Adjustable super lens and preparation method and application thereof

Abstract

The invention provides an adjustable super lens and a preparation method and application thereof. The adjustable super lens comprises a first substrate and a second substrate, the first substrate comprises a cylindrical support body, two ends of the cylindrical support body are opened and extend 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 a first direction, and the main body structure is divided into a first cantilever beam, a central structure and a second cantilever beam along a second direction; a first nanorod array is arranged in the main body insulating layer of the central structure; the inner wall of one side of the cylindrical support body is connected with one end of a first cantilever beam, and the inner wall of the opposite side is connected with one end of a second cantilever beam; a back cavity is defined by the conductive layer in the main body structure and part of the cylindrical supporting body; a second nanopillar array is arranged in the second substrate, one end of the second nanopillar array is exposed on the top surface of the second substrate, and the other end of the second nanopillar array is located in the second substrate; and the edge of the top surface of the second substrate is in bonding connection with the open end surface, with the back cavity, of the cylindrical support body.

Description

Technical Field

[0001] The present invention belongs to the field of semiconductor technology and relates to an adjustable super lens and a preparation method and application thereof. Background Art

[0002] Traditional lenses are relatively thick, so researchers have proposed superlenses to reduce their thickness. Superlenses are thin, light, compact, and versatile planar lenses. Superlenses can precisely manipulate the wavefront of light by controlling subwavelength nanostructures to achieve the focusing function of the lens. This superlens composed of nanostructures is tens of thousands of times thinner than traditional lenses, and has revolutionary guiding significance for the integration of optical devices.

[0003] However, the nanostructure of existing superlenses is fixed, which makes the refractive index of the superlens fixed, which makes it impossible for the superlens 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] In view of the shortcomings of the prior art, the purpose of the present invention is to provide an adjustable superlens and its preparation method and application. The nanocolumn geometry in the superlens provided by the present invention is adjustable, so it can meet the focusing requirements at different wavelengths, thereby achieving precise control of light sources of different wavelengths.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] In the first aspect, the present invention provides an adjustable superlens, which includes a first substrate and a second substrate; the first substrate includes a cylindrical support body, the two ends of the cylindrical support body are open and extend along the first direction, and a main structure is arranged in the cylindrical support body; the main structure includes a conductive layer, a main insulating layer and a piezoelectric layer stacked in sequence along the first direction, and the main structure is divided into a first cantilever beam, a central structure and a second cantilever beam connected in sequence along a second direction perpendicular to the first direction; a first nanocolumn array is arranged in the main insulating layer of the central structure; an inner wall on one side of the cylindrical support body is connected to an end of the first cantilever beam away from the central structure, and an inner wall on the other side opposite to the first cantilever beam is connected to an end of the second cantilever beam away from the central structure; the conductive layer in the main structure and part of the cylindrical support body form a back cavity; a second nanocolumn array is arranged in the second substrate, one end of the second nanocolumn array is exposed to the top surface of the second substrate, and the other end is located in the second substrate; the exposed end surface of the second nanocolumn array is flush with the top surface of the second substrate; the edge of the top surface of the second substrate is bonded to the open end surface of the cylindrical support body 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 correspondingly divided into three parts, belonging to the first cantilever beam, the central structure and the second cantilever beam respectively.

[0009] The present invention provides an adjustable superlens, which is provided with a first cantilever beam, a second cantilever beam and a piezoelectric layer and other structures, wherein the first cantilever beam and the second cantilever beam act similarly to a spring, and when an electric field is applied to the conductive layer in the main structure, an electrostatic force is generated between the first cantilever beam and the second cantilever beam, so that the first cantilever beam and the second cantilever beam can be moved in a second direction, thereby driving the first nanocolumn 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 will generate mechanical stress, thereby applying stress to the main insulating layer, and then the first nanocolumn array can be moved in the first direction; in summary, the first nanocolumn array of the present invention can move in the first direction and the second direction, that is, the nanocolumn geometric structure composed of the first nanocolumn array and the second nanocolumn array is adjustable, so the superlens provided by the present invention can meet the focusing requirements at different wavelengths, thereby realizing precise control of light sources of different wavelengths.

[0010] Compared with traditional lenses, the thickness of the metalens provided by the present invention is greatly reduced, which is conducive to 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) and the like.

[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 material of the conductive layer includes silicon material doped with phosphorus and / or boron.

[0014] In the material of the conductive layer of the present invention, the silicon material in the silicon material doped with phosphorus and / or boron includes but is not limited to single crystal 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 is not limited to the listed values, and other unlisted values ​​within the numerical 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, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0018] Preferably, in the main structure, the material of the piezoelectric layer includes 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 is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0020] Preferably, the first cantilever beam and the second cantilever beam are both in a "X"-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 in sequence along the first direction; the first nanocolumn array is arranged in the second insulating thin layer, the height direction of the first nanocolumn array is parallel to the first direction, and the height of the first nanocolumn array is the same as the thickness of the second insulating thin layer.

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

[0023] Preferably, the thickness of the third insulating thin 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 is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

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

[0025] Preferably, the height of the first nanocolumn 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, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0026] Preferably, in the first nanocolumn array, the width of a single nanocolumn 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, and other unlisted values ​​within the numerical range are also applicable.

