An adjustable metalens and a preparation method and application thereof

Abstract

The application provides a tunable superlens and a preparation method and application thereof, and comprises a first substrate and a second substrate; the first substrate comprises a cylindrical support body, the cylindrical support body is open at both ends and extends along a first direction, and a main body structure is arranged in the cylindrical support body; the main body structure comprises a conductive layer, a main body insulating layer and a piezoelectric layer along the first direction, and the main body structure is divided into a first cantilever beam, a center structure and a second cantilever beam along a second direction; the main body insulating layer of the center structure is provided with a first nano column array; one end of the first cantilever beam is connected to an inner wall on one side of the cylindrical support body, and one end of the second cantilever beam is connected to an inner wall on the opposite side; the conductive layer in the main body structure and part of the cylindrical support body form a back cavity; the second substrate is provided with a second nano column array, one end of the second nano column array is exposed to the top surface of the second substrate, and the other end is located in the second substrate; and the edge of the top surface of the second substrate is bonded and connected to the open end surface of the cylindrical support body with the back cavity.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor technology and relates to a tunable superlens, its preparation method, and its application. Background Technology

[0002] Traditional lenses are relatively thick, prompting researchers to propose superlenses to reduce their thickness. A superlens is a thin, compact, and versatile planar lens. By controlling subwavelength nanostructures, superlenses can precisely manipulate the wavefront of light, achieving the focusing function of a lens. These nanostructure-based superlenses are tens of thousands of times thinner than traditional lenses, offering revolutionary guidance for the integration of optical devices.

[0003] The nanostructure of existing superlenses is fixed, which makes the refractive index of the superlens fixed. This makes it impossible for superlenses to achieve precise control of light sources of different wavelengths.

[0004] Therefore, there is an urgent need to provide a superlens that can achieve precise control of light sources of different wavelengths. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a tunable superlens, its fabrication method, and its applications. The superlens provided by this invention features an adjustable nanopillar geometry, thus meeting focusing requirements at different wavelengths and enabling precise control of light sources of varying wavelengths.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a tunable superlens, the tunable superlens comprising a first substrate and a second substrate; the first substrate comprising a cylindrical support having openings at both ends and extending along a first direction, the cylindrical support having a main structure disposed therein; the main structure comprising, along the first direction, a conductive layer, a main insulating layer, and a piezoelectric layer stacked sequentially, the main structure being divided along a second direction perpendicular to the first direction into a first cantilever beam, a central structure, and a second cantilever beam connected sequentially; a first nanopillar array disposed in the main insulating layer of the central structure; one inner wall of the cylindrical support being connected to the end of the first cantilever beam away from the central structure, and the opposite inner wall being connected to the end of the second cantilever beam away from the central structure; the conductive layer in the main structure and a portion of the cylindrical support forming a back cavity; a second nanopillar array disposed in the second substrate, one end of the second nanopillar array being exposed on the top surface of the second substrate, and the other end being located within the second substrate; the exposed end face of the second nanopillar array being flush with the top surface of the second substrate; the edge of the top surface of the second substrate being bonded to the open end face of the cylindrical support having the back cavity.

[0008] It should be noted that the main structure is divided into a first cantilever beam, a central structure and a second cantilever beam along the second direction, which means that the conductive layer, the main insulating layer and the piezoelectric layer in the main structure are each divided into three parts, belonging to the first cantilever beam, the central structure and the second cantilever beam respectively.

[0009] This invention provides an adjustable superlens comprising a first cantilever beam, a second cantilever beam, and a piezoelectric layer. The first and second cantilever beams function similarly to springs. When an electric field is applied to the conductive layer in the main structure, an electrostatic force is generated between the first and second cantilever beams, allowing them to move in a second direction. This, in turn, moves the first nanopillar array in the central structure in the second direction. Simultaneously, when an electric field is applied to the piezoelectric layer in the main structure, mechanical stress is generated, which in turn applies stress to the insulating layer, thereby causing the first nanopillar array to move in the first direction. In summary, the first nanopillar array of this invention can move in both the first and second directions; that is, the nanopillar geometry formed by the first and second nanopillar arrays is adjustable. Therefore, the superlens provided by this invention can meet the focusing requirements at different wavelengths, thereby achieving precise control of light sources of different wavelengths.

[0010] Compared to traditional lenses, the superlens provided by this invention has a significantly reduced thickness, which is beneficial for the integration of optical devices.

[0011] The present invention does not limit the cross-sectional shape of the nanopillars in the first nanopillar array and the second nanopillar array, including but not limited to circular, annular or polygonal (such as square) shapes.

[0012] Preferably, in the main structure, the conductive layer, the main insulating layer, and the piezoelectric layer are all the same in shape and size.

[0013] Preferably, in the main structure, the conductive layer is made of silicon material doped with phosphorus and / or boron.

[0014] In the conductive layer of the present invention, the silicon material doped with phosphorus and / or boron elements includes, but is not limited to, monocrystalline silicon or polycrystalline silicon.

[0015] Preferably, in the main structure, the thickness of the conductive layer is 0.5μm-4μm, for example, it can be 0.5μm, 0.7μm, 0.9μm, 1μm, 1.5μm, 2μm, 2.5μm, 3μm, 3.5μm or 4μm, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0016] Preferably, in the main structure, the material of the main insulating layer includes silicon dioxide.

[0017] Preferably, in the main structure, the thickness of the main insulating layer is 120nm-11μm, for example, it can be 120nm, 150nm, 200nm, 500nm, 800nm, 1000nm, 2μm, 3μm, 5μm, 6μm, 8μm, 9μm or 11μm, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0018] Preferably, in the main structure, the piezoelectric layer is made of indium tin oxide and / or aluminum nitride.

[0019] Preferably, in the main structure, the thickness of the piezoelectric layer is 100nm-3μm, for example, it can be 100nm, 200nm, 500nm, 800nm, 1000nm, 1.5μm, 2μm, 2.5μm or 3μm, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0020] Preferably, both the first cantilever beam and the second cantilever beam have a U-shaped structure and their openings face opposite directions.

[0021] Preferably, the main insulating layer in the central structure is divided into a first insulating thin layer, a second insulating thin layer and a third insulating thin layer along the first direction; the second insulating thin layer is provided with the first nanopillar array, the height direction of the first nanopillar array is parallel to the first direction, and the height of the first nanopillar array is the same as the thickness of the second insulating thin layer.

[0022] Preferably, the thickness of the first insulating layer is 100nm-3μm, for example, it can be 100nm, 200nm, 500nm, 800nm, 1000nm, 1.5μm, 2μm, 2.5μm or 3μm, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0023] Preferably, the thickness of the third insulating layer is 10nm-3μm, for example, it can be 10nm, 20nm, 50nm, 80nm, 100nm, 200nm, 500nm, 800nm, 1000nm, 1.5μm, 2μm, 2.5μm or 3μm, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0024] Preferably, the material of the first nanopillar array includes at least one of polycrystalline silicon, silicon nitride, amorphous silicon, and titanium dioxide.

