Superlens and image sensor

Abstract

The application provides an ultralens and an image sensor. The ultralens comprises a plurality of micro-nano units arranged in an array, each of the micro-nano units comprising a substrate and a phase modulation structure arranged on the substrate, the phase modulation structure having a preset phase distribution for regulating a focusing depth of incident light, so that incident light in the same waveband is focused to the same depth. The ultralens of the application can eliminate chromatic aberration, improve photoelectron conversion efficiency, and thus improve quantum efficiency and image quality stability.

Description

Technical Field

[0001] This application relates to the field of lens technology, and in particular to a superlens and image sensor. Background Technology

[0002] Traditional microlens arrays consist of periodically arranged small curved lenses. Incident light has a wavelength distribution within a certain band, and a single microlens cannot completely eliminate chromatic aberration; therefore, the incident light will be focused to different depths. This inconsistent focusing depth within a specific wavelength band leads to varying photoelectron conversion efficiencies, thus affecting the final quantum efficiency. Furthermore, the focusing depth of incident light in traditional microlens arrays is not adjustable, making it difficult to optimize their quantum efficiency. Summary of the Invention

[0003] This application provides an improved superlens and image sensor.

[0004] This application provides a superlens, comprising: a plurality of micro-nano units arranged in an array, each of the micro-nano units including a substrate and a phase modulation structure disposed on the substrate, the phase modulation structure having a preset phase distribution for controlling the focusing depth of incident light, so that incident light in the same wavelength band is focused to the same depth.

[0005] Preferably, the different phase modulation structures located within different micro / nano units have preset different phase distributions, which are used to control incident light in different wavelength bands to be focused to the same depth.

[0006] Preferably, the different phase modulation structures located within different micro / nano units have preset different phase distributions, which are used to control the incident light located in different wavelength bands to be focused to different depths.

[0007] Preferably, the phase distribution preset by the phase modulation structure is determined at least based on the lens focal length, lens radius and wavelength of the incident light of the superlens.

[0008] Preferably, at the same location as the superlens, the phase distribution of the phase modulation structure is positively correlated with the wavelength of the incident light.

[0009] Preferably, the phase distribution of the phase modulation structure is symmetrically arranged relative to the central axis of the micro / nano unit.

[0010] Preferably, the preset phase distribution of the phase modulation structure is expressed by the following formula:

[0011]

[0012] in, Used to represent the phase distribution of the phase modulation structure;

[0013] i is used to represent the wavelength of the incident light;

[0014] j is used to represent the number of terms in the phase;

[0015] A ij Used to represent coefficients;

[0016] ρ is used to represent the normalized radial coordinate;

[0017] x and y are used to represent the position coordinates of the superlens;

[0018] R0 is used to represent the radius of the superlens.

[0019] Preferably, the phase modulation structure is also used to control the focusing position of the incident light so that the focusing position of the incident light is located on the central axis of the micro / nano unit.

[0020] Preferably, the phase modulation structure includes multiple micro-nano structures, which are arranged at intervals, and each micro-nano structure is a symmetrical structure.

[0021] Preferably, the plurality of micro- and nanostructures are symmetrically distributed along the X-axis and / or Y-axis in the same plane.

[0022] Preferably, the two symmetrically distributed micro / nano structures are complementary structures, one of which is a columnar structure and the other is a perforated structure.

[0023] Preferably, the height of the plurality of micro / nano structures relative to the substrate is consistent.

[0024] Preferably, the cross-section of the micro / nano structure is a regular or irregular shape formed by straight edges, curved edges, or both straight and curved edges.

[0025] Preferably, the material of the micro / nano structure includes semiconductor materials.

[0026] Preferably, the substrate is made of a transparent material.

[0027] This application also provides an image sensor, comprising: a superlens, a filter layer, a silicon layer, and a circuit layer as described in any of the above embodiments; the superlens, the filter layer, the silicon layer, and the circuit layer are arranged sequentially from top to bottom.

