Nonlinear optical crystal cavity and preparation method thereof

Abstract

The invention relates to a nonlinear optical crystal cavity and a preparation method thereof. The nonlinear optical crystal cavity comprises at least two layers of Van der Waals material layers which are arranged in a stacked mode and spaced, and the materials of the Van der Waals material layers comprise Van der Waals materials with center inversion asymmetry; the optical resonant cavity comprises two layers of distributed Bragg reflectors which are oppositely arranged, and the two layers of distributed Bragg reflectors are arranged on the two surfaces of the outermost side in the stacking direction of the Van der Waals material layer respectively; the driving assembly is connected to the Van der Waals material layers, and the driving assembly is used for adjusting the rotating angle between the adjacent Van der Waals material layers and the interval between the adjacent Van der Waals material layers. The nonlinear optical crystal cavity provided by the invention has the capabilities of adjustable function and wide-band working, and can realize high nonlinear conversion efficiency under different wavelengths at the same time.

Description

Technical Field

[0001] The present application relates to the field of optical crystal technology, and in particular to a nonlinear optical crystal cavity and a preparation method thereof. Background Art

[0002] Nonlinear optical crystals play an important role in applications such as laser communications, laser processing, and lidar. With the continuous development of optical technology, the demand for miniaturized and functionally tunable nonlinear optical crystal cavities is becoming increasingly urgent.

[0003] Optical resonators can improve the conversion efficiency of nonlinear optical crystals. However, while optical resonators based on traditional nonlinear optical crystals can achieve high conversion efficiency within a pre-designed wavelength range, they can only operate near the pre-designed wavelength range and lack the ability to be functionally adjustable or operate over a wide wavelength band. Summary of the Invention

[0004] Based on this, it is necessary to provide a nonlinear optical crystal cavity and a method for preparing the same. The nonlinear optical crystal cavity of the present application has adjustable functions and the ability to operate in a wide band, while being able to achieve high nonlinear conversion efficiency at different wavelengths.

[0005] In a first aspect, the present application provides a nonlinear optical crystal cavity, comprising:

[0006] At least two stacked and spaced-apart van der Waals material layers, wherein the van der Waals material layers include a van der Waals material having central inversion asymmetry;

[0007] An optical resonant cavity, comprising two layers of distributed Bragg reflectors arranged opposite to each other, the two layers of distributed Bragg reflectors being respectively arranged on the two outermost surfaces in the stacking direction of the van der Waals material layer;

[0008] A driving component is connected to the van der Waals material layer, and the driving component is used to adjust the rotation angle between adjacent van der Waals material layers and the interval between adjacent van der Waals material layers.

[0009] In some embodiments, the interval between adjacent van der Waals material layers is 0.01 μm to 5 μm.

[0010] In some embodiments, the thickness of each van der Waals material layer is 0.4 μm to 2 μm.

[0011] In some embodiments, the van der Waals material having central inversion asymmetry includes at least one of rhombohedral boron nitride, transition metal chalcogenides, niobium oxide diiodide, niobium oxide dichloride, barium metaborate, and potassium fluoroboryllate.

[0012] In some embodiments, the driving assembly includes: a substrate, a cover plate, a rotating member, a power member, and a telescopic member;

[0013] The substrate and the cover plate are relatively spaced apart;

[0014] The cover plate is provided with a through slot, and the rotating member is nested in the through slot and can rotate in the through slot;

[0015] The surface of the rotating member facing the substrate and the surface of the substrate are both provided with oppositely arranged slots, and the two layers of the van der Waals material layers and the two layers of the distributed Bragg reflectors are respectively fixedly connected in the slots;

[0016] The power member is connected to the rotating member to control the rotation of the rotating member;

[0017] Two ends of the telescopic component are respectively connected to the cover plate and the substrate, and the telescopic component is used to adjust the distance between the cover plate and the substrate.

[0018] In some embodiments, gear teeth are provided on the side of the rotating member;

[0019] The driving member includes a rack and piezoelectric ceramics. The rack is engaged with the gear teeth, and one end of the rack is connected to the piezoelectric ceramics.

[0020] In some embodiments, the telescopic component includes a plurality of piezoelectric ceramics arranged at intervals, and two ends of the piezoelectric ceramics are respectively connected to the cover plate and the substrate.

[0021] In some embodiments, the drive assembly includes a sleeve and an optical fiber;

[0022] The sleeve includes a top and a raised portion, wherein the raised portion is arranged on the surface of the top to form a groove; the optical fiber is nested in the groove, and the optical fiber can rotate in the groove and move along the depth direction of the groove, and there is a gap between the top and the end of the optical fiber;

[0023] The optical fiber includes a core layer and a shell layer, and the two layers of distributed Bragg reflectors are respectively fixedly connected to the surface of the core layer facing the top and the surface of the top facing the optical fiber.