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

[0028] Preferably, the first nano-column array comprises a plurality of structural units, and the nano-columns in each structural unit have different widths.

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

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

[0031] Preferably, the cylindrical support body includes an insulating base layer, a supporting conductive layer and a supporting insulating layer stacked in sequence along the first direction, and a first metal lead and a second metal lead are embedded in a side of the supporting insulating layer close to the supporting conductive layer, and the first metal lead and the second metal lead are electrically connected to the conductive layer of the first cantilever beam and the conductive layer of the second cantilever beam respectively in a one-to-one correspondence; a third metal lead and a fourth metal lead are arranged on a side of the supporting insulating layer away from the supporting conductive layer, and the third metal lead and the fourth metal lead are electrically connected to the piezoelectric layer of the first cantilever beam and the piezoelectric layer of the second cantilever beam respectively in a one-to-one correspondence; the conductive layer in the main structure and the supporting conductive layer and the insulating base layer in the cylindrical support body form a back cavity.

[0032] Preferably, in the cylindrical support body, the insulating base layer includes a primer layer and a bottom insulating layer stacked in sequence along the first direction, and a surface of the primer layer away from the bottom insulating layer is bonded to an edge of the top surface of the second substrate.

[0033] Preferably, the material of the base layer includes silicon material.

[0034] In the base material of the present invention, silicon material includes but is not limited to single crystal silicon or polycrystalline silicon.

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

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

[0037] Preferably, the thickness of the base insulating layer is 0.1 μm-2 μm, for example, 0.1 μm, 0.2 μm, 0.5 μm, 1 μm, 1.2 μm, 1.5 μm, 1.8 μm or 2 μm, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical 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 0.5 μm-4 μm, for example, it can be 0.5 μm, 0.6 μm, 0.8 μm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm or 4 μm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0040] Preferably, the supporting conductive layer in the cylindrical support body and the conductive layer in the main structure are connected on the same plane, and the two 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, and other unlisted values ​​within the numerical range are also applicable.

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

[0044] Preferably, the first metal lead and the third metal lead are provided in the portion where the tubular support body is connected to the first cantilever beam; and the second metal lead and the fourth metal lead are provided in the portion where the tubular support body is connected to the second cantilever beam.

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

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

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

[0048] Preferably, the adjustable superlens further includes an electric field regulation component, and the electric field regulation component 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 regulating component comprises a first voltage controller and a second voltage controller, the first voltage controller is electrically connected to the first metal lead and the second metal lead, and the second voltage controller is electrically connected to the third metal lead and the fourth metal lead.

[0050] In the present invention, an electric field is applied to the conductive layer in the main structure by the first voltage controller, the first metal lead and the second metal lead, and the voltage of the first voltage controller is adjusted to enable the first nanocolumn array to move in the second direction. An electric field is applied to the piezoelectric layer in the main structure by the second voltage controller, the third metal lead and the fourth metal lead, and the voltage of the second voltage controller is adjusted to enable the first nanocolumn array to move in the 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 material, 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 is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

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

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

[0057] Preferably, the height of the second nanocolumn 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, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0058] Preferably, in the second nanocolumn array, the width of a single nanocolumn 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, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0059] Preferably, the second nano-column array comprises a plurality of structural units, and the nano-columns in each structural unit have different widths.

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

[0061] In a second aspect, the present invention provides a method for preparing the adjustable metalens as described in the first aspect, the preparation method comprising the following steps:

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

[0063] A. providing a substrate, the substrate comprising an insulating base front layer and a conductive front layer stacked in sequence;

[0064] Depositing a first metal conductive film on the surface of one side of the conductive front layer of the substrate, and forming a first metal lead and a second metal lead after photolithography and etching;

[0065] B. depositing a first insulating film on the surface of the conductive front layer treated in step A, so that the first insulating film is flush with the height of the first metal lead and the second metal lead, and then depositing a nanorod array precursor layer on the plane formed by the first metal lead, the second metal lead and the first insulating film, and forming a first nanorod array after photolithography and etching;

[0066] C. filling a second insulating film between the first nanorod arrays, and making the second insulating film cover the first nanorod arrays;

[0067] D. depositing a second metal conductive film on the second insulating film, and forming a third metal lead and a fourth metal lead after photolithography and etching;

[0068] E. depositing a piezoelectric film on the surface of the second insulating film after the treatment in step D, so that the piezoelectric film is flush with the height of the third metal lead and the fourth metal lead, and then performing photolithography and etching on the obtained structure to form a first substrate;

[0069] The first substrate comprises a cylindrical support body, both ends of the cylindrical support body are open and extend along a first direction, 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 stacked in sequence along the first direction, and the main body structure is divided into a first cantilever beam, a central structure and a second cantilever beam connected in sequence along a second direction perpendicular to the first direction; a first nanocolumn array is arranged in the main body insulating layer of the central structure;

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

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

[0072] Providing another substrate, etching one side of the substrate into a nanohole array by photolithography and etching, and then filling the nanohole array with nanocolumn material to form a second nanocolumn array, thereby obtaining a second substrate:

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

[0074] (3) Bonding the first substrate and the second substrate so that the top edge of the second substrate is bonded to the open end surface of the cylindrical support having the back cavity, thereby obtaining the adjustable metalens.