[0025] Preferably, the height of the first nanopillar array is 10nm-5μm, for example, it can be 10nm, 20nm, 50nm, 80nm, 100nm, 200nm, 500nm, 800nm, 1000nm, 1.5μm, 2μm, 2.5μm, 3μm, 3.5μm, 4μm, 4.5μm or 5μm, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0026] Preferably, in the first nanopillar array, the width of a single nanopillar is 5nm-800nm, for example, it can be 5nm, 8nm, 10nm, 20nm, 50nm, 60nm, 80nm, 100nm, 110nm, 150nm, 200nm, 250nm, 260nm, 300nm, 350nm, 400nm, 450nm, 500nm, 550nm, 600nm, 700nm, 750nm or 800nm, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0027] In the first nanopillar array of the present invention, the width of a single nanopillar refers to the maximum width of the nanopillar. For example, when the cross-section of the nanopillar is circular, the width can also be referred to as the diameter. The rest are similar.

[0028] Preferably, the first nanopillar array comprises multiple structural units, each of which contains nanopillars with different widths.

[0029] Preferably, in the first nanopillar array, the gap between adjacent nanopillars is 10nm-500nm, for example, it can be 10nm, 20nm, 50nm, 100nm, 150nm, 200nm, 250nm, 300nm, 350nm, 400nm, 450nm or 500nm, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0030] Preferably, the cylindrical support is a straight cylindrical structure.

[0031] Preferably, the cylindrical support includes, along the first direction, an insulating base layer, a supporting conductive layer, and a supporting insulating layer stacked sequentially. A first metal lead and a second metal lead are embedded on the side of the supporting insulating layer near the supporting conductive layer, and the first and second metal leads are electrically connected to the conductive layers of the first and second cantilever beams, respectively. A third metal lead and a fourth metal lead are disposed on the side of the supporting insulating layer away from the supporting conductive layer, and the third and fourth metal leads are electrically connected to the piezoelectric layers of the first and second cantilever beams, respectively. The conductive layer in the main structure, together with the supporting conductive layer and the insulating base layer in the cylindrical support, forms a back cavity.

[0032] Preferably, in the cylindrical support, the insulating substrate layer includes a base layer and a base insulating layer stacked sequentially along the first direction, and the side of the base layer away from the base insulating layer is bonded to the top edge of the second substrate.

[0033] Preferably, the material used for the underlayer includes silicon.

[0034] In the underlying material of this invention, silicon materials include, but are not limited to, monocrystalline silicon or polycrystalline silicon.

[0035] Preferably, the thickness of the underlayer is 10μm-775μm, for example, it can be 10μm, 20μm, 50μm, 80μm, 100μm, 150μm, 200μm, 300μm, 400μm, 500μm, 600μm, 700μm or 775μm, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0036] Preferably, the material of the base insulating layer includes silicon dioxide.

[0037] Preferably, the thickness of the base insulating layer is 0.1μm-2μm, for example, it can be 0.1μm, 0.2μm, 0.5μm, 1μm, 1.2μm, 1.5μm, 1.8μm or 2μm, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0038] Preferably, the material of the supporting conductive layer includes silicon material doped with phosphorus and / or boron.

[0039] Preferably, the thickness of the supporting conductive layer is 0.5μm-4μm, for example, it can be 0.5μm, 0.6μm, 0.8μm, 1μm, 1.5μm, 2μm, 2.5μm, 3μm, 3.5μm or 4μm, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0040] Preferably, the conductive support layer in the cylindrical support body and the conductive layer in the main structure are connected on the same plane and have the same thickness.

[0041] Preferably, the material of the supporting insulating layer includes silicon dioxide.

[0042] Preferably, the thickness of the supporting insulating layer is 120nm-11μm, for example, it can be 120nm, 150nm, 200nm, 500nm, 800nm, 1000nm, 2μm, 3μm, 5μm, 6μm, 8μm, 9μm or 11μm, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0043] Preferably, the supporting insulation layer in the cylindrical support body and the main insulation layer in the main structure are connected on the same plane and have the same thickness.

[0044] Preferably, the portion of the cylindrical support body connected to the first cantilever beam is provided with the first metal lead and the third metal lead; the portion of the cylindrical support body connected to the second cantilever beam is provided with the second metal lead and the fourth metal lead.

[0045] Preferably, the first metal lead, the second metal lead, the third metal lead, and the fourth metal lead are all made of conductive metals, such as aluminum.

[0046] Preferably, the thickness of the first metal lead and the second metal lead is independently between 100nm and 3μm, for example, it can be 100nm, 200nm, 500nm, 800nm, 1000nm, 1.5μm, 2μm, 2.5μm or 3μm, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0047] Preferably, the thickness of the third metal lead and the fourth metal lead is independently between 100nm and 3μm, for example, it can be 100nm, 200nm, 500nm, 800nm, 1000nm, 1.5μm, 2μm, 2.5μm or 3μm, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0048] Preferably, the adjustable superlens further includes an electric field control component, which is electrically connected to the first metal lead, the second metal lead, the third metal lead, and the fourth metal lead.

[0049] Preferably, the electric field control component includes a first voltage controller and a second voltage controller, wherein the first voltage controller is electrically connected to a first metal lead and a second metal lead, and the second voltage controller is electrically connected to a third metal lead and a fourth metal lead.

[0050] In this invention, an electric field is applied to the conductive layer in the main structure via a first voltage controller, a first metal lead, and a second metal lead. Adjusting the voltage of the first voltage controller allows the first nanopillar array to move in a second direction. Similarly, an electric field is applied to the piezoelectric layer in the main structure via a second voltage controller, a third metal lead, and a fourth metal lead. Adjusting the voltage of the second voltage controller allows the first nanopillar array to move in a first direction.

[0051] Preferably, the voltage range of the first voltage controller is 0-5V.

[0052] Preferably, the voltage range of the second voltage controller is 0-5V.

[0053] Preferably, the material of the second substrate includes any one of silicon, glass, or quartz.

[0054] Preferably, the thickness of the second substrate is 100μm-900μm, for example, it can be 100μm, 200μm, 300μm, 400μm, 500μm, 600μm, 700μm, 800μm or 900μm, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0055] Preferably, the material of the second nanopillar array includes at least one of polycrystalline silicon, silicon nitride, amorphous silicon, and titanium dioxide.

[0056] Preferably, the height direction of the second nanopillar array is parallel to the first direction, and one end of the second nanopillar array in the height direction is exposed to the top surface of the second substrate.

[0057] Preferably, the height of the second nanopillar array is 10nm-5μm, for example, it can be 10nm, 20nm, 50nm, 80nm, 100nm, 200nm, 500nm, 800nm, 1000nm, 1.5μm, 2μm, 2.5μm, 3μm, 3.5μm, 4μm, 4.5μm or 5μm, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0058] Preferably, in the second nanopillar array, the width of a single nanopillar is 10nm-800nm, for example, it can be 10nm, 20nm, 50nm, 60nm, 80nm, 100nm, 110nm, 150nm, 200nm, 250nm, 260nm, 300nm, 350nm, 400nm, 450nm, 500nm, 600nm, 700nm or 800nm, etc., but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0059] Preferably, the second nanopillar array comprises multiple structural units, each of which contains nanopillars with different widths.

[0060] Preferably, in the second nanopillar array, the distance between adjacent nanopillars is 100nm-500nm, for example, it can be 100nm, 150nm, 200nm, 250nm, 300nm, 350nm, 400nm, 450nm or 500nm, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0061] In a second aspect, the present invention provides a method for fabricating an adjustable superlens as described in the first aspect, the method comprising the following steps:

[0062] (1) Preparation of the first substrate:

[0063] A. A substrate is provided, the substrate comprising an insulating front layer and a conductive front layer stacked sequentially;

[0064] A first metal conductive film is deposited on the surface of the conductive front layer side of the substrate, and a first metal lead and a second metal lead are formed after photolithography and etching.