[0024] In some embodiments, a piezoelectric ceramic is connected to the surface of the optical fiber away from the top and / or a piezoelectric ceramic is connected to the surface of the top away from the optical fiber, for controlling the movement of the optical fiber along the depth direction of the groove.

[0025] In some embodiments, a lever perpendicular to the length direction of the optical fiber is fixedly connected to the outer surface of the shell layer away from the core layer, and the lever is used to control the rotation of the optical fiber in the groove.

[0026] In a second aspect, the present application provides a method for preparing a nonlinear optical crystal cavity, comprising the following steps:

[0027] Processing the van der Waals material with central inversion asymmetry into at least two stacked van der Waals material layers with a gap;

[0028] preparing an optical resonant cavity, the optical resonant cavity comprising two layers of distributed Bragg reflectors disposed opposite to each other, the distributed Bragg reflectors being disposed on the two outermost surfaces of the van der Waals material layer in a stacking direction;

[0029] A driving component is formed, wherein the driving component is connected to the van der Waals material layer, and the driving component is used to adjust the rotation angle between adjacent van der Waals material layers and the interval between adjacent van der Waals material layers.

[0030] In the above-mentioned nonlinear optical crystal cavity, a van der Waals material with central inversion asymmetry is used as the van der Waals material layer, and an optical resonant cavity is formed by respectively arranged on the two outermost surfaces in the stacking direction of the van der Waals material layer. At the same time, the driving component connected to the van der Waals material layer can be used to adjust the angle between adjacent van der Waals material layers and the spacing between adjacent van der Waals material layers. In actual use scenarios, by controlling the angle between two adjacent van der Waals material layers, the stacking angle of each layer of van der Waals material layers can be regulated so that the optical crystal can meet the phase matching conditions of different wavelengths, thereby realizing a nonlinear optical crystal cavity with adjustable function and wide-band working capability. At the same time, by controlling the distance between two adjacent van der Waals material layers, that is, the spacing of the optical resonant cavity, the resonant wavelength can be changed to achieve high nonlinear conversion efficiency at different wavelengths. The nonlinear optical crystal cavity of the present application has the ability to be adjustable function and wide-band working, and can achieve high nonlinear conversion efficiency at different wavelengths. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A schematic cross-sectional view of a nonlinear optical crystal cavity provided in one embodiment of the present application from a front view perspective;

[0032] Figure 2 A schematic diagram of a top view of a nonlinear optical crystal cavity provided in one embodiment of the present application;

[0033] Figure 3 A schematic cross-sectional view of a nonlinear optical crystal cavity provided in one embodiment of the present application from a front view perspective;

[0034] Figure 4 A schematic cross-sectional view of a nonlinear optical crystal cavity provided in an embodiment of the present application from a front view perspective.

[0035] Description of Reference Numerals

[0036] 1. Van der Waals material layer; 2. Distributed Bragg reflector; 31. Substrate; 32. Cover plate; 4. Rotating part; 5. Power part; 51. Rack; 52. Piezoelectric ceramic; 6. Telescopic part; 7. Sleeve; 71. Top; 72. Raised part; 8. Optical fiber; 81. Core layer; 82. Shell. DETAILED DESCRIPTION

[0037] To make the above-mentioned objects, features, and advantages of the present application more clearly understood, the specific embodiments of the present application are described in detail below. The following description sets forth many specific details to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways than those described herein, and those skilled in the art can make similar modifications without violating the scope of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0039] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0040] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of such features. In the description of this application, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0041] In this application, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0042] An embodiment of the present application provides a nonlinear optical crystal cavity, comprising:

[0043] At least two stacked van der Waals material layers 1 are provided with a gap therebetween, wherein the material of the van der Waals material layer 1 comprises a van der Waals material having central inversion asymmetry;

[0044] An optical resonant cavity, comprising two layers of distributed Bragg reflectors 2 arranged opposite to each other, the two layers of distributed Bragg reflectors 2 being respectively arranged on the two outermost surfaces in the stacking direction of the van der Waals material layer 1;

[0045] A driving component is connected to the van der Waals material layer 1 , and is used to adjust the rotation angle between adjacent van der Waals material layers 1 and the interval between adjacent van der Waals material layers 1 .