[0028] The superlens and image sensor of this application are described in embodiments. The superlens of this application has multiple micro-nano units arranged in an array. Each micro-nano unit has a phase modulation structure with a preset phase distribution. This phase modulation structure can effectively control the focusing depth of the incident light, so that incident light in the same wavelength band is focused to the same depth, which can eliminate chromatic aberration in that wavelength band, improve photoelectric conversion efficiency, and thus improve quantum efficiency and image quality stability. Attached Figure Description

[0029] Figure 1 The diagram shown is a structural schematic of an embodiment of the image sensor of this application.

[0030] Figure 2 As shown Figure 1 A schematic diagram of another embodiment of the image sensor is shown.

[0031] Figure 3 The diagram shows the focusing state of two wavelengths of incident light passing through the superlens of this application.

[0032] Figure 4 As shown Figure 3 A schematic diagram of one embodiment of the superlens shown.

[0033] Figure 5 As shown Figure 4 The diagram shows a top view of the phase modulation structure of the micro / nano unit of the superlens.

[0034] Figure 6 As shown Figure 4 The diagram shows a top view of the complementary structure of the micro / nano units of the superlens.

[0035] Figure 7 As shown Figure 4 The phase distribution diagram of the phase modulation structure of the micro / nano unit of the superlens is shown.

[0036] Figure 8 The diagram shows a comparison of the actual and ideal phases obtained by the phase modulation structure of the micro / nano unit of the superlens of this application with various incident wavelengths.

[0037] Figure 9 The diagram shows the focal distribution of a conventional microlens and the superlens of this application across the entire visible light spectrum. Detailed Implementation

[0038] The superlens and image sensor of this application will now be described in detail with reference to the accompanying drawings. Unless otherwise specified, the features of the following embodiments and implementations can be combined with each other.

[0039] In camera systems, most use image sensors (CMOS Image Sensor, CIS) for image acquisition. For example... Figure 1 and Figure 2As shown, the image sensor 1 includes a superlens 10, a filter layer 20, a silicon layer 30, and a circuit layer 40. The superlens 10, filter layer 20, silicon layer 30, and circuit layer 40 are arranged sequentially from top to bottom. The superlens 10 collects incident light, focusing it downwards. After passing through the filter layer 20 (which can be a filter, typically an RGB Bayer array) with RGB (red, green, and blue color channels) arrangement, the light reaches the silicon layer 30 and circuit layer 40, where the light signal is converted into an electrical signal, thus recording intensity information and reproducing the image. To enhance quantum efficiency (the efficiency of converting light signals into electrical signals), the superlens 10's ability to focus incident light is crucial. If the superlens 10 can achieve good focusing of incident light in the visible light band, converging the light onto the silicon layer, the conversion rate of photons and electrons can be improved, thus enhancing quantum efficiency.

[0040] Therefore, this application provides a superlens 10 that can effectively control the focusing depth of incident light, so that incident light in the same wavelength band is focused to the same depth, thereby eliminating chromatic aberration in that wavelength band and improving photoelectron conversion efficiency.

[0041] Combination Figures 1 to 3 As shown, the superlens 10 includes multiple micro / nano units 11 arranged in an array. The array arrangement of the multiple micro / nano units 11 can be similar to that of pixel unit arrays, for example, they can be arranged periodically or adjacently in the same plane. The size of the micro / nano units 11 is adapted to the size of the pixel units. Each micro / nano unit 11 includes a substrate 12 and a phase modulation structure 13 disposed on the substrate 12. The substrate 12 provides physical support for the phase modulation structure 13 and cooperates with the phase modulation structure 13 to realize the optical modulation function. The phase modulation structure 13 has a preset phase distribution. The phase modulation structure 13 is an optical element with a specific function, designed to have a preset phase change pattern according to a specific rule inside or on its surface. This phase change pattern can be understood as one of the state parameters of the incident light during propagation, which determines the vibration state of the incident light at different positions and times. The phase modulation structure 13 is used to control the focusing depth of the incident light, so that incident light in the same wavelength band is focused to the same depth. The phase modulation structure 13 controls and adjusts the incident light, changing its focusing position during propagation. The focusing depth refers to the depth at which the incident light converges to the silicon layer 30 after modulation. When incident light passes through the phase modulation structure 13 with a preset phase distribution, incident light within the same wavelength range (same band) will be adjusted and focused to the same depth. In other words, the phase modulation structure 13 can achieve specific and consistent focusing control for light within the same band, ensuring that the incident light ultimately focuses to the same depth during propagation, thus achieving precise control and adjustment of the light focusing characteristics.

