Folding and super mixed lens and preparation method thereof

Abstract

The invention provides a refractive-super hybrid lens and a preparation method thereof, and the refractive-super hybrid lens comprises a silicon substrate which is provided with a first surface and a second surface which are opposite to each other; the first surface is a refraction lens surface type and is used for correcting dispersion; a plurality of micro-nano structures are arranged on the first surface or the second surface to form a micro-nano structure array for realizing specific wavefront regulation and control; when the micro-nano structure is arranged on the second surface, the optical central axis of the refraction lens face type array coincides with the optical central axis of the micro-nano structure. The refraction and super hybrid lens adopts monocrystalline silicon as a substrate, and the structure of the refraction and super hybrid lens is a single-sided integrated structure integrating a refraction lens surface type and a micro-nano structure on the same surface of the substrate, or a double-sided discrete structure respectively arranging the refraction lens surface type and the micro-nano structure on the front surface and the rear surface of the substrate. Fusion of refractive optics and diffractive optics is achieved, the problems that a traditional infrared lens is high in cost, large in dispersion, heavy in system and the like are solved, and the infrared lens is suitable for a miniaturized and low-cost optical system of the infrared band.

Description

Technical Field

[0001] This invention relates to the field of optical element technology, and in particular to a hyperrefractive hybrid lens and its fabrication method. Background Technology

[0002] Currently, far-infrared optical systems commonly use chalcogenide materials and germanium (Ge) as lens materials, which faces significant challenges in practical applications. First, the material costs remain high, primarily due to the inclusion of elements such as sulfur (S), selenium (Se), and tellurium (Te). This stems mainly from the complex precision melting process and low yield rate. Second, traditional grinding and polishing processes struggle to achieve subwavelength-scale micro / nano structure fabrication, severely restricting the integration of diffraction elements with traditional refractive lenses. Furthermore, to compensate for aberrations in the infrared band, the system must employ a multi-lens stacking scheme, resulting in a thicker optical module that fails to meet the demands of modern, thinner devices.

[0003] As an emerging micro-nano optical element, superlenses have shown great potential due to their advantages such as low cost, high integration, and miniaturization. However, planar superlens imaging still has obvious drawbacks, specifically, its field of view is small due to limitations of existing etching processes, and it cannot correct large dispersion, making it difficult to meet the needs of practical applications. Summary of the Invention

[0004] Based on this, the present invention provides a super-refractive hybrid lens and its fabrication method. The super-refractive hybrid lens uses single-crystal silicon as the silicon substrate. Its structure is either a single-sided integrated structure integrating a refractive lens surface and micro / nano structures on the same surface of the substrate, or a double-sided discrete structure with refractive lens surface and micro / nano structures respectively disposed on the front and back surfaces of the substrate. This achieves the fusion of refractive and diffractive optics, solving the problems of high cost, large dispersion, and bulky systems associated with traditional infrared lenses. It is particularly suitable for miniaturized, low-cost optical systems in the 3-5μm or 8-14μm infrared band.

[0005] In a first aspect, embodiments of this application provide a hyperrefractive hybrid lens, comprising:

[0006] A silicon substrate having opposing first and second surfaces; the first surface is a refractive lens type for correcting dispersion;

[0007] The first surface or the second surface is provided with multiple micro-nano structures to form a micro-nano structure array for achieving specific wavefront modulation; wherein, when the micro-nano structure is provided on the second surface, the optical central axis of the refractive lens array coincides with the optical central axis of the micro-nano structure.

[0008] Optionally, the refractive lens surface is one of a spherical surface, an aspherical surface, a freeform surface, or an optical surface characterized by a Zernike polynomial; the second surface is one of a plane, a spherical surface, an aspherical surface, or a freeform surface.

[0009] Optionally, the micro / nano structure includes nanocylinders, nanopores, nanoprisms, nanopores, or any array of structures.