[0046] In the above-mentioned nonlinear optical crystal cavity, a van der Waals material with central inversion asymmetry is used as the van der Waals material layer 1, and an optical resonant cavity is formed by distributed Bragg reflectors 2 respectively arranged on the two outermost surfaces in the stacking direction of the van der Waals material layer 1. At the same time, the driving component connected to the van der Waals material layer 1 can be used to adjust the angle between adjacent van der Waals material layers 1 and the spacing between adjacent van der Waals material layers 1. In actual use scenarios, by controlling the angle between two adjacent van der Waals material layers 1, the stacking angle of each van der Waals material layer 1 can be regulated, so that the optical crystal can meet the phase matching conditions of different wavelengths, thereby realizing a nonlinear optical crystal cavity with adjustable function and wide-band working capability. At the same time, by controlling the distance between two adjacent van der Waals material layers 1, that is, the spacing of the optical resonant cavity, the resonant wavelength can be changed to achieve high nonlinear conversion efficiency at different wavelengths. The nonlinear optical crystal cavity of the present application has the ability to be adjustable function and wide-band working, and can also achieve high nonlinear conversion efficiency at different wavelengths.

[0047] Furthermore, traditional nonlinear optical crystals have low nonlinear coefficients and a high number of out-of-plane dangling bonds, which limits their application in miniaturized and integrated applications. Compared to traditional nonlinear optical crystals, van der Waals materials have significantly higher nonlinear coefficients and no out-of-plane dangling bonds, making them well-suited for miniaturized and integrated nonlinear optics.

[0048] It is understood that the van der Waals material having central inversion asymmetry includes at least one of rhombohedral boron nitride, transition metal chalcogenides, niobium oxide diiodide, niobium oxide dichloride, barium metaborate (BBO) and potassium fluoroborylbenzene (KBBF).

[0049] In some embodiments, the interval between adjacent van der Waals material layers 11 is 0.01 μm to 5 μm.

[0050] There is a strong van der Waals force between the van der Waals materials. When adjacent van der Waals material layers 11 are in contact or the spacing between adjacent van der Waals material layers 11 is too small, it is easy to cause the angle between adjacent van der Waals material layers 11 to be difficult to adjust. When the spacing between adjacent van der Waals material layers 11 is too large, it is easy to cause phase mismatch between the optical crystal and light of different wavelengths. It should be noted that within the range of the size of the spacing between the adjacent van der Waals material layers 11, the size of the spacing between adjacent van der Waals material layers 11 can be set according to the grain size and refractive index of different van der Waals materials. Optionally, the spacing between adjacent van der Waals material layers 11 is 0.01μm, 0.1μm, 0.5μm, 1μm, 1.5μm, 2μm, 2.5μm, 3μm, 3.5μm, 4μm, 4.5μm or 5μm. Alternatively, the spacing between adjacent van der Waals material layers 11 can also be within the range between the sizes of any two of the above spacings.

[0051] In some embodiments, the thickness of each van der Waals material layer 11 is 0.4 μm to 2 μm. Alternatively, the thickness of each van der Waals material layer 11 is 0.4 μm, 0.6 μm, 0.8 μm, 1 μm, 1.2 μm, 1.4 μm, 1.6 μm, 1.8 μm, or 2 μm. Alternatively, the thickness of each van der Waals material layer 11 may be within a range between any two of the aforementioned thicknesses.

[0052] In some embodiments, the material of each van der Waals material layer 11 includes rhombohedral boron nitride.

[0053] Reference Figure 1As shown, in some embodiments, the driving assembly includes: a substrate 31, a cover plate 32, a rotating member 4, a power member 5 and a telescopic member 6; the substrate 31 and the cover plate 32 are arranged relative to each other; a through groove is provided on the cover plate 32, and the rotating member 4 is nested in the through groove and can rotate in the through groove; the rotating member 4 is provided with oppositely arranged card grooves on the surface facing the substrate 31 and on the surface of the substrate 31, and two layers of van der Waals material layers 1 and two layers of distributed Bragg reflectors 2 are respectively fixedly connected in the card grooves; the power member 5 is connected to the rotating member 4 for controlling the rotation of the rotating member 4; the telescopic member 6 is arranged between the cover plate 32 and the substrate 31 and is connected to the cover plate 32 and the substrate 31, and the telescopic member 6 is used to adjust the distance between the cover plate 32 and the substrate 31.

[0054] Figure 1 The figure shows one specific embodiment of the drive assembly 2 of the present application. In this embodiment, the power member 5 drives the rotating member 4 to rotate within the through slot, thereby driving the van der Waals material layer 1 connected to the slot of the rotating member 4 to rotate relative to the van der Waals material layer 1 disposed on the substrate 31, thereby adjusting the rotation angle between the van der Waals material layers 1. At the same time, the telescopic member 6 can adjust the distance between the cover plate 32 and the substrate 31, thereby adjusting the spacing between adjacent van der Waals material layers 1.

[0055] Reference Figure 2 As shown, in some embodiments, gear teeth are provided on the side of the rotating member 4 ; the driving member includes a rack 51 and a piezoelectric ceramic 52 , the rack 51 is meshed with the gear teeth, and one end of the rack 51 is connected to the piezoelectric ceramic 52 .