[0065] B. A first insulating film is deposited on the conductive front layer surface after step A, such that the height of the first insulating film is the same as that of the first metal lead and the second metal lead. Then, a nanopillar array precursor layer is deposited on the plane composed of the first metal lead, the second metal lead and the first insulating film. After photolithography and etching, the first nanopillar array is formed.

[0066] C. Fill the spaces between the first nanopillar arrays with a second insulating film, such that the second insulating film covers the first nanopillar arrays;

[0067] D. A second metal conductive film is deposited on the second insulating film, and a third metal lead and a fourth metal lead are formed after photolithography and etching;

[0068] E. A piezoelectric film is deposited on the surface of the second insulating film after step D, such that the height of the piezoelectric film is the same as that of the third and fourth metal leads. Then, the obtained structure is subjected to photolithography and etching to form the first substrate.

[0069] The first substrate includes a cylindrical support with openings at both ends and extending along a first direction. A main structure is disposed within the cylindrical support. The main structure includes a conductive layer, a main insulating layer, and a piezoelectric layer stacked sequentially along the first direction. The main structure is divided into a first cantilever beam, a central structure, and a second cantilever beam connected sequentially along a second direction perpendicular to the first direction. A first nanopillar array is disposed in the main insulating layer of the central structure.

[0070] One inner wall of the cylindrical support is connected to the end of the first cantilever beam away from the central structure, and the opposite inner wall is connected to the end of the second cantilever beam away from the central structure; the conductive layer in the main structure and part of the cylindrical support form a back cavity.

[0071] (2) Fabrication of the second substrate:

[0072] Another substrate is provided, and one side of the substrate is etched into a nanopore array using photolithography and etching processes. Then, nanopillar material is filled into the nanopore array to form a second nanopillar array, resulting in a second substrate.

[0073] One end of the second nanopillar array is exposed on the top surface of the second substrate, and the other end is located in the second substrate; the exposed end face of the second nanopillar array is flush with the top surface of the second substrate;

[0074] (3) The first substrate and the second substrate are bonded together such that the top edge of the second substrate is bonded to the open end face of the cylindrical support having a back cavity, thereby obtaining the adjustable superlens.

[0075] In step E of this invention, the first cantilever beam, the second cantilever beam, and the back cavity structure can be formed by photolithography and etching processes.

[0076] Preferably, the deposition methods for the first conductive metal film, the first insulating film, the nanopillar array precursor layer, the second insulating film, the second conductive metal film, and the piezoelectric film independently include any one or a combination of at least two of physical vapor deposition, chemical vapor deposition, or atomic layer deposition.

[0077] Preferably, the filling method of the nanopillar material includes any one or a combination of at least two of physical vapor deposition, chemical vapor deposition, or atomic layer deposition.

[0078] Thirdly, the present invention provides an optical device, which includes the tunable superlens described in the first aspect, or the tunable superlens prepared by the preparation method described in the second aspect.

[0079] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0080] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0081] (1) This invention provides an adjustable superlens, which is provided with a first cantilever beam, a second cantilever beam, and a piezoelectric layer. The first and second cantilever beams function similarly to springs. When an electric field is applied to the conductive layer in the main structure, an electrostatic force is generated between the first and second cantilever beams, which can move the first and second cantilever beams in the second direction, thereby driving the first nanopillar array in the central structure to move in the second direction. At the same time, when an electric field is applied to the piezoelectric layer in the main structure, the piezoelectric layer generates mechanical stress, which applies stress to the main insulating layer, thereby causing the first nanopillar array to move in the first direction. In summary, the first nanopillar array of this invention can move in the first and second directions. That is, the nanopillar geometry structure composed of the first and second nanopillar arrays is adjustable. Therefore, the superlens provided by this invention can meet the focusing requirements at different wavelengths, thereby achieving precise control of light sources of different wavelengths.

[0082] (2) Compared with traditional lenses, the thickness of the super lens provided by the present invention is greatly reduced, which is beneficial to the integration of optical devices. Attached Figure Description

[0083] Figure 1 This is a frontal cross-sectional view of the first substrate in Embodiments 1-3 of the present invention.

[0084] Figure 2 This is a top view of the first substrate in Embodiments 1-3 of the present invention.

[0085] Figure 3 This is a top cross-sectional view of the first substrate in Embodiments 1-3 of the present invention.

[0086] Figure 4 This is a partially enlarged cross-sectional schematic diagram of the first substrate in Embodiments 1-3 of the present invention.

[0087] Figure 5 This is a schematic diagram of the structure of the superlens provided in Embodiments 1-3 of the present invention.

[0088] Figure 6This is a schematic diagram of the process for preparing the first substrate in Embodiments 1-3 of the present invention.

[0089] Figure 7 This is a schematic diagram of the process for preparing the second substrate in Examples 1-3 of the present invention.

[0090] Wherein, 1-cylindrical support; 101-bottom layer; 102-bottom insulating layer; 103-supporting conductive layer; 104-supporting insulating layer; 2-conductive layer; 3-main insulating layer; 301-first nanopillar array; 4-piezoelectric layer; 5-first cantilever beam; 6-second cantilever beam; 7-central structure; 8-first metal lead; 9-second metal lead; 10-third metal lead; 11-fourth metal lead; 12-second nanopillar array. Detailed Implementation

[0091] It should be understood that in the description of this invention, the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0092] It should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "set," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0093] The technical solution of the present invention will be further illustrated below through specific embodiments.

[0094] Example 1

[0095] This embodiment provides an adjustable superlens, which includes a first substrate, a second substrate, a first voltage controller, and a second voltage controller.

[0096] like Figure 1 As shown, the first substrate includes a cylindrical support 1, which has openings at both ends and extends along a first direction. A main structure is disposed within the cylindrical support 1. The main structure includes, along the first direction, a conductive layer 2, a main insulating layer 3, and a piezoelectric layer 4 stacked sequentially. The conductive layer 2, the main insulating layer 3, and the piezoelectric layer 4 have the same shape and size. The conductive layer 2 is made of phosphorus-doped silicon, and the phosphorus doping amount in the conductive layer 2 is 5 × 10⁻⁶. 5 cm -3 The thickness is 2μm; the main insulating layer 3 is made of silicon dioxide and has a thickness of 5μm; the piezoelectric layer 4 is made of indium tin oxide (ITO) and has a thickness of 1.5μm; the main structure is divided along a second direction perpendicular to the first direction into a first cantilever beam 5, a central structure 7, and a second cantilever beam 6 connected in sequence. Both the first cantilever beam 5 and the second cantilever beam 6 are Z-shaped structures with openings facing opposite directions, such as... Figure 2 As shown.

[0097] The main insulating layer 3 in the central structure 7 is sequentially divided into a first insulating thin layer, a second insulating thin layer, and a third insulating thin layer along the first direction. The thickness of the first insulating thin layer is 1 μm, and the thickness of the third insulating thin layer is 1 μm. A first nanopillar array 301 is disposed in the second insulating thin layer. The height direction of the first nanopillar array 301 is parallel to the first direction, and the height of the first nanopillar array 301 is the same as the thickness of the second insulating thin layer. The first nanopillar array 301 is distributed in an array shape, and the material is polycrystalline silicon. The height of the first nanopillar array 301 is 3 μm, the cross-section of each nanopillar is square, and the gap between adjacent nanopillars is 250 nm. The first nanopillar array 301 includes multiple structural units, and the width of the nanopillars in each structural unit is different, ranging from 5 nm to 800 nm.