[0042] The superlens 10 of this application has multiple micro-nano units 11 arranged in an array. Each micro-nano unit 11 has a phase modulation structure 13 with a preset phase distribution. The phase modulation structure 13 can effectively control the focusing depth of the incident light, so that the incident light in the same band is focused to the same depth, which can eliminate the chromatic aberration in the band, improve the photoelectron conversion efficiency, and thus improve the quantum efficiency and image quality stability.

[0043] exist Figure 1 In the illustrated embodiment, the incident light is visible light, including, for example, red, green, and blue light. For example, the wavelength range of red light is 600nm-700nm. The wavelength range of green light is 500nm-600nm. The wavelength range of blue light is 400nm-500nm. When red, green, or blue light located in the same wavelength band (e.g., 600nm-700nm, 500nm-600nm, or 400nm-500nm) passes through the phase modulation structure 13 with a preset phase distribution and then through the filter layer 20 with RGB (red, green, and blue color channels) arrangement, the red, green, or blue light located in the same wavelength band will be adjusted and focused onto the same depth position of the silicon layer 30. With this configuration, the phase modulation structure 13 can effectively control the focusing depth of red, blue, or green light, so that red light, green light, or blue light in the same wavelength band converge at the same focal position, without color difference, and have the same focal depth in the silicon layer 30, thereby improving photoelectron conversion efficiency, and thus improving quantum efficiency and image quality stability.

[0044] It should be noted that, due to the different refractive indices of red, green, and blue light, they have different refraction angles and focal lengths. Therefore, for each incident light beam within the same wavelength band, different phase distributions are set in the phase modulation structure 13 to achieve focusing to the same depth. In other words, the preset phase distribution used by the phase modulation structure 13 to focus red light to the same depth is different from the preset phase distribution used to focus green or blue light to the same depth. This can be understood as the preset phase distributions used by the phase modulation structure 13 to focus incident light of different wavelength bands to the same depth being different, allowing for independent adjustment of the focusing depth of incident light in different wavelength bands without mutual interference, thus offering high flexibility.

[0045] In some embodiments, different phase modulation structures 13 located within different micro / nano units 11 have preset different phase distributions, used to control incident light from different wavelengths to be focused to the same depth. For example... Figure 1As shown, different phase modulation structures 13 located in different micro / nano units 11 have preset different phase distributions, which can control red, green, and blue light in different wavelength bands to be focused to the same depth. With this configuration, the phase modulation structure 13, by preset different phase distributions, can not only independently modulate the focusing depth of incident light in the same wavelength band to be the same depth, but also control the incident light in different wavelength bands to converge at the same focal position, without color difference, and have the same focusing depth in the silicon layer 30, thereby improving photoelectron conversion efficiency, and thus improving quantum efficiency and image quality stability.