[0010] Optionally, the characteristic dimensions of the micro / nano structure cross-section exhibit a gradient distribution, and the gradient change of the characteristic dimensions is positively correlated with the phase modulation amount, satisfying:

[0011] ;

[0012] in, The characteristic dimensions of the cross-section of the micro / nano structure. The change in characteristic size. The wavelength is the center wavelength of the operating band of the superconducting hybrid lens.

[0013] Optionally, the feature size range of the micro / nano structure is 500nm~2500nm, the center distance deviation of the micro / nano structure is less than or equal to 5%, the etching depth-to-width ratio is greater than 20:1, and the sidewall perpendicularity is greater than or equal to 88°.

[0014] Optionally, the operating wavelength of the super-refractive lens is 3μm-5μm or 8μm-14μm; the combined optical parameters of the micro / nano structure and the refractive lens surface shape satisfy the following relationship:

[0015] ;

[0016] in, For focus shift, The wavelength is the center wavelength of the operating band of the superconducting hybrid lens.

[0017] Optionally, the super-refractive hybrid lens also includes:

[0018] An antireflective coating is disposed on the surface of the refractive lens and / or the micro / nano structure;

[0019] The antireflection coating has an antireflection band of 3μm-5μm or 8μm-14μm, an incident angle range of 0-30°, and a reflection loss of less than 2%.

[0020] Based on the same inventive concept, this application also provides a method for fabricating a refractive-hyperrefractory hybrid lens, used to fabricate the refractive-hyperrefractory hybrid lens provided in the first aspect, the fabrication method comprising:

[0021] Provide a double-sided polished silicon substrate and clean its surface;

[0022] A refractive lens profile is formed on the first surface of the silicon substrate;

[0023] Micro-nano structures are fabricated on the first surface or the second surface.

[0024] Optionally, the step of preparing the refractive lens surface includes:

[0025] Photoresist is spin-coated onto the first surface of a silicon substrate, and a smooth photoresist surface is formed by photolithography and thermal reflow processes.

[0026] Using the photoresist surface after thermal reflow as a mask, the morphology of the photoresist surface is transferred to the silicon substrate by inductively coupled plasma etching process to obtain a refractive lens surface.

[0027] Optionally, the surface profile error of the photoresist surface formed by the thermal reflow process is A, and the surface roughness is Ra; the topographic deviation between the etched silicon substrate surface and the preset design surface is B, and the sidewall roughness is Rz, satisfying the following relationship:

[0028] ; ; , ;

[0029] in, The wavelength is the center wavelength of the operating band of the superconducting hybrid lens.

[0030] This invention discloses a super-refractive hybrid lens, comprising a silicon substrate having opposing first and second surfaces. The first surface is a refractive lens profile used to correct dispersion. Multiple micro / nano structures are disposed on either the first or second surface, forming a micro / nano structure array for achieving specific wavefront modulation. When the micro / nano structures are disposed on the second surface, the optical central axis of the refractive lens array coincides with the optical central axis of the micro / nano structures. This super-refractive hybrid lens uses single-crystal silicon as the substrate, and its structure is either a single-sided integrated structure integrating the refractive lens profile and micro / nano structures on the same surface of the substrate, or a double-sided discrete structure with the refractive lens profile and micro / nano structures disposed on the front and back surfaces of the substrate, respectively. It achieves the fusion of refractive and diffractive optics, solving the problems of high cost, large dispersion, and bulky systems associated with traditional infrared lenses. It is particularly suitable for miniaturized, low-cost optical systems in the 3-5μm or 8-14μm infrared band. Attached Figure Description

[0031] Figure 1 These are schematic diagrams of the structures of four types of superconducting hybrid lenses provided in the embodiments of this application;

[0032] Figure 2 The simulation results of the transmittance of the antireflection coating of a superconducting hybrid lens are shown in the example diagram.

[0033] Figure 3 A schematic diagram illustrating a method for fabricating a superconducting hybrid lens as provided in this embodiment;

[0034] Figure 4 A flowchart illustrating the fabrication of a hyperrefractive hybrid lens using semiconductor mass production processes is provided for this embodiment.

