nano structures, or multiple layers of the micro-nano structure array contained in the structure surface may be composed entirely of positive micro-nano structures, or all the micro-nano structure arrays contained in the structure surface may be composed entirely of positive micro-nano structures. Similarly, on the second surface of the substrate 30, only one layer of the micro-nano structure array contained in the structure surface may be composed entirely of positive micro-nano structures, or multiple layers of the micro-nano structure array contained in the structure surface may be composed entirely of positive micro-nano structures, or all the micro-nano structure arrays contained in the structure surface may be composed entirely of positive micro-nano structures.

[0089] In one embodiment, on the same surface of the substrate 30 , at least one layer of structure surface includes a micro-nano structure array entirely composed of negative micro-nano structures.

[0090] Among them, the negative micro-nano structure refers to the micro-nano structure formed by the removed part of the structural layer after the structural layer is etched. From another perspective, if the structural layer is etched and no filling material is filled, the hole-shaped is a negative micro-nano structure. It should be noted that the "hole-shaped" here is only used to explain that when the filling material is not filled, the material constituting the negative micro-nano structure is air.

[0091] In detail, in this embodiment, on the first surface of the substrate 30, only one layer of the micro-nano structure array contained in the structure surface may be entirely composed of negative micro-nano structures, or multiple layers of the micro-nano structure array contained in the structure surface may be entirely composed of negative micro-nano structures, or all the micro-nano structure arrays contained in the structure surface may be entirely composed of negative micro-nano structures. Similarly, on the second surface of the substrate 30, only one layer of the micro-nano structure array contained in the structure surface may be entirely composed of negative micro-nano structures, or multiple layers of the micro-nano structure array contained in the structure surface may be entirely composed of negative micro-nano structures, or all the micro-nano structure arrays contained in the structure surface may be entirely composed of negative micro-nano structures.

[0092] In one embodiment, on the same surface of the substrate 30 , at least one layer of the structure surface includes a micro-nano structure array entirely composed of positive micro-nano structures, and at least one layer of the structure surface includes a micro-nano structure array entirely composed of negative micro-nano structures.

[0093] In detail, in this embodiment, on the first surface of the substrate 30, at least one layer of structural surface includes a micro-nano structure array composed entirely of positive micro-nano structures, and at least one layer of structural surface includes a micro-nano structure array composed entirely of negative micro-nano structures (for example: three layers of structural surfaces are provided on the first surface of the substrate 30, of which two layers of structural surfaces include micro-nano structure arrays composed entirely of positive micro-nano structures, and another layer of structural surface includes micro-nano structure arrays composed entirely of negative micro-nano structures).

[0094] Alternatively, on the second surface of the substrate 30, when a plurality of structural surfaces are provided, the micro-nano structure array contained in at least one layer of the structural surfaces is entirely composed of positive micro-nano structures, and the micro-nano structure array contained in at least one layer of the structural surfaces is entirely composed of negative micro-nano structures (for example: four layers of structural surfaces are provided on the second surface of the substrate 30, of which the micro-nano structure arrays contained in two layers of the structural surfaces are entirely composed of positive micro-nano structures, and the micro-nano structure arrays contained in the other two layers of the structural surfaces are entirely composed of negative micro-nano structures).

[0095] Since the dispersion curve of the positive micro-nanostructure and the dispersion curve of the negative micro-nanostructure have opposite changing trends, setting a single-layer micro-nanostructure with consistent positive and negative but a multi-layer structure surface with mixed positive and negative micro-nanostructures in different layers on the same side surface is beneficial to the double-sided multi-layer metalens to achieve chromatic aberration compensation.

[0096] Fig.11 FIG. 2 shows a schematic diagram of the structure of a double-sided multilayer metal lens in an embodiment of the present application. Fig.11In this embodiment, on the first surface of the substrate 30, the micro-nano structures 111 in the first layer structure surface 11 are all positive micro-nano structures, and the micro-nano structures 121 in the second layer structure surface 12 are all negative micro-nano structures. Similarly, on the second surface of the substrate 30, the micro-nano structures 211 in the first layer structure surface 21 are all positive micro-nano structures, and the micro-nano structures 221 in the second layer structure surface 22 are all negative micro-nano structures.

[0097] Those skilled in the art will readily appreciate other embodiments of the present application after considering the specification and practicing the utility model disclosed herein. The present application is intended to cover any modification, use or adaptation of the present application, which follows the general principles of the present application and includes common knowledge or customary techniques in the art that are not disclosed in the present application. The specification and examples are intended to be exemplary only, and the true scope and spirit of the present application are indicated by the appended claims.

Claims

1. A double-sided multi-layer metalens, characterized in that: The double-sided multi-layer metalens is provided with a substrate; On the first surface of the substrate, at least two layers of structure surfaces are sequentially arranged in a direction perpendicular to the first surface; On the second surface of the substrate, at least one layer of structure surfaces is sequentially arranged in a direction perpendicular to the second surface; Each structural surface is provided with a micro-nano structure array.

2. The double-sided multilayer metalens according to claim 1, characterized in that Among all the structural surfaces arranged on the same surface of the substrate, at least all the structural surfaces other than the uppermost layer are also provided with filling materials.

3. The double-sided multi-layer metalens according to claim 1, characterized in that The micro-nano structure included in at least one structural surface of the double-sided multi-layer metalens is spaced apart from the lower surface of the structural surface where the micro-nano structure is located.

4. The double-sided multilayer metalens according to claim 1, characterized in that The micro-nano structure included in at least one structural surface of the double-sided multi-layer metalens is in contact with the lower surface of the structural surface where the micro-nano structure is located.

5. The double-sided multi-layer metalens according to claim 1, characterized in that The substrate and at least two structural surfaces arranged on the first surface together constitute a first super lens; the substrate and at least one structural surface arranged on the second surface together constitute a second super lens; Wherein, the position deviation between the optical center of the first super lens and the optical center of the second super lens is less than a preset optical center position deviation threshold.

6. The double-sided multi-layer metalens according to claim 1, characterized in that The position deviations between the respective micro-nano structure arrays of all the structure surfaces arranged on the same surface of the substrate are smaller than a preset micro-nano structure position deviation threshold.

7. The double-sided multi-layer metalens according to claim 1, characterized in that The uppermost structural surface on the first surface is provided with a filling material, and the upper surface of the uppermost structural surface on the first surface is provided with a first oxide layer; A filling material is disposed on the uppermost structural surface of the second surface, and a second oxide layer is disposed on the upper surface of the uppermost structural surface of the second surface.

8. The double-sided multi-layer metalens according to claim 1, characterized in that On the same surface of the substrate, at least one layer of structure surface includes a micro-nano structure array entirely composed of positive micro-nano structures.

9. The double-sided multi-layer metalens according to claim 1, characterized in that On the same surface of the substrate, at least one layer of structure surface includes a micro-nano structure array entirely composed of negative micro-nano structures.

10. The double-sided multi-layer metalens according to claim 1, characterized in that On the same surface of the substrate, at least one layer of the structure surface includes a micro-nano structure array composed entirely of positive micro-nano structures, and at least one layer of the structure surface includes a micro-nano structure array composed entirely of negative micro-nano structures.

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