[0046] In some embodiments, different phase modulation structures 13 located within different micro / nano units 11 have preset different phase distributions, used to control incident light in different wavelength bands to be focused to different depths. For example... Figure 2 As shown, different phase modulation structures 13 located within different micro / nano units 11 have preset different phase distributions, which can control the focusing of red and green light in different wavelength bands to the same depth, and can also control the focusing of blue light in different wavelength bands to different depths. Specifically, the 600nm-700nm red light band is focused at the same position. The 500nm-600nm green light band is focused at the same position, and at the same depth as the red light. The 400nm-500nm blue light band is focused at the same position, and at a depth greater than that of the red and green light. This structure can further improve the quantum efficiency of blue light and achieve specific functions. The focusing depths of red, green, and blue light can also be flexibly designed according to specific functions, thereby customizing different quantum efficiency distributions. With this configuration, the phase modulation structure 13, by preset different phase distributions, can not only independently modulate the focusing depth of incident light in the same wavelength band to the same depth, but also control the focusing of incident light in different wavelength bands to the same depth. In addition, it can also adjust the incident light of different wavelengths to focus to different depths, while ensuring chromatic aberration in their respective wavelengths, and flexibly change or adjust the focus depth to achieve customized quantum efficiency distribution, thereby enhancing practicality and image quality.

[0047] In some embodiments, the phase modulation structure 13 is also used to control the focusing position of the incident light, so that the focusing position of the incident light is located on the central axis A of the micro / nano unit 11. Figure 3 In the illustrated embodiment, the focal distribution of incident light of different wavelengths of visible light after passing through the phase modulation structure 13 of the superlens 10 of this application is shown. The solid and dashed lines represent two wavelengths with the same focal length, and the focal points coincide, which can be located on the central axis A of the micro / nano unit 11. This arrangement avoids light crosstalk caused by incident light of different wavelengths focusing at positions deviating from the left or right of the central axis A of the micro / nano unit 11, thus preventing it from affecting image quality.

[0048] like Figures 4 to 6As shown, the phase modulation structure 13 includes multiple micro / nano structures 14, which are arranged at intervals, and each micro / nano structure 14 is a symmetrical structure. These multiple micro / nano structures 14 are equivalent to multiple sub-units, which can work together to achieve a complex and precise preset phase distribution. Each micro / nano structure 14 has a specific influence on the phase of the incident light. Adjacent micro / nano structures 14 can be identical or different. By rationally designing their shape, size, spacing, and arrangement, the phase change of the incident light at different positions can be precisely controlled, thereby accurately regulating the focusing depth of the incident light and ensuring that light in the same wavelength band is precisely focused to the same depth. The symmetrical structure here can be rotated 90° symmetrically. This arrangement ensures that the optical properties of each micro / nano structure 14 are consistent and uniform in all directions, guaranteeing the stability and reliability of the focusing depth regulation of the incident light and preventing significant deviations due to factors such as the angle of the incident light.

[0049] In some embodiments, multiple micro / nanostructures 14 are symmetrically distributed along the X-axis and / or Y-axis in the same plane. In other embodiments, multiple micro / nanostructures 14 are symmetrically distributed along the X-axis in the same plane. Figure 5 In the illustrated embodiment, multiple micro / nano structures 14 are symmetrically distributed along the X and Y axes of the same plane. This arrangement provides uniform and symmetrical phase modulation, ensuring consistency in the focusing depth control of incident light in all directions and improving the all-around performance of the optical system. Furthermore, the micro / nano structures 14 can be flexibly arranged according to the phase distribution, offering high flexibility.

[0050] In some embodiments, the two symmetrically distributed micro / nano structures 14 are complementary structures, one being a columnar structure 141 and the other a perforated structure 142. Figure 5 and Figure 6In the illustrated embodiment, the column structure 141 protrudes relative to the substrate 12, and the perforated structure 142 is hollowed out relative to the column structure 141. The column structure 141 and the perforated structure 142 are sized and shaped to match, with the lateral linewidth of either structure ranging from 50 nm to 200 nm. The complementary characteristics of the column structure 141 and the perforated structure 142 can generate an optical response. The phase delay of the incident light by the column structure 141 differs from that of the perforated structure 142; together, they can achieve a more complex phase distribution within the same plane. By designing the dimensions, shape, depth, and other parameters of the column structure 141 and the perforated structure 142, the phase change of light passing through different regions can be precisely controlled, thereby achieving fine-tuning of the incident light phase and meeting the high-precision phase modulation requirements of specific optical applications. Furthermore, the complementary columnar structure 141 and the perforated structure 142 provide two different phase modulation primitives. Their symmetrical distribution can achieve more diverse phase change combinations in a smaller space, increasing the degree of freedom of phase modulation. This means that higher phase modulation resolution can be achieved, enabling more detailed division and control of the phase of the incident light, which helps to improve the imaging accuracy and beam shaping effect of the optical system.