[0035] Figure 5 The image shows the white light interferometer results of the photoresist and the etched silicon substrate surface during the fabrication of the superconducting hybrid lens in this embodiment.

[0036] Figure 6 The image shows the SEM and FIB test results of the surface of a superconducting hybrid lens provided for an embodiment.

[0037] Figure 7 This paper compares the phase distribution results of a single lens in the prior art with the phase distribution results of the superconducting hybrid lens provided in this application. Detailed Implementation

[0038] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It is understood that the specific embodiments described herein are merely illustrative of the present application and not intended to limit it. Furthermore, it should be noted that, for ease of description, only the parts relevant to the present application are shown in the drawings, not the entire structure. Various modifications and variations can be made to the present application without departing from its spirit or scope, which will be apparent to those skilled in the art. Therefore, the present application is intended to cover modifications and variations of the present application that fall within the scope of the technical solutions claimed in the corresponding claims and their equivalents. It should be noted that the implementation methods provided in the embodiments of the present application can be combined with each other without contradiction.

[0039] Figure 1 The following are schematic diagrams of the structures of four types of superconducting hybrid lenses provided in the embodiments of this application, with reference to... Figure 1 The refractive-hybrid lens provided in this application embodiment can be applied to an infrared imaging system. The refractive-hybrid lens 1 includes a silicon substrate 10, such as a single-crystal silicon substrate, having opposing first surfaces M1 and second surfaces M2. The first surface M1 is a refractive lens profile used to correct dispersion. Multiple micro / nano structures 11 are disposed on either the first surface M1 or the second surface M2, forming a micro / nano structure array for achieving specific wavefront modulation. Specifically, when the micro / nano structure 11 is disposed on the second surface M2, the optical central axis of the refractive lens array coincides with the optical central axis of the micro / nano structure 11.

[0040] Specifically, the silicon substrate 10 can be made of silicon. The super-hybrid lens 1 mainly includes the following two surface structures.

[0041] The first type is a single-sided integrated structure. Specifically, micro / nano structures 11 and refractive lens surfaces are integrated on the same surface of a silicon substrate.

[0042] Optionally, the refractive lens surface can be a freeform surface, a spherical surface, an aspherical surface, or an optical surface characterized by Zernike polynomials, used to work in conjunction with the micro / nano structure 11 to achieve broadband achromatic aberration. The second surface M2 can be a planar surface, a spherical surface, an aspherical surface, or a freeform surface. The micro / nano structure 11 is composed of subwavelength-scale silicon nanocylinders, nanopores, nanoprisms, nanopores, or arbitrary structure arrays, used to achieve specific wavefront modulation.

[0043] For example, such as Figure 1 As shown in (1), the first surface M1 is a convex surface, and the superconducting hybrid lens provided in this application integrates a micro / nano structure 11 on the convex surface. Figure 1 As shown in (2), the first surface M1 is a concave curved surface, and the micro / nano structure 11 is integrated on the concave curved surface of the superconducting hybrid lens provided in this application. It should be noted that the embodiments of this application... Figure 1 In this example, only the second surface M2 is used as a plane for illustration.

[0044] The second type is a dual-sided discrete structure. Micro / nano structures 11 and refractive lens surfaces are respectively formed on the first surface M1 and the second surface M2 of the silicon substrate 10. For example, as shown... Figure 1 As shown in (3), the first surface M1 is a convex surface, and the second surface M2 is a plane. The convex surface and the micro / nano structure 11 are integrated on both sides of the silicon substrate 10, respectively. Figure 1 As shown in (4), the first surface M1 is a concave curved surface, and the second surface M2 is a planar surface. The concave curved surface and the micro / nano structure 11 are integrated on both sides of the silicon substrate 10, respectively. Among them, the first surface M1 is a refractive curved surface used to correct dispersion, and its surface shape is one of a free-form surface, a sphere, an aspherical surface, or an optical surface shape characterized by Zernike polynomials. The second surface M2 is a refractive super-hybrid lens nanostructure array with phase modulation function. The micro / nano structure 11 includes silicon nanocylinders, nano-circular holes, nano-square pillars, nano-square holes, or arbitrary structure arrays. In this application, the optical central axis of the micro / nano structure array is coincident with the optical central axis of the refractive lens surface shape, thereby optimizing the optical path transmission and improving the imaging quality.