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

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

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

[0078] In a third aspect, the present invention provides an optical device, comprising the adjustable superlens described in the first aspect, or the adjustable superlens prepared by the preparation method described in the second aspect.

[0079] The numerical range described in the present invention not only includes the point values ​​listed above, but also includes any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0080] Compared with the prior art, the present invention has the following beneficial effects:

[0081] (1) The present invention provides an adjustable superlens, which is provided with a first cantilever beam, a second cantilever beam and a piezoelectric layer, wherein the first cantilever beam and the second cantilever beam act similarly to a spring, and when an electric field is applied to the conductive layer in the main structure, an electrostatic force is generated between the first cantilever beam and the second cantilever beam, so that the first cantilever beam and the second cantilever beam can move in the second direction, thereby driving the first nanocolumn 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 will generate mechanical stress, thereby applying stress to the main insulating layer, thereby enabling the first nanocolumn array to move in the first direction; in summary, the first nanocolumn array of the present invention can move in the first direction and the second direction, that is, the nanocolumn geometric structure composed of the first nanocolumn array and the second nanocolumn array is adjustable, so the superlens provided by the present invention can meet the focusing requirements at different wavelengths, thereby realizing precise control of light sources of different wavelengths.

[0082] (2) Compared with traditional lenses, the thickness of the metalens provided by the present invention is greatly reduced, which is conducive to the integration of optical devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0083] Figure 1 It is a schematic front cross-sectional view of the first substrate in Examples 1-3 of the present invention.

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

[0085] Figure 3 It is a schematic top view cross-sectional diagram of the first substrate in Examples 1-3 of the present invention.

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

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

[0088] Figure 6Schematic diagram of the process of preparing the first substrate in Examples 1-3 of the present invention.

[0089] Figure 7 Schematic diagram of the process of preparing the second substrate in Examples 1-3 of the present invention.

[0090] Among them, 1-cylindrical support body; 101-base layer; 102-base insulating layer; 103-support conductive layer; 104-support insulating layer; 2-conductive layer; 3-main insulating layer; 301-first nanocolumn 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 nanocolumn array. DETAILED DESCRIPTION

[0091] It should be understood that, in the description of the present invention, the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0092] It should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "disposed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0093] The technical solution of the present invention is further illustrated below through specific implementation methods.

[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 body 1, both ends of the cylindrical support body 1 are open and extend along a first direction, and a main structure is arranged in the cylindrical support body 1; the main structure includes a conductive layer 2, a main insulating layer 3 and a piezoelectric layer 4 stacked in sequence along the first direction, wherein the conductive layer 2, the main insulating layer 3 and the piezoelectric layer 4 are of the same shape and size, the conductive layer 2 is made of silicon doped with phosphorus, and the phosphorus doping amount in the conductive layer 2 is 5×10 5 cm -3 , with a thickness of 2 μm; the main insulating layer 3 is made of silicon dioxide with a thickness of 5 μm; the piezoelectric layer 4 is made of indium tin oxide (ITO) with a thickness of 1.5 μm; the main structure is divided into a first cantilever beam 5, a central structure 7 and a second cantilever beam 6 connected in sequence along a second direction perpendicular to the first direction, the first cantilever beam 5 and the second cantilever beam 6 are both in a "X" shape, and the openings face in opposite directions, such as Figure 2 shown.

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

[0098] The cylindrical support body 1 is a straight cylindrical structure; the inner wall on one side of the cylindrical support body 1 is connected to the end of the first cantilever beam 5 away from the central structure 7, and the inner wall on the other side is connected to the end of the second cantilever beam 6 away from the central structure 7; Figure 1 As shown, the cylindrical support body 1 includes a base layer 101, a base insulating layer 102, a support conductive layer 103 and a support insulating layer 104 stacked in sequence along the first direction, wherein the base layer 101 is made of silicon with a thickness of 350 μm; the base insulating layer 102 is made of silicon dioxide with a thickness of 1 μm; the support conductive layer 103 and the main structure conductive layer 2 have the same material and thickness, and the support conductive layer 103 and the main structure conductive layer 2 are connected on the same plane; the support insulating layer 104 and the main insulating layer 3 have the same material and thickness, and the support 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, the first metal lead 8 and the second metal lead 9 are embedded on one side of the supporting insulating layer 104 close to the supporting conductive layer 103. The material of the first metal lead 8 and the second metal lead 9 is aluminum metal. The thickness of the first metal lead 8 and the second metal lead 9 is the same as the thickness of the first insulating film. 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 the first metal lead 8 and the second metal lead 9 are 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 arranged on a surface 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 are aluminum metal, and the thickness of the third metal lead 10 and the fourth metal lead 11 are 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 portion where the tubular 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 portion where the tubular support 1 is connected to the second cantilever beam 6; the conductive layer 2 in the main structure and the supporting conductive layer 103, the bottom insulating layer 102 and the bottom layer 101 in the tubular support 1 form a back cavity;