[0098] The cylindrical support 1 is a straight cylindrical structure; one inner wall of the cylindrical support 1 is connected to the end of the first cantilever beam 5 away from the central structure 7, and the opposite inner wall is connected to the end of the second cantilever beam 6 away from the central structure 7; as Figure 1 As shown, the cylindrical support 1 includes, along the first direction, a bottom layer 101, a bottom insulating layer 102, a supporting conductive layer 103, and a supporting insulating layer 104 stacked sequentially. The bottom layer 101 is made of silicon and has a thickness of 350 μm; the bottom insulating layer 102 is made of silicon dioxide and has a thickness of 1 μm; the supporting conductive layer 103 and the main structure conductive layer 2 have the same material and thickness, and the supporting conductive layer 103 and the main structure conductive layer 2 are connected on the same plane; the supporting insulating layer 104 and the main insulating layer 3 have the same material and thickness, and the supporting insulating layer 104 and the main insulating layer 3 are connected on the same plane.

[0099] like Figure 1 , Figure 3 and Figure 4 As shown, a first metal lead 8 and a second metal lead 9 are embedded on the side of the supporting insulating layer 104 near the supporting conductive layer 103. The first metal lead 8 and the second metal lead 9 are made of aluminum metal, and their thicknesses are the same as the thickness of the first insulating thin layer. The first metal lead 8 and the second metal lead 9 are electrically connected to the conductive layer 2 of the first cantilever beam 5 and the conductive layer 2 of the second cantilever beam 6, respectively, and are also electrically connected to the first voltage controller. The voltage range of the first voltage controller is 0-5V.

[0100] like Figure 1 , Figure 2 and Figure 4 As shown, a third metal lead 10 and a fourth metal lead 11 are provided on the side of the supporting insulating layer 104 away from the supporting conductive layer 103. The material of the third metal lead 10 and the fourth metal lead 11 is aluminum, and the thickness of the third metal lead 10 and the fourth metal lead 11 is the same as the thickness of the piezoelectric layer 4. The third metal lead 10 and the fourth metal lead 11 are electrically connected to the piezoelectric layer 4 of the first cantilever beam 5 and the piezoelectric layer 4 of the second cantilever beam 6 respectively, and the third metal lead 10 and the fourth metal lead 11 are electrically connected to the second voltage controller; the voltage range of the second voltage controller is 0-5V.

[0101] The first metal lead 8 and the third metal lead 10 are located in the part where the cylindrical support 1 is connected to the first cantilever beam 5; the second metal lead 9 and the fourth metal lead 11 are located in the part where the cylindrical support 1 is connected to the second cantilever beam 6; the conductive layer 2 in the main structure, together with the supporting conductive layer 103, the bottom insulating layer 102 and the bottom layer 101 in the cylindrical support 1, form a back cavity;

[0102] The second substrate contains a second nanopillar array 12, the height direction of which is parallel to the first direction. One end of the second nanopillar array 12 in the height direction is exposed on the top surface of the second substrate, and the other end is located in the second substrate. The exposed end face of the second nanopillar array 12 is flush with the top surface of the second substrate. The second substrate is made of glass with a thickness of 450 μm. The second nanopillar array 12 is arranged in an array and is made of polycrystalline silicon. The height of the second nanopillar array 12 is 3 μm, the cross-section of each nanopillar is square, and the distance between adjacent nanopillars is 300 nm. The second nanopillar array 12 includes multiple structural units, and the width of the nanopillars in each structural unit is different, ranging from 10 nm to 800 nm.

[0103] The top edge of the second substrate is bonded to the side of the bottom layer 101 of the cylindrical support 1 away from the bottom insulating layer 102, such as... Figure 5 As shown.

[0104] This embodiment also provides a method for fabricating the above-mentioned tunable superlens, the method comprising the following steps:

[0105] (1) The first substrate is prepared, and the preparation process is as follows: Figure 6 As shown:

[0106] S1. Provide an SOI silicon wafer, which consists of a silicon layer, a silicon dioxide layer and a phosphorus-doped silicon layer stacked sequentially.

[0107] S2. Deposit an Al metal conductive film on the surface of a phosphorus-doped silicon layer using physical vapor deposition.

[0108] S3. The Al metal conductive film obtained in step S2 is processed by photolithography and etching to form the first metal lead 8 and the second metal lead 9.

[0109] S4. Deposit a silicon dioxide thin film using physical vapor deposition, and then grind it to be flush with the height of the first metal lead 8 and the second metal lead 9 by chemical mechanical polishing (CMP).

[0110] S5. Deposit a polycrystalline silicon thin film using physical vapor deposition.

[0111] S6. Use photolithography and etching to etch the polycrystalline silicon thin film into the first nanopillar array 301.

[0112] S7. Fill the space between the nanopillars with a silica film using physical vapor deposition; perform chemical mechanical polishing on the obtained silica film until the surface of the silica film is 1 μm away from the top of the first nanopillar array 301 and make the surface flat. At this time, the silica film covers the first nanopillar array 301.

[0113] S8. Deposit a layer of Al metal conductive film using physical vapor deposition.

[0114] S9. The Al metal conductive film obtained in step S8 is processed by photolithography and etching to form the third metal lead 10 and the fourth metal lead 11.

[0115] S10. Deposit an indium tin oxide (ITO) thin film using physical vapor deposition, and then grind it to be flush with the height of the third metal lead 10 and the fourth metal lead 11 using chemical mechanical polishing.

[0116] S11. The sample obtained in step S10 is subjected to photolithography and etching to remove part of the phosphorus-doped silicon layer, silicon dioxide film and indium tin oxide film, thereby forming the first cantilever beam 5, the central structure 7 and the second cantilever beam 6.

[0117] S12. The sample obtained in step S11 is subjected to photolithography and etching to remove most of the silicon layer and silicon dioxide layer, forming a back cavity and a cylindrical support 1.

[0118] (2) The second substrate is prepared, and the preparation process is as follows: Figure 7 As shown:

[0119] A glass substrate is provided, and a nanopore array is etched on the top surface of the glass substrate using photolithography and etching processes. A polycrystalline silicon thin film is filled in the nanopore array using physical vapor deposition, and then the substrate is polished to be flush with the top surface of the glass substrate using chemical mechanical polishing to obtain a second substrate.

[0120] (3) The first substrate and the second substrate are bonded together so that the top edge of the second substrate is bonded to the open end face of the cylindrical support 1 with a back cavity, thereby obtaining an adjustable superlens.

[0121] Example 2

[0122] This embodiment provides an adjustable superlens, which includes a first substrate, a second substrate, a first voltage controller, and a second voltage controller.

[0123] like Figure 1 As shown, the first substrate includes a cylindrical support 1, which has openings at both ends and extends along a first direction. A main structure is disposed within the cylindrical support 1. The main structure includes, along the first direction, a conductive layer 2, a main insulating layer 3, and a piezoelectric layer 4 stacked sequentially. The conductive layer 2, the main insulating layer 3, and the piezoelectric layer 4 have the same shape and size. The conductive layer 2 is made of phosphorus-doped silicon, and the phosphorus doping amount in the conductive layer 2 is 5 × 10⁻⁶. 7 cm -3 The thickness is 1 μm; the main insulating layer 3 is made of silicon dioxide and has a thickness of 2 μm; the piezoelectric layer 4 is made of aluminum nitride and has a thickness of 0.5 μm; the main structure is divided along a second direction perpendicular to the first direction into a first cantilever beam 5, a central structure 7, and a second cantilever beam 6 connected in sequence. Both the first cantilever beam 5 and the second cantilever beam 6 are Z-shaped structures with openings facing opposite directions, such as... Figure 2 As shown.