[0045] Optionally, the operating wavelength of the super-refractive hybrid lens 1 is 3μm-5μm or 8μm-14μm. When the super-refractive hybrid lens 1 operates in the 3-5μm or 8-14μm infrared band, the combined optical parameters of the micro / nano structure 11 and the refractive lens surface shape satisfy:

[0046] , (1.1);

[0047] in, For focus shift, This is the center wavelength of the working band of the superconducting hybrid lens.

[0048] Based on the above embodiments, the superconducting hybrid lens further includes an antireflective coating disposed on the surface of the refractive lens surface and / or the micro / nano structure 11. Figure 1 (Not shown in the image). The antireflection coating has an antireflection band of 3μm-5μm or 8μm-14μm, an incident angle range of 0-30°, and a reflection loss of less than 2%.

[0049] Optionally, the antireflective coating can be a multilayer film, which can be formed by alternating MgF2 / Ge deposition, and the film thickness meets the following requirements:

[0050] d=λ0 / 4n, (1.2).

[0051] Where λ0 = 4.2 μm and n is the refractive index of the film, when light with a wavelength range of 8 μm-14 μm is incident at an angle of 0-30°, the reflection loss of the superconducting lens is <2%.

[0052] Based on the above embodiments, refer to Figure 1 Furthermore, some low-refractive-index transparent materials, such as nano-adhesives and encapsulating adhesives, can be filled between the micro- and nano-structures 11. Their refractive indices are lower than those of the micro- and nano-structures 11.

[0053] For example, Figure 2 The simulation results of the transmittance of the antireflection coating of a hybrid lens provided in the embodiment are shown in the figure. Figure 2 This application provides an antireflective coating on the surface of the refractive lens surface and / or micro / nano structure 11. Using the equivalent refractive index method, the antireflective coating structure is calculated to ensure a light transmittance of over 90%, thereby maximizing the optical efficiency of the superconducting refractive index hybrid lens. Specifically, for subwavelength structures and their thin films, the equivalent refractive index calculation method shown in the following formula can be used:

[0054] , (1.3).

[0055] Where, n eff For the equivalent refractive index, n p n represents the refractive index of the micro / nano structure at different wavelengths. b Let f be the refractive index of the filling material at different wavelengths, f be the ratio of the area of ​​the micro / nano structure to the total area under different unit structures, and (1-f) be the ratio of the area of ​​the filling material to the total area under different unit structures. Here, micro / nano structures can also be called nano-unit structures. For nano-unit structures, since the shape and number of each structure are generally different, it is necessary to calculate the equivalent refractive index of each nano-unit structure, and then perform a weighted average to obtain the equivalent refractive index of the overall hyperrefractive hybrid lens. For example... Figure 2 The left image and Figure 2 As shown in the right figure, with the antireflection band of the antireflection film being 3μm-5μm or 8μm-14μm and the incident angle range being 0-30°, the simulation results of the transmittance of the antireflection film of the superconducting lens show that after the antireflection film is coated, the antireflection effect of each nanounit structure at different wavelengths reaches more than 90%, and the reflection loss is less than 2%. Therefore, it can be seen that the superconducting lens has high light transmission efficiency.