[0051] In some embodiments, the height of the plurality of micro / nanostructures 14 relative to the substrate 12 is consistent. Figure 4 In the illustrated embodiment, the height of the pillar structure 141 ranges from 100nm to 1000nm. The depth of the perforated structure 142 ranges from 100nm to 1000nm. Setting the same height for the pillar structure 141 and the perforated structure 142 ensures a uniform phase distribution of the phase modulation structure 13, thereby ensuring precise control of the optical path difference of each micro / nano structure 14 and avoiding deviations in focusing depth due to phase errors introduced by height differences. Furthermore, setting the height of multiple micro / nano structures 14 to be consistent makes the surface of the superlens 10 smoother, reduces random scattering of light at the interface, lowers background noise, and improves the quality of the focused spot and energy utilization.

[0052] In some embodiments, the cross-section of the micro / nano structure 14 is a regular or irregular shape formed by straight edges, curved edges, or both straight and curved edges. Figure 5 and Figure 6 In the illustrated embodiments, the cross-section of the micro / nano structure 14 includes other regular structures such as circles, squares, and crosses. The geometric parameters of regular shapes (such as radius, side length, and arm length) are easy to quantify and optimize, and their phase response can be accurately predicted through numerical simulation, reducing design iteration costs. Furthermore, the use of complementary structures with regular shapes (such as circular holes and square pillars) in the micro / nano structure 14 can further balance the optical path difference, improving overall phase uniformity and stability. In other embodiments, other cross-sectional shapes can also be selected, provided they satisfy 90-degree rotational symmetry; no limitation is imposed.

[0053] exist Figure 5 and Figure 6 In the illustrated embodiment, the size of the micro / nano unit 11 is adapted to the size of a single pixel unit, with a side length ranging from 0.5µm to 2µm. Each superlens 10 may contain multiple arrayed micro / nano units 11. For example, in this application, the superlens 10 may include 5*5, 4*4, 6*6, or other numbers of micro / nano units 11, without limitation. The distance between the centers of adjacent columnar structures 141 is determined according to the pixel size and the number of columnar structures 141; for example, this spacing may be set to 0.1µm, 0.2µm, or 0.3µm, etc. On the plane of the superlens 10, the micro / nano units 11 of this application may be symmetrically or asymmetrically distributed. That is, the phase modulation structure 13 of the micro / nano units 11 is arranged according to the required phase, and the shape, size, material, etc. of the specific structure must work together to meet the preset phase arrangement. This setting can effectively control the focusing depth of incident light, so that incident light in at least the same wavelength band is focused to the same depth, eliminating chromatic aberration in that wavelength band, improving photoelectron conversion efficiency, and thus improving quantum efficiency and image quality stability.

[0054] In some embodiments, the material of the micro / nano structure 14 includes a semiconductor material. For example, the material of the pillar structure 141 includes one of silicon, gallium nitride, titanium oxide, and silicon nitride, without limitation. The micro / nano structure 14 prepared using one of the above materials can precisely fabricate complementary structures of pillars and vias, ensuring phase modulation accuracy. In some embodiments, the material of the substrate 12 includes a transparent material. The material of the substrate 12 includes one of glass and sapphire. Using one of the above materials for the substrate 12 can improve overall performance and reliability.

[0055] In some embodiments, the phase distribution preset by the phase modulation structure 13 is determined at least based on the lens focal length, lens radius, and wavelength of the incident light of the superlens 10. The preset phase distribution of the phase modulation structure 13, through the synergistic optimization of the lens focal length, lens radius, and wavelength of the incident light of the superlens 10, can achieve high-precision focusing, maintain consistent focusing depth of the incident light, eliminate chromatic aberration, and improve photoelectric conversion efficiency, thereby enhancing quantum efficiency and image quality stability.