[0102] A second nanocolumn array 12 is arranged in the second substrate, and the height direction of the second nanocolumn array 12 is parallel to the first direction. One end of the second nanocolumn array 12 in the height direction is exposed to the top surface of the second substrate, and the other end is located in the second substrate; the exposed end surface of the second nanocolumn array 12 is flush with the top surface of the second substrate; wherein the material of the second substrate is glass, and the thickness is 450μm; the second nanocolumn array 12 is distributed in an array shape, and the material is polycrystalline silicon, the height of the second nanocolumn array 12 is 3μm, the cross-section of each nanocolumn is square, and the distance between adjacent nanocolumns is 300nm; the second nanocolumn array 12 includes multiple structural units, and the width of the nanocolumns in each structural unit is different, and the width ranges from 10nm to 800nm.

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

[0104] This embodiment also provides a method for preparing the above-mentioned adjustable metalens, and the preparation method comprises the following steps:

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

[0106] S1. Provide an SOI silicon wafer, wherein the SOI silicon wafer is composed of a silicon layer, a silicon dioxide layer, and a silicon layer doped with phosphorus that are stacked in sequence.

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

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

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

[0110] S5. Depositing a polysilicon film by physical vapor deposition.

[0111] S6 , etching the polysilicon film into a first nanorod array 301 by photolithography and etching.

[0112] S7, using physical vapor deposition to fill silicon dioxide film between the nano-pillars; performing chemical mechanical grinding on the obtained silicon dioxide film until the surface of the silicon dioxide film is 1 μm away from the top of the first nano-pillar array 301 and the surface is flattened, at which time the silicon dioxide film covers the first nano-pillar array 301.

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

[0114] S9 , using photolithography and etching to process the Al metal conductive film obtained in step S8 to form a third metal lead 10 and a fourth metal lead 11 .

[0115] S10 , depositing an indium tin oxide (ITO) thin film by physical vapor deposition, and then grinding it by chemical mechanical polishing until it is flush with the third metal lead 10 and the fourth metal lead 11 .

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

[0117] S12, performing photolithography and etching on the sample obtained in step S11 to remove most of the silicon layer and the silicon dioxide layer to form a back cavity and a cylindrical support body 1.

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

[0119] A glass substrate is provided, and a nanohole array is etched on the top surface of the glass substrate using photolithography and etching processes; a polysilicon film is filled in the nanohole array using physical vapor deposition, and then chemical mechanical grinding is used to grind it to be flush with the top surface of the glass substrate to obtain a second substrate.

[0120] (3) Bonding the first substrate and the second substrate so that the top edge of the second substrate is bonded to the open end surface of the cylindrical support body 1 having the 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 body 1, both ends of the cylindrical support body 1 are open and extend along a first direction, and a main structure is arranged in the cylindrical support body 1; the main structure includes a conductive layer 2, a main insulating layer 3 and a piezoelectric layer 4 stacked in sequence along the first direction, wherein the conductive layer 2, the main insulating layer 3 and the piezoelectric layer 4 are of the same shape and size, the conductive layer 2 is made of silicon doped with phosphorus, and the phosphorus doping amount in the conductive layer 2 is 5×10 7 cm -3 , with a thickness of 1 μm; the main insulating layer 3 is made of silicon dioxide with a thickness of 2 μm; the piezoelectric layer 4 is made of aluminum nitride with a thickness of 0.5 μm; the main structure is divided into a first cantilever beam 5, a central structure 7 and a second cantilever beam 6 connected in sequence along a second direction perpendicular to the first direction, the first cantilever beam 5 and the second cantilever beam 6 are both in a "X" shape, and the openings face in opposite directions, such as Figure 2 shown.

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

[0125] The cylindrical support body 1 is a straight cylindrical structure; the inner wall on one side of the cylindrical support body 1 is connected to the end of the first cantilever beam 5 away from the central structure 7, and the inner wall on the other side is connected to the end of the second cantilever beam 6 away from the central structure 7; Figure 1 As shown, the cylindrical support body 1 includes a base layer 101, a base insulating layer 102, a support conductive layer 103 and a support insulating layer 104 stacked in sequence along the first direction, wherein the base layer 101 is made of silicon with a thickness of 100 μm; the base insulating layer 102 is made of silicon dioxide with a thickness of 0.1 μm; the support conductive layer 103 and the main structure conductive layer 2 have the same material and thickness, and the support conductive layer 103 and the main structure conductive layer 2 are connected on the same plane; the support insulating layer 104 and the main insulating layer 3 have the same material and thickness, and the support 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, the first metal lead 8 and the second metal lead 9 are embedded on one side of the supporting insulating layer 104 close to the supporting conductive layer 103. The material of the first metal lead 8 and the second metal lead 9 is aluminum metal. The thickness of the first metal lead 8 and the second metal lead 9 is the same as the thickness of the first insulating film. 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 the first metal lead 8 and the second metal lead 9 are 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 arranged on a surface 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 are aluminum metal, and the thickness of the third metal lead 10 and the fourth metal lead 11 are 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 portion where the tubular support body 1 is connected to the first cantilever beam 5; the second metal lead 9 and the fourth metal lead 11 are located in the portion where the tubular support body 1 is connected to the second cantilever beam 6; the conductive layer 2 in the main structure and the supporting conductive layer 103, the bottom insulating layer 102 and the bottom layer 101 in the tubular support body 1 form a back cavity.