[0056] Meanwhile, the embodiments of this application can also further improve the optical parameter performance of the folding super-hybrid lens 1 through simulation optimization design, wherein the simulation optimization conditions are as follows:

[0057] First, the super-hybrid lens 1 was simulated and verified. Specifically, a subwavelength periodic unit model of the super-hybrid lens 1 was established using simulation software. The micro / nano structure 11 was constructed using a nanocylinder or square column array. Electromagnetic field simulations were performed on the micro / nano structure 11, and the structural parameters were optimized to ensure that the phase modulation error of TM / TE polarized light was <λ / 20 in the working wavelength range of 3μm-5μm. Furthermore, four layers of alternating MgF2 / Ge coatings were deposited on the surface of the super-hybrid lens 1, with the film thickness satisfying: d=λ0 / 4n, (1.2). Simulation results show that the reflection loss of light with a center wavelength of 8μm-14μm in the incident angle range of 0-30° is <2%.

[0058] Second, the performance indicators of the folded super-hybrid lens 1 were tested.

[0059] Specifically, the transmittance of a single-cycle unit of the micro / nano structure 11 was tested: under the working wavelength of 3μm-5μm and a transmittance of 92%, the diameter tolerance of the nanocylinder was controlled within ±20nm, and the height tolerance was controlled within ±50nm.

[0060] Third, equivalent refractive index matching test: Adjust the duty cycle of the nanopillars to 0.15-0.85 to achieve the equivalent refractive index n eff =1.8-2.2, so that the average transmittance is >90%, Δn is satisfied. eff / n eff <0.05. Where, Δn eff This represents the equivalent refractive index deviation.

[0061] Based on the above embodiments, the feature dimensions of the cross-section of the micro / nano structure 11 exhibit a gradient distribution, and the gradient change of the feature dimensions is positively correlated with the phase modulation amount, satisfying:

[0062] ;

[0063] in, The characteristic dimensions of the 11 cross-section of the micro / nano structure are... The change in characteristic size. This is the center wavelength of the operating band of the superconducting hybrid lens. For example, refer to... Figure 6 When the micro / nano structure 11 uses nanocylinders or nanopores, the characteristic dimension refers to the diameter of the nanocylinder or nanopore. When the micro / nano structure 11 uses nanocylinders or nanopores, the characteristic dimension refers to the side length of the nanoprism or nanopore.

[0064] Optionally, the feature size range of the micro / nano structure 11 is 500nm~2500nm, the center distance deviation of the micro / nano structure 11 is less than or equal to 5%, the etching aspect ratio is greater than 20:1, and the sidewall perpendicularity is greater than or equal to 88°. By limiting the feature size of the micro / nano structure 11, the transmittance in the 3μm-5μm and 8μm-14μm bands can be improved.

[0065] Based on the same inventive concept, this application also provides a method for fabricating a hyperrefractive hybrid lens. Figure 3 This is a schematic diagram illustrating a method for fabricating a hyperrefractive hybrid lens, as provided in the embodiment. Figure 4 The flowchart provided in this embodiment describes the fabrication of a hyperrefractive hybrid lens using semiconductor mass production processes. Figure 5 The image shows the white light interferometer results of the photoresist and the etched silicon substrate surface during the fabrication of the superconducting hybrid lens in this embodiment. Figure 6 The images shown are SEM and FIB test results of the surface of a hyperrefractive-refractive hybrid lens provided in this embodiment. The fabrication method of the hyperrefractive-refractive hybrid lens provided in this application embodiment is used to fabricate the hyperrefractive-refractive hybrid lens provided in the above embodiment. (Reference) Figures 3-6 As shown, the fabrication method of the super-refractive hybrid lens includes:

[0066] S101. Provide a double-sided polished silicon substrate and clean its surface.

[0067] Specifically, in combination Figure 1 (3) and Figure 1 (4) Taking the preparation of a double-sided discrete structure as an example, the silicon substrate is first pretreated.

[0068] For example, a double-sided polished silicon wafer is used as the optical substrate, and RCA cleaning and oxygen plasma resist removal are performed sequentially to ensure that the surface roughness Ra < 1 nm.

[0069] S102. A refractive lens surface is prepared on the first surface of a silicon substrate.