[0124] The main insulating layer 3 in the central structure 7 is sequentially divided into a first insulating thin layer, a second insulating thin layer, and a third insulating thin layer along the first direction. The thickness of the first insulating thin layer is 0.5 μm, and the thickness of the third insulating thin layer is 0.5 μm. A first nanopillar array 301 is disposed in the second insulating thin layer. The height direction of the first nanopillar array 301 is parallel to the first direction, and the height of the first nanopillar array 301 is the same as the thickness of the second insulating thin layer. The first nanopillar array 301 is distributed in an array shape, and the material is polycrystalline silicon. The height of the first nanopillar array 301 is 1 μm, the cross-section of each nanopillar is square, and the gap between adjacent nanopillars is 100 nm. The first nanopillar array 301 includes multiple structural units, and the width of the nanopillars in each structural unit is different, ranging from 5 nm to 800 nm.

[0125] The cylindrical support 1 is a straight cylindrical structure; one inner wall of the cylindrical support 1 is connected to the end of the first cantilever beam 5 away from the central structure 7, and the opposite inner wall is connected to the end of the second cantilever beam 6 away from the central structure 7; as Figure 1 As shown, the cylindrical support 1 includes, along the first direction, a bottom layer 101, a bottom insulating layer 102, a supporting conductive layer 103, and a supporting insulating layer 104 stacked sequentially. The bottom layer 101 is made of silicon and has a thickness of 100 μm; the bottom insulating layer 102 is made of silicon dioxide and has a thickness of 0.1 μm; the supporting conductive layer 103 and the main structural conductive layer 2 have the same material and thickness, and the supporting conductive layer 103 and the main structural conductive layer 2 are connected on the same plane; the supporting insulating layer 104 and the main insulating layer 3 have the same material and thickness, and the supporting insulating layer 104 and the main insulating layer 3 are connected on the same plane.

[0126] like Figure 1 , Figure 3 and Figure 4 As shown, a first metal lead 8 and a second metal lead 9 are embedded on the side of the supporting insulating layer 104 near the supporting conductive layer 103. The first metal lead 8 and the second metal lead 9 are made of aluminum metal, and their thicknesses are the same as the thickness of the first insulating thin layer. The first metal lead 8 and the second metal lead 9 are electrically connected to the conductive layer 2 of the first cantilever beam 5 and the conductive layer 2 of the second cantilever beam 6, respectively, and are also electrically connected to the first voltage controller. The voltage range of the first voltage controller is 0-5V.

[0127] like Figure 1 , Figure 2 and Figure 4As shown, a third metal lead 10 and a fourth metal lead 11 are provided on the side of the supporting insulating layer 104 away from the supporting conductive layer 103. The material of the third metal lead 10 and the fourth metal lead 11 is aluminum, and the thickness of the third metal lead 10 and the fourth metal lead 11 is the same as the thickness of the piezoelectric layer 4. The third metal lead 10 and the fourth metal lead 11 are electrically connected to the piezoelectric layer 4 of the first cantilever beam 5 and the piezoelectric layer 4 of the second cantilever beam 6 respectively, and the third metal lead 10 and the fourth metal lead 11 are electrically connected to the second voltage controller; the voltage range of the second voltage controller is 0-5V.

[0128] The first metal lead 8 and the third metal lead 10 are located in the part where the cylindrical support 1 is connected to the first cantilever beam 5; the second metal lead 9 and the fourth metal lead 11 are located in the part where the cylindrical support 1 is connected to the second cantilever beam 6; the conductive layer 2 in the main structure, together with the supporting conductive layer 103, the bottom insulating layer 102 and the bottom layer 101 in the cylindrical support 1, form a back cavity.

[0129] The second substrate contains a second nanopillar array 12, the height direction of which is parallel to the first direction. One end of the second nanopillar array 12 in the height direction is exposed on the top surface of the second substrate, and the other end is located in the second substrate. The exposed end face of the second nanopillar array 12 is flush with the top surface of the second substrate. The second substrate is made of glass with a thickness of 100 μm. The second nanopillar array 12 is arranged in an array and is made of polycrystalline silicon. The height of the second nanopillar array 12 is 1 μm, the cross-section of each nanopillar is square, and the distance between adjacent nanopillars is 100 nm. The second nanopillar array 12 includes multiple structural units, and the width of the nanopillars in each structural unit is different, ranging from 10 nm to 800 nm.

[0130] The top edge of the second substrate is bonded to the side of the bottom layer 101 of the cylindrical support 1 away from the bottom insulating layer 102, such as... Figure 5 As shown.

[0131] This embodiment also provides a method for fabricating the above-mentioned tunable superlens, the method comprising the following steps:

[0132] (1) The first substrate is prepared, and the preparation process is as follows: Figure 6 As shown:

[0133] S1. Provide an SOI silicon wafer, which consists of a silicon layer, a silicon dioxide layer and a phosphorus-doped silicon layer stacked sequentially.

[0134] S2. Deposit an Al metal conductive film on the surface of a phosphorus-doped silicon layer using chemical vapor deposition.

[0135] S3. The Al metal conductive film obtained in step S2 is processed by photolithography and etching to form the first metal lead 8 and the second metal lead 9.

[0136] S4. Deposit a silicon dioxide thin film using chemical vapor deposition, and then grind it to be flush with the height of the first metal lead 8 and the second metal lead 9 by chemical mechanical polishing (CMP).

[0137] S5. Deposit a polycrystalline silicon thin film using chemical vapor deposition.

[0138] S6. Use photolithography and etching to etch the polycrystalline silicon thin film into the first nanopillar array 301.

[0139] S7. A silica film is filled between the nanopillars using chemical vapor deposition. The resulting silica film is then subjected to chemical mechanical polishing until the surface of the silica film is 0.5 μm away from the top of the first nanopillar array 301 and the surface is made flat. At this point, the silica film covers the first nanopillar array 301.

[0140] S8. Deposit an Al metal conductive film using chemical vapor deposition.

[0141] S9. The Al metal conductive film obtained in step S8 is processed by photolithography and etching to form the third metal lead 10 and the fourth metal lead 11.

[0142] S10. Deposit an aluminum nitride film using chemical vapor deposition, and then grind it to be flush with the height of the third metal lead 10 and the fourth metal lead 11 using chemical mechanical polishing.

[0143] S11. The sample obtained in step S10 is subjected to photolithography and etching to remove part of the phosphorus-doped silicon layer, silicon dioxide film and indium tin oxide film, thereby forming the first cantilever beam 5, the central structure 7 and the second cantilever beam 6.

[0144] S12. The sample obtained in step S11 is subjected to photolithography and etching to remove most of the silicon layer and silicon dioxide layer, forming a back cavity and a cylindrical support 1.

[0145] (2) The second substrate is prepared, and the preparation process is as follows: Figure 7 As shown:

[0146] A glass substrate is provided, and a nanopore array is etched on the top surface of the glass substrate using photolithography and etching processes. A polycrystalline silicon thin film is filled in the nanopore array using chemical vapor deposition, and then the substrate is polished to be flush with the top surface of the glass substrate using chemical mechanical polishing to obtain a second substrate.