[0129] A second nanocolumn array 12 is arranged in the second substrate, and the height direction of the second nanocolumn array 12 is parallel to the first direction. One end of the second nanocolumn array 12 in the height direction is exposed to the top surface of the second substrate, and the other end is located in the second substrate; the exposed end surface of the second nanocolumn array 12 is flush with the top surface of the second substrate; wherein the material of the second substrate is glass, and the thickness is 100μm; the second nanocolumn array 12 is distributed in an array shape, and the material is polycrystalline silicon, the height of the second nanocolumn array 12 is 1μm, the cross-section of each nanocolumn is square, and the distance between adjacent nanocolumns is 100nm; the second nanocolumn array 12 includes multiple structural units, and the width of the nanocolumns in each structural unit is different, and the width ranges from 10nm to 800nm.

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

[0131] This embodiment also provides a method for preparing the above-mentioned adjustable metalens, and the preparation method comprises the following steps:

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

[0133] S1. Provide an SOI silicon wafer, wherein the SOI silicon wafer is composed of a silicon layer, a silicon dioxide layer, and a silicon layer doped with phosphorus that are stacked in sequence.

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

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

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

[0137] S5. Deposit a polysilicon film by chemical vapor deposition.

[0138] S6 , etching the polysilicon film into a first nanorod array 301 by photolithography and etching.

[0139] S7, using chemical vapor deposition to fill silicon dioxide film between the nano-pillars; performing chemical mechanical polishing on the obtained silicon dioxide film until the surface of the silicon dioxide film is 0.5 μm away from the top of the first nano-pillar array 301 and the surface is flattened, at which time the silicon dioxide film covers the first nano-pillar array 301.

[0140] S8. Deposit a layer of Al metal conductive film using chemical vapor deposition.

[0141] S9 , using photolithography and etching to process the Al metal conductive film obtained in step S8 to form a third metal lead 10 and a fourth metal lead 11 .

[0142] S10 , depositing an aluminum nitride film by chemical vapor deposition, and then grinding it by chemical mechanical polishing until it is flush with the third metal lead 10 and the fourth metal lead 11 .

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

[0144] S12, performing photolithography and etching on the sample obtained in step S11 to remove most of the silicon layer and the silicon dioxide layer to form a back cavity and a cylindrical support body 1.

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

[0146] A glass substrate is provided, and a nanohole array is etched on the top surface of the glass substrate using photolithography and etching processes; a polysilicon film is filled in the nanohole array using chemical vapor deposition, and then chemical mechanical grinding is used to grind it to be flush with the top surface of the glass substrate to obtain a second substrate.

[0147] (3) Bonding the first substrate and the second substrate so that the top edge of the second substrate is bonded to the open end surface of the cylindrical support body 1 having the 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 body 1, both ends of the cylindrical support body 1 are open and extend along a first direction, and a main structure is arranged in the cylindrical support body 1; the main structure includes a conductive layer 2, a main insulating layer 3 and a piezoelectric layer 4 stacked in sequence along the first direction, wherein the conductive layer 2, the main insulating layer 3 and the piezoelectric layer 4 are of the same shape and size, the conductive layer 2 is made of silicon doped with phosphorus, and the phosphorus doping amount in the conductive layer 2 is 5×10 9 cm -3 , with a thickness of 4 μm; the main insulating layer 3 is made of silicon dioxide with a thickness of 11 μm; the piezoelectric layer 4 is made of indium tin oxide (ITO) with a thickness of 3 μm; the main structure is divided into a first cantilever beam 5, a central structure 7 and a second cantilever beam 6 connected in sequence along a second direction perpendicular to the first direction, the first cantilever beam 5 and the second cantilever beam 6 are both in a "X" shape, and the openings face opposite directions, such as Figure 2 shown.

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

[0152] The cylindrical support body 1 is a straight cylindrical structure; the inner wall on one side of the cylindrical support body 1 is connected to the end of the first cantilever beam 5 away from the central structure 7, and the inner wall on the other side is connected to the end of the second cantilever beam 6 away from the central structure 7; Figure 1As shown, the cylindrical support body 1 includes a base layer 101, a base insulating layer 102, a support conductive layer 103 and a support insulating layer 104 stacked in sequence along the first direction, wherein the base layer 101 is made of silicon with a thickness of 775 μm; the base insulating layer 102 is made of silicon dioxide with a thickness of 2 μm; the support conductive layer 103 and the main structure conductive layer 2 have the same material and thickness, and the support conductive layer 103 and the main structure conductive layer 2 are connected on the same plane; the support insulating layer 104 and the main insulating layer 3 have the same material and thickness, and the support 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, the first metal lead 8 and the second metal lead 9 are embedded on one side of the supporting insulating layer 104 close to the supporting conductive layer 103. The material of the first metal lead 8 and the second metal lead 9 is aluminum metal. The thickness of the first metal lead 8 and the second metal lead 9 is the same as the thickness of the first insulating film. 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 the first metal lead 8 and the second metal lead 9 are 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 arranged on a surface 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 are aluminum metal, and the thickness of the third metal lead 10 and the fourth metal lead 11 are 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 portion where the tubular support body 1 is connected to the first cantilever beam 5; the second metal lead 9 and the fourth metal lead 11 are located in the portion where the tubular support body 1 is connected to the second cantilever beam 6; the conductive layer 2 in the main structure and the supporting conductive layer 103, the bottom insulating layer 102 and the bottom layer 101 in the tubular support body 1 form a back cavity.