[0070] Furthermore, a refractive lens surface is fabricated on the first surface M1 of the silicon substrate 10, specifically including the following steps:

[0071] Photoresist is spin-coated onto the first surface of a silicon substrate, and a smooth photoresist surface is formed through photolithography and thermal reflow processes, achieving a curvature radius error of <2%. Using the reflowed photoresist surface as a mask, an etching process is employed to transfer the morphology of the photoresist surface to the silicon substrate, obtaining a refractive lens surface. If an ICP (Inductively Coupled Plasma) etching system is used, the surface shape accuracy PV value is <λ / 10, where λ is the center wavelength of the etching laser in the etching system.

[0072] It should be noted that the fabrication and characterization of the refractive lens surface shape must at least meet the following process quality control indicators:

[0073] First, control of the photoresist morphology during thermal reflow. Positive photoresist, after UV exposure and development, is reflowed within a specific temperature range to form the transition master for the refractive lens. The surface morphology of the photoresist after thermal reflow must meet the following requirements:

[0074] a) The surface profile error of the photoresist surface formed by the thermal reflow process is A, where A ≤ λ / 10. Here, λ is the center wavelength of the working band of the superconducting hybrid lens.

[0075] b) Surface roughness is Ra, Ra≤20nm.

[0076] Second, the reproducibility of the etched morphology on the silicon substrate. Using a hot-reflow photoresist as a mask, deep silicon reactive ion etching was performed using the Bosch process, with an etching selectivity ratio ≥20:1. The silicon substrate surface after etching must meet the following requirements:

[0077] a) The morphological deviation between the etched silicon substrate surface and the designed surface is B, where B≤5%. Specifically, this can be detected by three-dimensional comparison using a white light interferometer and a folded super-hybrid lens.

[0078] b) The sidewall roughness is Rz. Specifically, the cross-section of the folded hybrid lens can be measured using a scanning electron microscope.

[0079] c) The difference between the substrate roughness Ra and the photoresist master is controlled within ±5%.

[0080] S103. Fabricate micro / nano structures on the first or second surface.

[0081] For details, please refer to Figure 1 (1) and Figure 1 (2) When micro-nano structures are fabricated on the first surface, a single-sided integrated structure is formed.

[0082] refer to Figure 1 (3) and Figure 1 (4) When micro-nano structures are fabricated on the second surface, a two-sided discrete structure is formed.

[0083] For example, taking the fabrication of a double-sided discrete structure as an example, an infrared alignment system is used to etch both sides of the silicon substrate, controlling the alignment error to <500nm. Simultaneously, multiple micro / nano structures are etched on the second surface M2 to form a micro / nano structure array, with feature sizes ranging from 500 nm to 2500 nm. Using Bosch technology, subwavelength structure etching with an aspect ratio greater than 20:1 is achieved, with sidewall perpendicularity deviation <1°.

[0084] As an example, combined Figure 1 (3) Figure 1 (4) and Figure 4 Taking the mass production process of hybrid lenses based on double-sided alignment semiconductor technology as an example, the specific process flow includes:

[0085] Step S1, Photolithography: Photoresist is spin-coated onto one surface of a silicon substrate, and a smooth photoresist surface is formed through photolithography and thermal reflow processes. For example, high-precision photoresist is spin-coated onto a silicon substrate, and a curved surface mask is exposed using a stepper lithography machine (365nm center wavelength).

[0086] Step S2, Development: Develop with 2.38% tetramethylammonium hydroxide (TMAH) solution to form a colloidal pattern on the curved surface.

[0087] Step S3, Thermal Reflow: Under nitrogen protection, heat to 200°C at a rate of 5°C / min, hold for 30 minutes, then cool to melt the photoresist and form a smooth curved surface, such as... Figure 5 As shown in (1).

[0088] Step S4, Etching: The curved surface is transferred to the silicon substrate using deep reactive ion etching (DRIE), with an etching depth of 50μm-100μm and a sidewall perpendicularity >88°. Figure 5 As shown in (2), the difference between the etched surface and the photolithographic reflow surface is compared. Figure 5 As shown in (3), the error does not exceed 2 micrometers, which is in line with the optical lens specifications.