[0056] Specifically, the preset phase distribution of the phase modulation structure 13 is expressed by the following formula:

[0057]

[0058] in, Used to represent the phase distribution of phase modulation structure 13. 'i' represents the wavelength of the incident light. 'j' represents the number of phase terms. A ijUsed to represent coefficients. ρ is used to represent normalized radial coordinates. x and y are used to represent the position coordinates of superlens 10. R0 is used to represent the radius of superlens 10.

[0059] Based on the two formulas above, the following can be achieved: Figure 7 The phase distribution of the achromatic phase modulation structure 13 shown. For example... Figure 7 As shown, the horizontal axis represents the radial coordinate (R / um) on the superlens 10, and the vertical axis represents the phase. The incident wavelengths are 400nm, 450nm, 500nm, 550nm, 600nm, 650nm, and 700nm, and each curve represents the phase distribution obtained after passing through the phase modulation structure 13 at that wavelength. Table 1 lists the coefficients in the formulas. There are two terms for each wavelength, for a total of seven wavelengths.

[0060] Table 1

[0061] wavelength 400nm 450nm 500nm 550nm 600nm 650nm 700nm A1 -0.981 -0.872 -0.785 -0.714 -0.654 -0.604 -0.561 A2 0.0145 0.0129 0.0116 0.0106 0.0097 0.0089 0.0083

[0062] Here, A1 and A2 represent the coefficients at different wavelengths, which are set by the user according to their needs. For different wavelengths, each position has a different phase.

[0063] exist Figure 7 In the illustrated embodiment, the phase distribution of the phase modulation structure 13, located at the same position on the superlens 10, is positively correlated with the wavelength of the incident light. For example, when the radial coordinate of the superlens 10 is 0.4 μm, the larger the incident wavelength, the larger the phase of the phase modulation structure 13. Similarly, the smaller the incident wavelength, the smaller the phase of the phase modulation structure 13. This configuration enables panchromatic focusing with a single lens, simplifies the complexity of the imaging system, supports multi-wavelength multiplexing or wide-spectrum applications, reduces dependence on structural height, improves fabrication feasibility, and provides a design basis for dynamically tunable superlenses.

[0064] exist Figure 7 In the illustrated embodiment, the phase distribution of the phase modulation structure 13 is symmetrically arranged relative to the central axis A of the micro / nano unit 11. Figure 7 In the illustrated embodiment, the phases of different incident wavelengths on both sides of the radial coordinate O (position A of the central axis of the micro / nano unit 11) of the superlens 10 are symmetrically consistent. This configuration allows for controllability of the focused depth of the incident light to maintain consistency, eliminating chromatic aberration, improving photoelectron conversion efficiency, and thus enhancing quantum efficiency and image quality stability.

[0065] like Figure 8As shown, the horizontal axis represents the radial coordinate (R / um) on the superlens 10, and the vertical axis represents the phase. The dashed lines represent the ideal phase distribution after passing through the superlens 10 when the incident wavelengths are 400nm, 450nm, 500nm, 550nm, 600nm, 650nm, and 700nm. The six symbols represent the six phase modulation structures 13 arranged on the plane of the superlens 10, and the phase they refer to is the phase value obtained after each wavelength passes through this structure. For various incident wavelengths, the actual phase obtained after passing through the phase modulation structure 13 of this application matches the ideal phase, ensuring achromatic focusing.

[0066] like Figure 9 As shown, the focal distribution of a conventional microlens and the superlens 10 of this application is illustrated across the entire visible light spectrum. Figure 9 In the diagram, the horizontal axis represents wavelength (nm), and the vertical axis represents focal point offset (µm). The solid line represents a traditional microlens, where the incident light wavelength ranges from 410nm to 700nm, and the focal point position varies. The dashed line represents the improved superlens 10 of this application, where the focal point remains unchanged throughout the entire visible light band.