[0156] A second nanocolumn array 12 is arranged in the second substrate, and the height direction of the second nanocolumn array 12 is parallel to the first direction. One end of the second nanocolumn array 12 in the height direction is exposed to the top surface of the second substrate, and the other end is located in the second substrate; the exposed end surface of the second nanocolumn array 12 is flush with the top surface of the second substrate; wherein the material of the second substrate is glass, and the thickness is 900μm; the second nanocolumn array 12 is distributed in an array shape, and the material is polycrystalline silicon, the height of the second nanocolumn array 12 is 5μm, the cross-section of each nanocolumn is square, and the distance between adjacent nanocolumns is 500nm; the second nanocolumn array 12 includes multiple structural units, and the width of the nanocolumns in each structural unit is different, and the width ranges from 10nm to 800nm.

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

[0158] This embodiment also provides a method for preparing the above-mentioned adjustable metalens, and the preparation method comprises the following steps:

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

[0160] S1. Provide an SOI silicon wafer, wherein the SOI silicon wafer is composed of a silicon layer, a silicon dioxide layer, and a silicon layer doped with phosphorus that are stacked in sequence.

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

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

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

[0164] S5. Depositing a polysilicon film by physical vapor deposition.

[0165] S6 , etching the polysilicon film into a first nanorod array 301 by photolithography and etching.

[0166] S7. Fill the space between the nano-pillars with a silicon dioxide film by physical vapor deposition; perform chemical mechanical polishing on the obtained silicon dioxide film until the surface of the silicon dioxide film is 3 μm away from the top of the first nano-pillar array 301 and the surface is flattened. At this time, the silicon dioxide film covers the first nano-pillar array 301.

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

[0168] S9 , using photolithography and etching to process the Al metal conductive film obtained in step S8 to form a third metal lead 10 and a fourth metal lead 11 .

[0169] S10 , depositing an indium tin oxide (ITO) thin film by physical vapor deposition, and then grinding it by chemical mechanical polishing until it is flush with the third metal lead 10 and the fourth metal lead 11 .

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

[0171] S12, performing photolithography and etching on the sample obtained in step S11 to remove most of the silicon layer and the silicon dioxide layer to form a back cavity and a cylindrical support body 1.

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

[0173] A glass substrate is provided, and a nanohole array is etched on the top surface of the glass substrate using photolithography and etching processes; a polysilicon film is filled in the nanohole array using physical vapor deposition, and then chemical mechanical grinding is used to grind it to be flush with the top surface of the glass substrate to obtain a second substrate.

[0174] (3) Bonding the first substrate and the second substrate so that the top edge of the second substrate is bonded to the open end surface of the cylindrical support body 1 having the back cavity, thereby obtaining an adjustable superlens.

[0175] In summary, Figure 5 It can be seen that when the superlens provided by Examples 1-3 is used for focusing, light can be injected from above the second substrate, and through the joint action of the second nanocolumn array and the first nanocolumn array, it is focused below the first substrate. In addition, since in the adjustable superlens provided by Examples 1-3 of the present invention, the first nanocolumn array can move up and down along the first direction, and can move left and right along the second direction, that is, the nanocolumn geometric structure composed of the first nanocolumn array and the second nanocolumn array is adjustable, the superlens provided by the present invention can meet the focusing requirements at different wavelengths, thereby realizing the precise control of light sources of different wavelengths. In addition, compared with traditional lenses, the thickness of the superlens provided by the present invention is greatly reduced, which is conducive to the integration of optical devices.

[0176] Comparative Example 1

[0177] The present comparative example provides a superlens, which includes a glass substrate and a silicon dioxide layer stacked in sequence, wherein the silicon dioxide layer includes a first silicon dioxide layer, a second silicon dioxide layer and a third silicon dioxide layer stacked in a direction close to the glass substrate, a nanocolumn array is arranged in the second silicon dioxide layer, the material of the nanocolumn array is polycrystalline silicon, the cross-section of each nanocolumn is square, the diameter of each nanocolumn is 400nm, and the gap between adjacent nanocolumns is 250nm; the thickness of the first silicon dioxide layer is 1μm, the thickness of the second silicon dioxide layer is the same as the height of the nanocolumn array, both are 3μm, and the thickness of the third silicon dioxide layer is 1μm.

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

[0179] S1. Depositing a first silicon dioxide layer and a polysilicon layer in sequence on one side surface of a silicon substrate by physical vapor deposition.

[0180] S2. Using photolithography and etching methods, a polysilicon layer is grown on the surface of the first silicon dioxide layer in the form of a nano-column array.