[0089] Step S5: Apply protective layer: Spin-coat a PMMA / silicone fluoride (1:3 mass ratio) mixed solution and cure at 200℃ to form a 200nm protective layer.

[0090] Step S6, Alignment Lithography: Using an infrared alignment system (accuracy ±0.5μm), expose a superlens phase mask on the other side of the silicon substrate.

[0091] Step S7, Secondary Etching: The metasurface array is prepared using a low-damage etching process (ICP power 200W, SF4 flow rate 20sccm).

[0092] Figure 6The following are SEM and FIB test results of the surface of a hyperrefractive hybrid lens provided as an example, wherein... Figure 6 (1) and Figure 6 (2) SEM images of the micro / nano structures at feature sizes of 600 nm and 2500 nm. Figure 6 (3) and Figure 6 (4) FIB screenshots of micro / nano structures with feature sizes of 600 nm and 2500 nm. For example... Figure 6 As shown, the micro / nano structure morphology was obtained using scanning electron microscopy (SEM) and focused ion beam (FIB). SEM revealed that circular apertures of 700 nm and 1500 nm could coexist on the same wafer. After FIB dicing, the etching depths were 9.6 μm and 14.4 μm, respectively.

[0093] Specifically, when the micro / nano structure 11 uses nanocylinders and nanopores, the array of pores in the micro / nano structure 11 satisfies the following characterization parameters:

[0094] (1) Micro / nano structure morphology. Reference Figure 6 (1) and Figure 6 (2) Under scanning electron microscopy (SEM) observation, the feature sizes exhibit a gradient distribution, ranging from 500 nm to 2500 nm; the array period is constant at 3 μm, and the center-to-center distance deviation of the circular apertures is ≤5%. (Reference) Figure 6 (3) and Figure 6 (4) The longitudinal etching depth of the micro-nano structure is 10 μm ± 0.5 μm and the sidewall verticality is ≥ 88°, as shown by focused ion beam (FIB) profile observation.

[0095] (2) Optical performance related parameters. When the micro / nano structure uses nanocylinders or nanopores, the change in characteristic size gradient is positively correlated with the phase modulation amount, satisfying the following conditions: . This represents the change in diameter. The center wavelength is .

[0096] In the 8μm-14μm working band, the diffraction efficiency of the circular aperture array is ≥75%, the transmittance is ≥70%, and the phase deviation caused by etching depth error is ≤λ / 10.

[0097] Step S8: Clean the protective layer: Remove the residual protective layer in oxygen plasma (power 100W, time 120 seconds) while preserving the integrity of the superlens structure.

[0098] Step S9, Cutting: Use high-precision laser cutting equipment for subsequent cutting and sorting to obtain multiple independent superconducting hybrid lenses.

[0099] The above steps together constitute a complete process flow for mass production of superconducting hybrid lenses based on double-sided alignment semiconductor technology, ensuring high product quality and consistency.

[0100] Figure 7 A comparison is made between the phase distribution results of a single lens in the prior art and the phase distribution results of the superconducting hybrid lens provided in this application, wherein... Figure 7 The left figure shows the phase compensation curve in the prior art without the addition of silicon curved surfaces. Figure 7 The right figure in the figure shows the compensation phase curve of the super-refractive hybrid lens provided in the embodiment of this application after adding the refractive lens surface and micro / nano structure.

[0101] like Figure 7 As shown, the embodiments of this application obtain a super-hybrid lens by performing a hybrid design of refractive lens surface shape and micro / nano structure on a silicon substrate. The phase dispersion of 200 radians is fully compensated, which further increases the degree of freedom in optical lens design.

[0102] In summary, the hybrid refractive-superlens lens obtained using the fabrication method provided in this application has the optical performance advantages of combining the small size, light weight, and low cost of a superlens with the integration of the curved surface of a refractive lens to compensate for the poor achromatic ability of the superlens. The dispersion correction capability of the hybrid refractive-superlens lens is quantified by the phase modulation efficiency, especially in the 8μm-14μm band, improving the dispersion deviation of a single superlens from 10rad to 200rad. Therefore, phase consistency is achieved in the far-infrared band, and it has extremely high application prospects in the 3μm-5μm or 8-14μm infrared bands.