[0147] (3) The first substrate and the second substrate are bonded together so that the top edge of the second substrate is bonded to the open end face of the cylindrical support 1 with a back cavity, thereby obtaining an adjustable superlens.

[0148] Example 3

[0149] This embodiment provides an adjustable superlens, which includes a first substrate, a second substrate, a first voltage controller, and a second voltage controller.

[0150] like Figure 1 As shown, the first substrate includes a cylindrical support 1, which has openings at both ends and extends along a first direction. A main structure is disposed within the cylindrical support 1. The main structure includes, along the first direction, a conductive layer 2, a main insulating layer 3, and a piezoelectric layer 4 stacked sequentially. The conductive layer 2, the main insulating layer 3, and the piezoelectric layer 4 have the same shape and size. The conductive layer 2 is made of phosphorus-doped silicon, and the phosphorus doping amount in the conductive layer 2 is 5 × 10⁻⁶. 9 cm -3 The thickness is 4μm; the main insulating layer 3 is made of silicon dioxide and has a thickness of 11μm; the piezoelectric layer 4 is made of indium tin oxide (ITO) and has a thickness of 3μm; the main structure is divided along a second direction perpendicular to the first direction into a first cantilever beam 5, a central structure 7, and a second cantilever beam 6 connected in sequence. Both the first cantilever beam 5 and the second cantilever beam 6 are Z-shaped structures with openings facing opposite directions, such as... Figure 2 As shown.

[0151] The main insulating layer 3 in the central structure 7 is sequentially divided into a first insulating thin layer, a second insulating thin layer, and a third insulating thin layer along the first direction. The thickness of the first insulating thin layer is 3 μm, and the thickness of the third insulating thin layer is 3 μm. A first nanopillar array 301 is disposed in the second insulating thin layer. The height direction of the first nanopillar array 301 is parallel to the first direction, and the height of the first nanopillar array 301 is the same as the thickness of the second insulating thin layer. The first nanopillar array 301 is distributed in an array shape. The material is polycrystalline silicon. The height of the first nanopillar array 301 is 5 μm, and the cross-section of each nanopillar is square. The gap between adjacent nanopillars is 500 nm. The first nanopillar array 301 includes multiple structural units. The width of the nanopillars in each structural unit is different, ranging from 5 nm to 800 nm.

[0152] The cylindrical support 1 is a straight cylindrical structure; one inner wall of the cylindrical support 1 is connected to the end of the first cantilever beam 5 away from the central structure 7, and the opposite inner wall is connected to the end of the second cantilever beam 6 away from the central structure 7; as Figure 1As shown, the cylindrical support 1 includes, along the first direction, a bottom layer 101, a bottom insulating layer 102, a supporting conductive layer 103, and a supporting insulating layer 104 stacked sequentially. The bottom layer 101 is made of silicon and has a thickness of 775 μm; the bottom insulating layer 102 is made of silicon dioxide and has a thickness of 2 μm; the supporting conductive layer 103 and the main structure conductive layer 2 are made of the same material and have the same thickness, and the supporting conductive layer 103 and the main structure conductive layer 2 are connected on the same plane; the supporting insulating layer 104 and the main insulating layer 3 are made of the same material and have the same thickness, and the supporting insulating layer 104 and the main insulating layer 3 are connected on the same plane.

[0153] like Figure 1 , Figure 3 and Figure 4 As shown, a first metal lead 8 and a second metal lead 9 are embedded on the side of the supporting insulating layer 104 near the supporting conductive layer 103. The first metal lead 8 and the second metal lead 9 are made of aluminum metal, and their thicknesses are the same as the thickness of the first insulating thin layer. The first metal lead 8 and the second metal lead 9 are electrically connected to the conductive layer 2 of the first cantilever beam 5 and the conductive layer 2 of the second cantilever beam 6, respectively, and are also electrically connected to the first voltage controller. The voltage range of the first voltage controller is 0-5V.

[0154] like Figure 1 , Figure 2 and Figure 4 As shown, a third metal lead 10 and a fourth metal lead 11 are provided on the side of the supporting insulating layer 104 away from the supporting conductive layer 103. The material of the third metal lead 10 and the fourth metal lead 11 is aluminum, and the thickness of the third metal lead 10 and the fourth metal lead 11 is the same as the thickness of the piezoelectric layer 4. The third metal lead 10 and the fourth metal lead 11 are electrically connected to the piezoelectric layer 4 of the first cantilever beam 5 and the piezoelectric layer 4 of the second cantilever beam 6 respectively, and the third metal lead 10 and the fourth metal lead 11 are electrically connected to the second voltage controller; the voltage range of the second voltage controller is 0-5V.

[0155] The first metal lead 8 and the third metal lead 10 are located in the part where the cylindrical support 1 is connected to the first cantilever beam 5; the second metal lead 9 and the fourth metal lead 11 are located in the part where the cylindrical support 1 is connected to the second cantilever beam 6; the conductive layer 2 in the main structure, together with the supporting conductive layer 103, the bottom insulating layer 102 and the bottom layer 101 in the cylindrical support 1, form a back cavity.

[0156] The second substrate contains a second nanopillar array 12, the height direction of which is parallel to the first direction. One end of the second nanopillar array 12 in the height direction is exposed on the top surface of the second substrate, and the other end is located in the second substrate. The exposed end face of the second nanopillar array 12 is flush with the top surface of the second substrate. The second substrate is made of glass with a thickness of 900 μm. The second nanopillar array 12 is arranged in an array and is made of polycrystalline silicon. The height of the second nanopillar array 12 is 5 μm, the cross-section of each nanopillar is square, and the distance between adjacent nanopillars is 500 nm. The second nanopillar array 12 includes multiple structural units, and the width of the nanopillars in each structural unit is different, ranging from 10 nm to 800 nm.

[0157] The top edge of the second substrate is bonded to the side of the bottom layer 101 of the cylindrical support 1 away from the bottom insulating layer 102, such as... Figure 5 As shown.

[0158] This embodiment also provides a method for fabricating the above-mentioned tunable superlens, the method comprising the following steps:

[0159] (1) The first substrate is prepared, and the preparation process is as follows: Figure 6 As shown:

[0160] S1. Provide an SOI silicon wafer, which consists of a silicon layer, a silicon dioxide layer and a phosphorus-doped silicon layer stacked sequentially.

[0161] S2. Deposit an Al metal conductive film on the surface of a phosphorus-doped silicon layer using physical vapor deposition.

[0162] S3. The Al metal conductive film obtained in step S2 is processed by photolithography and etching to form the first metal lead 8 and the second metal lead 9.

[0163] S4. Deposit a silicon dioxide thin film using physical vapor deposition, and then grind it to be flush with the height of the first metal lead 8 and the second metal lead 9 by chemical mechanical polishing (CMP).

[0164] S5. Deposit a polycrystalline silicon thin film using physical vapor deposition.

[0165] S6. Use photolithography and etching to etch the polycrystalline silicon thin film into the first nanopillar array 301.

[0166] S7. Fill the space between the nanopillars with a silica film using physical vapor deposition; perform chemical mechanical polishing on the obtained silica film until the surface of the silica film is 3 μm away from the top of the first nanopillar array 301 and make the surface flat. At this time, the silica film covers the first nanopillar array 301.

[0167] S8. Deposit a layer of Al metal conductive film using physical vapor deposition.