[0181] S3, filling the polysilicon layer of the nanocolumn array with a silicon dioxide material to form a second silicon dioxide layer containing the nanocolumn array, and then depositing a third silicon dioxide layer on the second silicon dioxide layer by physical vapor deposition.

[0182] S4, bonding the glass substrate and the structure processed in step S3, so that the glass substrate is bonded to the third silicon dioxide layer, and after removing the silicon substrate, the super lens is obtained.

[0183] The nano-pillar structure of the super-lens provided in Comparative Example 1 is fixed and cannot be adjusted, so it is impossible to achieve precise control of light sources of different wavelengths. However, the nano-pillar structure of the super-lens provided in Examples 1-3 of the present invention is adjustable, so as to meet the focusing requirements at different wavelengths and achieve precise control of light sources of different wavelengths.

[0184] The above description is only a specific implementation mode 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 thought of by those skilled in the art within the technical scope disclosed by the present invention are within the protection scope and disclosure scope of the present invention.

Claims

1. An adjustable metalens, characterized in that: The adjustable metalens includes a first substrate and a second substrate; The first substrate comprises a cylindrical support body, both ends of the cylindrical support body are open and extend along a first direction, 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 stacked in sequence along the first direction, and the main body structure is divided into a first cantilever beam, a central structure and a second cantilever beam connected in sequence along a second direction perpendicular to the first direction; a first nanocolumn array is arranged in the main body insulating layer of the central structure; One inner wall of the cylindrical support body is connected to one end of the first cantilever beam away from the central structure, and the other inner wall of the opposite side is connected to one end of the second cantilever beam away from the central structure; the conductive layer in the main structure and part of the cylindrical support body form a back cavity; A second nanorod array is disposed in the second substrate, one end of the second nanorod array is exposed to the top surface of the second substrate, and the other end is located in the second substrate; the exposed end surface of the second nanorod array is flush with the top surface of the second substrate; The top edge of the second substrate is bonded to the open end surface of the cylindrical support body having the back cavity.

2. The adjustable metalens 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; Preferably, in the main structure, the material of the conductive layer includes silicon material doped with phosphorus and / or boron; Preferably, in the main structure, the thickness of the conductive layer is 0.5 μm-4 μm; Preferably, in the main structure, the material of the main insulating layer includes silicon dioxide; Preferably, in the main structure, the thickness of the main insulating layer is 120nm-11μm; Preferably, in the main structure, the material of the piezoelectric layer includes indium tin oxide and / or aluminum nitride; Preferably, in the main structure, the thickness of the piezoelectric layer is 100nm-3μm; Preferably, the first cantilever beam and the second cantilever beam are both in a "X"-shaped structure, and their openings face opposite directions.

3. The adjustable metalens according to claim 1 or 2, 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 in sequence along the first direction; the first nanocolumn array is provided in the second insulating thin layer, the height direction of the first nanocolumn array is parallel to the first direction, and the height of the first nanocolumn array is the same as the thickness of the second insulating thin layer; Preferably, the thickness of the first insulating thin layer is 100 nm-3 μm; Preferably, the thickness of the third insulating thin layer is 10 nm-3 μm; Preferably, the material of the first nanorod array includes at least one of polycrystalline silicon, silicon nitride, amorphous silicon and titanium dioxide; Preferably, the height of the first nanocolumn array is 10 nm-5 μm; Preferably, in the first nanocolumn array, the width of a single nanocolumn is 5nm-800nm; Preferably, in the first nanocolumn array, the gap between adjacent nanocolumns is 10 nm-500 nm.

4. The adjustable metalens according to any one of claims 1 to 3, characterized in that: The cylindrical support body is a straight cylindrical structure; Preferably, the cylindrical support body comprises an insulating base layer, a supporting conductive layer and a supporting insulating layer stacked in sequence along the first direction, a first metal lead and a second metal lead are embedded on a side of the supporting insulating layer close to the supporting conductive layer, and the first metal lead and the second metal lead are electrically connected to the conductive layer of the first cantilever beam and the conductive layer of the second cantilever beam respectively in a one-to-one correspondence; a third metal lead and a fourth metal lead are arranged on a side of the supporting insulating layer away from the supporting conductive layer, and the third metal lead and the fourth metal lead are electrically connected to the piezoelectric layer of the first cantilever beam and the piezoelectric layer of the second cantilever beam respectively in a one-to-one correspondence; the conductive layer in the main structure and the supporting conductive layer and the insulating base layer in the cylindrical support body form a back cavity; Preferably, in the cylindrical support body, the insulating base layer includes a primer layer and a primer insulating layer stacked in sequence along the first direction, and a side of the primer layer away from the primer insulating layer is bonded to an edge of the top surface of the second substrate; Preferably, the material of the base layer includes silicon material; Preferably, the thickness of the primer layer is 10 μm-775 μm; Preferably, the material of the bottom insulating layer includes silicon dioxide; Preferably, the thickness of the bottom insulating layer is 0.1 μm-2 μm.