[0067] The superlens 10 of this application includes micro / nano units 11 based on the principle of diffraction. When incident light of different wavelengths passes through the superlens 10, different phase distributions are obtained. By precisely designing the structure of the superlens 10, incident light in the 400nm-700nm range can be focused at the same depth, thereby achieving an achromatic superlens across the entire visible light band. This superlens 10 can eliminate chromatic aberration across the entire visible light band, ensuring that red, green, and blue light of various wavelengths are focused at the same depth in the silicon layer, thus significantly improving quantum efficiency and image quality stability. Thanks to the uniform focusing depth across the entire band in the silicon layer 30, the quantum efficiency of the image sensor is improved, especially for short wavelengths, which are significantly enhanced. Furthermore, red, green, and blue light can be independently modulated, flexibly changing the focusing depth while ensuring achromatic aberration in their respective bands, achieving a customized quantum efficiency distribution, greatly enhancing practicality and image quality performance. Moreover, it is manufactured using mature semiconductor processes, compatible with image sensor technology, improving processing and assembly efficiency and reducing the cost of the image sensor.

[0068] It should be understood that this application is not limited to the content already described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.

Claims

1. A superlens, characterized in that, include: Multiple micro / nano units arranged in an array, each micro / nano unit including a substrate and a phase modulation structure disposed on the substrate, the phase modulation structure having a preset phase distribution for controlling the focusing depth of incident light, so that incident light in the same wavelength band is focused to the same depth.

2. The superlens according to claim 1, characterized in that, Different phase modulation structures located within different micro / nano units have preset different phase distributions, used to control incident light from different wavelengths to be focused to the same depth; or The different phase modulation structures located within the different micro / nano units have preset different phase distributions, which are used to control the incident light located in different wavelength bands to be focused to different depths.

3. The superlens according to claim 1, characterized in that, The phase distribution preset by the phase modulation structure is determined at least based on the lens focal length, lens radius and wavelength of the incident light of the superlens.

4. The superlens according to claim 1 or 3, characterized in that, Located at the same position as the superlens, the phase distribution of the phase modulation structure is positively correlated with the wavelength of the incident light.

5. The superlens according to claim 1 or 3, characterized in that, The phase distribution of the phase modulation structure is symmetrically arranged relative to the central axis of the micro / nano unit.

6. The superlens according to claim 1 or 3, characterized in that, The preset phase distribution of the phase modulation structure is expressed by the following formula: in, Used to represent the phase distribution of the phase modulation structure; i is used to represent the wavelength of the incident light; j is used to represent the number of terms in the phase; A ij Used to represent coefficients; ρ is used to represent the normalized radial coordinate; x and y are used to represent the position coordinates of the superlens; R0 is used to represent the radius of the superlens.

7. The superlens according to claim 1, characterized in that, The phase modulation structure is also used to control the focusing position of the incident light so that the focusing position of the incident light is located on the central axis of the micro / nano unit.

8. The superlens according to claim 1, characterized in that, The phase modulation structure includes multiple micro-nano structures, which are arranged at intervals, and each micro-nano structure is a symmetrical structure. The multiple micro / nanostructures are symmetrically distributed along the X-axis and / or Y-axis in the same plane; and / or The two symmetrically distributed micro / nano structures are complementary structures, one of which is a columnar structure and the other is a perforated structure.

9. The superlens according to claim 8, characterized in that, The multiple micro / nanostructures maintain a consistent height relative to the substrate; and / or The cross-section of the micro / nanostructure is a regular or irregular shape formed by straight edges, curved edges, or both straight and curved edges; and / or The materials of the micro / nanostructures include semiconductor materials; and / or The substrate is made of a transparent material.

10. An image sensor, characterized in that, include: The superlens, filter layer, silicon layer, and circuit layer as described in any one of claims 1 to 9; wherein the superlens, the filter layer, the silicon layer, and the circuit layer are arranged sequentially from top to bottom.

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