[0168] S9. The Al metal conductive film obtained in step S8 is processed by photolithography and etching to form the third metal lead 10 and the fourth metal lead 11.

[0169] S10. Deposit an indium tin oxide (ITO) thin film using physical vapor deposition, and then grind it to be flush with the height of the third metal lead 10 and the fourth metal lead 11 using chemical mechanical polishing.

[0170] S11. The sample obtained in step S10 is subjected to photolithography and etching to remove part of the phosphorus-doped silicon layer, silicon dioxide film and indium tin oxide film, thereby forming the first cantilever beam 5, the central structure 7 and the second cantilever beam 6.

[0171] S12. The sample obtained in step S11 is subjected to photolithography and etching to remove most of the silicon layer and silicon dioxide layer, forming a back cavity and a cylindrical support 1.

[0172] (2) The second substrate is prepared, and the preparation process is as follows: Figure 7 As shown:

[0173] A glass substrate is provided, and a nanopore array is etched on the top surface of the glass substrate using photolithography and etching processes. A polycrystalline silicon thin film is filled in the nanopore array using physical vapor deposition, and then the substrate is polished to be flush with the top surface of the glass substrate using chemical mechanical polishing to obtain a second substrate.

[0174] (3) The first substrate and the second substrate are bonded together so that the top edge of the second substrate is bonded to the open end face of the cylindrical support 1 with a back cavity, thereby obtaining an adjustable superlens.

[0175] In summary, by Figure 5 As can be seen, when focusing is performed using the superlens provided in Examples 1-3, light can enter from above the second substrate and be focused below the first substrate through the combined action of the second and first nanopillar arrays. Furthermore, since the first nanopillar array in the tunable superlens provided in Examples 1-3 can move up and down along a first direction and simultaneously move left and right along a second direction, meaning the nanopillar geometry formed by the first and second nanopillar arrays is adjustable, the superlens provided by this invention can meet the focusing requirements at different wavelengths, thereby achieving precise control of light sources of different wavelengths. In addition, compared to traditional lenses, the thickness of the superlens provided by this invention is significantly reduced, which is beneficial for the integration of optical devices.

[0176] Comparative Example 1

[0177] This comparative example provides a superlens comprising a glass substrate and a silicon dioxide layer stacked sequentially. The silicon dioxide layer comprises a first silicon dioxide layer, a second silicon dioxide layer, and a third silicon dioxide layer stacked along the direction close to the glass substrate. A nanopillar array is disposed in the second silicon dioxide layer. The nanopillar array is made of polycrystalline silicon, each nanopillar has a square cross-section, each nanopillar has a diameter of 400 nm, and the gap between adjacent nanopillars is 250 nm. The thickness of the first silicon dioxide layer is 1 μm, the thickness of the second silicon dioxide layer is the same as the height of the nanopillar array, which is 3 μm, and the thickness of the third silicon dioxide layer is 1 μm.

[0178] This comparative example also provides a method for preparing the above-mentioned superlens, the method comprising the following steps:

[0179] S1. A first silicon dioxide layer and a polysilicon layer are sequentially deposited on one side surface of a silicon substrate using physical vapor deposition.

[0180] S2. Using photolithography and etching, a polycrystalline silicon layer is grown on the surface of the first silicon dioxide layer in the form of a nanopillar array.

[0181] S3. A polycrystalline silicon layer containing a nanopillar array is filled with silicon dioxide material to form a second silicon dioxide layer containing a nanopillar array. Then, a third silicon dioxide layer is deposited on the second silicon dioxide layer by physical vapor deposition.

[0182] S4. Bond the glass substrate and the structure processed in step S3 to bond the glass substrate to the third silicon dioxide layer. After removing the silicon substrate, the superlens is obtained.

[0183] The nanopillar structure of the superlens provided in Comparative Example 1 is fixed and cannot be adjusted, thus failing to achieve precise control over light sources of different wavelengths. In contrast, the nanopillar structure of the superlens provided in Examples 1-3 of this invention is adjustable, thereby meeting the focusing requirements at different wavelengths and achieving precise control over light sources of different wavelengths.

[0184] The above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. An adjustable superlens, characterized in that, The adjustable superlens includes a first substrate and a second substrate; The first substrate includes a cylindrical support with openings at both ends and extending along a first direction. A main structure is disposed within the cylindrical support. The main structure includes a conductive layer, a main insulating layer, and a piezoelectric layer stacked sequentially along the first direction. The main structure is divided into a first cantilever beam, a central structure, and a second cantilever beam connected sequentially along a second direction perpendicular to the first direction. A first nanopillar array is disposed in the main insulating layer of the central structure. One inner wall of the cylindrical support is connected to the end of the first cantilever beam away from the central structure, and the opposite inner wall is connected to the end of the second cantilever beam away from the central structure; the conductive layer in the main structure and part of the cylindrical support form a back cavity. A second nanopillar array is disposed in the second substrate, with one end of the second nanopillar array exposed on the top surface of the second substrate and the other end located in the second substrate; the exposed end face of the second nanopillar array is flush with the top surface of the second substrate; The top edge of the second substrate is bonded to the open end face of the cylindrical support having a back cavity.

2. The adjustable superlens according to claim 1, characterized in that, In the main structure, the conductive layer, the main insulating layer, and the piezoelectric layer are all the same in shape and size.

3. The adjustable superlens according to claim 1, characterized in that, In the main structure, the conductive layer is made of silicon material doped with phosphorus and / or boron.

4. The adjustable superlens according to claim 1, characterized in that, In the main structure, the thickness of the conductive layer is 0.5μm-4μm.

5. The adjustable superlens according to claim 1, characterized in that, In the main structure, the material of the main insulating layer includes silicon dioxide.

6. The adjustable superlens according to claim 1, characterized in that, In the main structure, the thickness of the main insulating layer is 120nm-11μm.

7. The adjustable superlens according to claim 1, characterized in that, In the main structure, the piezoelectric layer is made of indium tin oxide and / or aluminum nitride.

8. The adjustable superlens according to claim 1, characterized in that, In the main structure, the thickness of the piezoelectric layer is 100nm-3μm.

9. The adjustable superlens according to claim 1, characterized in that, Both the first cantilever beam and the second cantilever beam have a U-shaped structure and their openings face opposite directions.

10. The adjustable superlens according to claim 1, characterized in that, The main insulating layer in the central structure is divided into a first insulating thin layer, a second insulating thin layer and a third insulating thin layer along the first direction; the second insulating thin layer is provided with the first nanopillar array, the height direction of the first nanopillar array is parallel to the first direction, and the height of the first nanopillar array is the same as the thickness of the second insulating thin layer.

11. The adjustable superlens according to claim 10, characterized in that, The thickness of the first insulating layer is 100nm-3μm.

12. The adjustable superlens according to claim 10, characterized in that, The thickness of the third insulating layer is 10 nm to 3 μm.

13. The adjustable superlens according to claim 1, characterized in that, The material of the first nanopillar array includes at least one of polycrystalline silicon, silicon nitride, amorphous silicon, and titanium dioxide.

14. The adjustable superlens according to claim 1, characterized in that, The height of the first nanopillar array is 10 nm-5 μm.

15. The adjustable superlens according to claim 1, characterized in that, In the first nanopillar array, the width of a single nanopillar is 5nm-800nm.

16. The adjustable superlens according to claim 1, characterized in that, In the first nanopillar array, the gap between adjacent nanopillars is 10nm-500nm.