5. The adjustable metalens according to claim 4, characterized in that: The material of the supporting conductive layer includes silicon material doped with phosphorus and / or boron; Preferably, the thickness of the supporting conductive layer is 0.5 μm-4 μm; Preferably, the supporting conductive layer in the cylindrical support body and the conductive layer in the main structure are connected on the same plane, and the two have the same thickness; Preferably, the material of the supporting insulating layer comprises silicon dioxide; Preferably, the thickness of the supporting insulating layer is 120 nm-11 μm; Preferably, the support insulating layer in the cylindrical support body and the main body insulating layer in the main body structure are connected on the same plane, and the two have the same thickness.

6. The adjustable metalens according to claim 4 or 5, characterized in that: The first metal lead and the third metal lead are arranged in the portion where the cylindrical support body is connected to the first cantilever beam; the second metal lead and the fourth metal lead are arranged in the portion where the cylindrical support body is connected to the second cantilever beam; Preferably, the thickness of the first metal lead and the second metal lead are independently 100 nm-3 μm; Preferably, the thickness of the third metal lead and the fourth metal lead are independently 100 nm-3 μm; Preferably, the adjustable metalens further comprises an electric field regulating component, and the electric field regulating component is electrically connected to the first metal lead, the second metal lead, the third metal lead and the fourth metal lead; Preferably, the electric field regulating component comprises a first voltage controller and a second voltage controller, the first voltage controller is electrically connected to the first metal lead and the second metal lead, and the second voltage controller is electrically connected to the third metal lead and the fourth metal lead.

7. The adjustable metalens according to any one of claims 1 to 6, characterized in that: The material of the second substrate includes any one of silicon material, glass or quartz; Preferably, the thickness of the second substrate is 100 μm-900 μm; Preferably, the material of the second nanorod array includes at least one of polysilicon, silicon nitride, amorphous silicon and titanium dioxide; Preferably, the height direction of the second nanorod array is parallel to the first direction, and one end of the second nanorod array in the height direction is exposed to the top surface of the second substrate; Preferably, the height of the second nanocolumn array is 10 nm-5 μm; Preferably, in the second nanocolumn array, the width of a single nanocolumn is 10nm-800nm; Preferably, in the second nanocolumn array, the distance between adjacent nanocolumns is 100 nm-500 nm.

8. A method for preparing an adjustable metalens according to any one of claims 1 to 7, characterized in that: The preparation method comprises the following steps: (1) Preparation of the first substrate: A. providing a substrate, the substrate comprising an insulating base front layer and a conductive front layer stacked in sequence; Depositing a first metal conductive film on the surface of one side of the conductive front layer of the substrate, and forming a first metal lead and a second metal lead after photolithography and etching; B. depositing a first insulating film on the surface of the conductive front layer treated in step A, so that the first insulating film is flush with the height of the first metal lead and the second metal lead, and then depositing a nanorod array precursor layer on the plane formed by the first metal lead, the second metal lead and the first insulating film, and forming a first nanorod array after photolithography and etching; C. filling a second insulating film between the first nanorod arrays, and making the second insulating film cover the first nanorod arrays; D. depositing a second metal conductive film on the second insulating film, and forming a third metal lead and a fourth metal lead after photolithography and etching; E. depositing a piezoelectric film on the surface of the second insulating film after the treatment in step D, so that the piezoelectric film is flush with the height of the third metal lead and the fourth metal lead, and then performing photolithography and etching on the obtained structure to form a first substrate; The first substrate comprises a cylindrical support body, both ends of the cylindrical support body are open and extend along a first direction, 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 stacked in sequence along the first direction, and the main body structure is divided into a first cantilever beam, a central structure and a second cantilever beam connected in sequence along a second direction perpendicular to the first direction; a first nanocolumn array is arranged in the main body insulating layer of the central structure; One inner wall of the cylindrical support body is connected to one end of the first cantilever beam away from the central structure, and the other inner wall of the opposite side is connected to one end of the second cantilever beam away from the central structure; the conductive layer in the main structure and part of the cylindrical support body form a back cavity; (2) Preparation of the second substrate: Providing another substrate, etching one side of the substrate into a nanohole array by photolithography and etching, and then filling the nanohole array with nanocolumn material to form a second nanocolumn array, thereby obtaining a second substrate: One end of the second nanorod array is exposed to the top surface of the second substrate, and the other end is located in the second substrate; the exposed end surface of the second nanorod array is flush with the top surface of the second substrate; (3) Bonding the first substrate and the second substrate so that the top edge of the second substrate is bonded to the open end surface of the cylindrical support having the back cavity, thereby obtaining the adjustable metalens.

9. The preparation method according to claim 8, characterized in that: The deposition methods of the first metal conductive film, the first insulating film, the nanorod array precursor layer, the second insulating film, the second metal conductive film and the piezoelectric film independently include any one of physical vapor deposition, chemical vapor deposition or atomic layer deposition or a combination of at least two thereof; Preferably, the filling method of the nano-column material includes any one of physical vapor deposition, chemical vapor deposition or atomic layer deposition, or a combination of at least two of them.

10. An optical device, characterized in that: The optical device includes the adjustable superlens described in any one of claims 1 to 7, or the adjustable superlens prepared by the preparation method described in claim 8 or 9.

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