[0103] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein. Features of various embodiments of the present invention can be partially or wholly coupled or combined with each other, and can cooperate and be technically driven in various ways. Various obvious changes, readjustments, combinations, and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments. Many other equivalent embodiments may be included without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A superconducting hybrid lens, characterized in that, include: A silicon substrate having opposing first and second surfaces; the first surface is a refractive lens type for correcting dispersion; The first surface or the second surface is provided with multiple micro-nano structures to form a micro-nano structure array for achieving specific wavefront modulation; wherein, when the micro-nano structure is provided on the second surface, the optical central axis of the refractive lens array coincides with the optical central axis of the micro-nano structure.

2. The superconducting hybrid lens according to claim 1, characterized in that, The refractive lens surface is one of a spherical surface, an aspherical surface, a freeform surface, or an optical surface characterized by a Zernike polynomial; the second surface is one of a plane, a spherical surface, an aspherical surface, or a freeform surface.

3. The superconducting hybrid lens according to claim 1, characterized in that, The micro / nano structures include nanocylinders, nanopores, nanoprisms, nanopores, or arbitrary arrays.

4. The superconducting hybrid lens according to claim 1, characterized in that, The characteristic dimensions of the micro / nano structure cross-section exhibit a gradient distribution, and the gradient change of these characteristic dimensions is positively correlated with the phase modulation amount, satisfying the following relationship: ； in, The characteristic dimensions of the cross-section of the micro / nano structure. The change in characteristic size. The wavelength is the center wavelength of the operating band of the superconducting hybrid lens.

5. The superconducting hybrid lens according to claim 1, characterized in that, The micro / nano structure has a feature size range of 500nm to 2500nm, a center distance deviation of less than or equal to 5%, an etching aspect ratio greater than 20:1, and a sidewall perpendicularity greater than or equal to 88°.

6. The superconducting hybrid lens according to claim 1, characterized in that, The operating wavelength of the super-refractive hybrid lens is 3μm-5μm or 8μm-14μm; the combined optical parameters of the micro / nano structure and the refractive lens surface shape satisfy the following: ； in, For focus shift, The wavelength is the center wavelength of the operating band of the superconducting hybrid lens.

7. The superconducting hybrid lens according to claim 6, characterized in that, Also includes: An antireflective coating is disposed on the surface of the refractive lens and / or the micro / nano structure; The antireflection coating has an antireflection band of 3μm-5μm or 8μm-14μm, an incident angle range of 0-30°, and a reflection loss of less than 2%.

8. A method for preparing a refractive-hyperrefractory hybrid lens, used to prepare the refractive-hyperrefractory hybrid lens according to any one of claims 1-6, characterized in that, The preparation method includes: Provide a double-sided polished silicon substrate and clean its surface; A refractive lens profile is formed on the first surface of the silicon substrate; Micro-nano structures are fabricated on the first surface or the second surface.

9. The preparation method according to claim 8, characterized in that, The steps for preparing the refractive lens surface shape include: Photoresist is spin-coated onto the first surface of a silicon substrate, and a smooth photoresist surface is formed by photolithography and thermal reflow processes. Using the photoresist surface after thermal reflow as a mask, the morphology of the photoresist surface is transferred to the silicon substrate by inductively coupled plasma etching process to obtain a refractive lens surface.

10. The preparation method according to claim 9, characterized in that, The surface profile error of the photoresist surface formed by the hot reflow process is A, and the surface roughness is Ra; the topographic deviation between the etched silicon substrate surface and the preset design surface is B, and the sidewall roughness is Rz, satisfying the following relationship: ； ； ， ； in, The wavelength is the center wavelength of the operating band of the superconducting hybrid lens.

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