17. The adjustable superlens according to claim 1, characterized in that, The cylindrical support is a straight cylindrical structure.

18. The adjustable superlens according to claim 1, characterized in that, The cylindrical support includes, along the first direction, a sequentially stacked insulating base layer, a supporting conductive layer, and a supporting insulating layer. A first metal lead and a second metal lead are embedded on the side of the supporting insulating layer closest to the supporting conductive layer, respectively electrically connected to the conductive layers of the first and second cantilever beams. A third metal lead and a fourth metal lead are disposed on the side of the supporting insulating layer furthest from the supporting conductive layer, respectively electrically connected to the piezoelectric layers of the first and second cantilever beams. The conductive layer in the main structure, together with the supporting conductive layer and the insulating base layer in the cylindrical support, forms a back cavity.

19. The adjustable superlens according to claim 18, characterized in that, In the cylindrical support, the insulating substrate layer includes a base layer and a base insulating layer stacked sequentially along the first direction, and the side of the base layer away from the base insulating layer is bonded to the top edge of the second substrate.

20. The adjustable superlens according to claim 19, characterized in that, The material used for the underlayment includes silicon.

21. The adjustable superlens according to claim 19, characterized in that, The thickness of the base layer is 10μm-775μm.

22. The adjustable superlens according to claim 19, characterized in that, The material of the base insulating layer includes silicon dioxide.

23. The adjustable superlens according to claim 19, characterized in that, The thickness of the base insulating layer is 0.1μm-2μm.

24. The adjustable superlens according to claim 18, characterized in that, The material supporting the conductive layer includes silicon material doped with phosphorus and / or boron.

25. The adjustable superlens according to claim 18, characterized in that, The thickness of the supporting conductive layer is 0.5μm-4μm.

26. The adjustable superlens according to claim 18, characterized in that, The conductive support layer in the cylindrical support body is connected to the conductive layer in the main structure on the same plane, and the two have the same thickness.

27. The adjustable superlens according to claim 18, characterized in that, The material supporting the insulating layer includes silicon dioxide.

28. The adjustable superlens according to claim 18, characterized in that, The thickness of the supporting insulating layer is 120nm-11μm.

29. The adjustable superlens according to claim 18, characterized in that, The supporting insulation layer in the cylindrical support body and the main insulation layer in the main structure are connected on the same plane and have the same thickness.

30. The adjustable superlens according to claim 18, characterized in that, The portion of the cylindrical support body connected to the first cantilever beam is provided with the first metal lead and the third metal lead; the portion of the cylindrical support body connected to the second cantilever beam is provided with the second metal lead and the fourth metal lead.

31. The adjustable superlens according to claim 30, characterized in that, The thicknesses of the first metal lead and the second metal lead are independently 100 nm to 3 μm.

32. The adjustable superlens according to claim 30, characterized in that, The thicknesses of the third metal lead and the fourth metal lead are independently 100 nm to 3 μm.

33. The adjustable superlens according to claim 18, characterized in that, The adjustable superlens also includes an electric field control component, which is electrically connected to the first metal lead, the second metal lead, the third metal lead, and the fourth metal lead.

34. The adjustable superlens according to claim 33, characterized in that, The electric field control component includes a first voltage controller and a second voltage controller. The first voltage controller is electrically connected to a first metal lead and a second metal lead, and the second voltage controller is electrically connected to a third metal lead and a fourth metal lead.

35. The adjustable superlens according to claim 1, characterized in that, The material of the second substrate includes any one of silicon, glass, or quartz.

36. The adjustable superlens according to claim 1, characterized in that, The thickness of the second substrate is 100μm-900μm.

37. The adjustable superlens according to claim 1, characterized in that, The material of the second nanopillar array includes at least one of polycrystalline silicon, silicon nitride, amorphous silicon, and titanium dioxide.

38. The adjustable superlens according to claim 1, characterized in that, The height direction of the second nanopillar array is parallel to the first direction, and one end of the second nanopillar array in the height direction is exposed to the top surface of the second substrate.

39. The adjustable superlens according to claim 1, characterized in that, The height of the second nanopillar array is 10 nm-5 μm.

40. The adjustable superlens according to claim 1, characterized in that, In the second nanopillar array, the width of a single nanopillar is 10nm-800nm.

41. The adjustable superlens according to claim 1, characterized in that, In the second nanopillar array, the distance between adjacent nanopillars is 100nm-500nm.

42. A method for fabricating an adjustable superlens as described in any one of claims 1-41, characterized in that, The preparation method includes the following steps: (1) Fabrication of the first substrate: A. A substrate is provided, the substrate comprising an insulating front layer and a conductive front layer stacked sequentially; A first metal conductive film is deposited on the surface of the conductive front layer side of the substrate, and a first metal lead and a second metal lead are formed after photolithography and etching. B. A first insulating film is deposited on the conductive front layer surface after step A, such that the height of the first insulating film is the same as that of the first metal lead and the second metal lead. Then, a nanopillar array precursor layer is deposited on the plane composed of the first metal lead, the second metal lead and the first insulating film. After photolithography and etching, the first nanopillar array is formed. C. Fill the spaces between the first nanopillar arrays with a second insulating film, such that the second insulating film covers the first nanopillar arrays; D. A second metal conductive film is deposited on the second insulating film, and a third metal lead and a fourth metal lead are formed after photolithography and etching; E. A piezoelectric film is deposited on the surface of the second insulating film after step D, such that the height of the piezoelectric film is the same as that of the third and fourth metal leads. Then, the obtained structure is subjected to photolithography and etching to form the first substrate. The first substrate includes a cylindrical support with openings at both ends and extending along a first direction. A main structure is disposed within the cylindrical support. The main structure includes a conductive layer, a main insulating layer, and a piezoelectric layer stacked sequentially along the first direction. The main structure is divided into a first cantilever beam, a central structure, and a second cantilever beam connected sequentially along a second direction perpendicular to the first direction. A first nanopillar array is disposed in the main insulating layer of the central structure. One inner wall of the cylindrical support is connected to the end of the first cantilever beam away from the central structure, and the opposite inner wall is connected to the end of the second cantilever beam away from the central structure; the conductive layer in the main structure and part of the cylindrical support form a back cavity. (2) Fabrication of the second substrate: Another substrate is provided, and one side of the substrate is etched into a nanopore array using photolithography and etching processes. Then, nanopillar material is filled into the nanopore array to form a second nanopillar array, resulting in a second substrate. One end of the second nanopillar array is exposed on the top surface of the second substrate, and the other end is located in the second substrate; the exposed end face of the second nanopillar array is flush with the top surface of the second substrate; (3) The first substrate and the second substrate are bonded together such that the top edge of the second substrate is bonded to the open end face of the cylindrical support having a back cavity, thereby obtaining the adjustable superlens.

43. The preparation method according to claim 42, characterized in that, The deposition methods for the first conductive metal film, the first insulating film, the nanopillar array precursor layer, the second insulating film, the second conductive metal film, and the piezoelectric film independently include any one or a combination of at least two of physical vapor deposition, chemical vapor deposition, or atomic layer deposition.

44. The preparation method according to claim 42, characterized in that, The filling method of the nanopillar material includes any one or a combination of at least two of physical vapor deposition, chemical vapor deposition, or atomic layer deposition.

45. An optical device, characterized in that, The optical device includes the adjustable superlens as described in any one of claims 1-41, or the adjustable superlens prepared by the preparation method described in any one of claims 42-44.

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