[0056] The meshing rack 51 and gear teeth facilitate adjustment of the rotation angle of the rotating member 4. It is understood that the piezoelectric ceramic 52 is externally connected to a power source. By energizing the piezoelectric ceramic 52, its horizontal displacement can be controlled, thereby driving the movement of the rack 51, thereby driving the rotation of the rotating member 4, and thus adjusting the rotation angle between the van der Waals material layers 1.

[0057] In some embodiments, the substrate 31 includes at least one of a quartz substrate 31 , a glass substrate 31 , and a sapphire substrate 31 .

[0058] In some embodiments, the cover plate 32 includes at least one of a quartz cover plate 32 , a glass cover plate 32 , and a sapphire cover plate 32 .

[0059] In some embodiments, the rotating member 4 includes at least one of a quartz rotating member 4 , a glass rotating member 4 , and a sapphire rotating member 4 .

[0060] In some embodiments, the telescopic component 6 includes a plurality of piezoelectric ceramics arranged at intervals, and two ends of the piezoelectric ceramics are connected to the cover plate 32 and the substrate 31 respectively.

[0061] The expansion and contraction component 6 is formed by a plurality of piezoelectric ceramics arranged at intervals. By energizing the piezoelectric ceramics, the expansion and contraction of the piezoelectric ceramics in the longitudinal direction can be controlled, thereby controlling the interval between adjacent van der Waals material layers 1 .

[0062] Reference Figure 3 As shown, in some embodiments, the driving assembly includes a sleeve 7 and an optical fiber 8; the sleeve 7 includes a top 71 and a protrusion 72, and the protrusion 72 is arranged on the surface of the top 71 to form a groove; the optical fiber 8 is nested in the groove, and the optical fiber 8 can rotate in the groove and move along the depth direction of the groove, and there is a gap between the top 71 and the end of the optical fiber 8; the optical fiber 8 includes a core layer 81 and a shell layer 82, and two layers of distributed Bragg reflectors 2 are fixedly connected to the surface of the core layer 81 facing the top 71 and the surface of the top 71 facing the optical fiber 8, respectively.

[0063] Figure 3 One embodiment of a specific driving component of the present application is shown. In this embodiment, a group of van der Waals material layers 1 and distributed Bragg reflectors 2 are respectively connected by mutually nested light and tube caps, and the optical fiber 8 is nested in the groove. The optical fiber 8 can rotate in the groove and move along the depth direction of the groove, thereby being able to adjust the angle and spacing between adjacent van der Waals material layers 1.

[0064] In some embodiments, the material of the top portion 71 is at least one of quartz, glass, and sapphire.

[0065] In some embodiments, a piezoelectric ceramic is connected to the surface of the optical fiber 8 away from the top 71 to control the movement of the optical fiber 8 along the depth direction of the groove.

[0066] In some embodiments, a piezoelectric ceramic is connected to the surface of the top 71 away from the optical fiber 8 to control the movement of the optical fiber 8 along the depth direction of the groove.

[0067] In some embodiments, a lever perpendicular to the length direction of the optical fiber 8 is fixedly connected to the outer surface of the shell layer 82 away from the core layer 81, and the lever is used to control the rotation of the optical fiber 8 in the groove.

[0068] Reference Figure 4 As shown, in some embodiments, the sleeves 7 are multi-layered, and the raised portions 72 of the outer sleeves 7 surround the outer periphery of the inner sleeves 7. Furthermore, the sleeves 7 are slidably connected to each other, meaning that adjacent sleeves 7 can rotate relative to each other and move along the depth of the groove. It will be appreciated that no distributed Bragg reflector 2 is provided on the surface of the central van der Waals material. The above-described embodiments can realize a nonlinear optical crystal cavity comprising three or more stacked van der Waals material layers 1.

[0069] Another embodiment of the present application provides a method for preparing a nonlinear optical crystal cavity, comprising the following steps:

[0070] Processing the van der Waals material with central inversion asymmetry into at least two stacked van der Waals material layers 1 with a gap;

[0071] An optical resonant cavity is prepared, wherein the optical resonant cavity includes two layers of distributed Bragg reflectors 2 arranged opposite to each other, and the distributed Bragg reflectors 2 are respectively arranged on the two outermost surfaces of the van der Waals material layer 1 in the stacking direction;

[0072] A driving component is formed, which is connected to the van der Waals material layer 1 , and is used to adjust the rotation angle between adjacent van der Waals material layers 1 and the interval between adjacent van der Waals material layers 1 .

[0073] Example 1

[0074] Refer again Figures 1 and 2 As shown, in this embodiment, two pieces of rhombohedral boron nitride are used as the van der Waals material layer 1. Quartz material is selected as the substrate 31, the cover plate 32 and the rotating member 4. A groove with a diameter of 20 μm and a depth of 1 μm to 2 μm is opened at the center of the substrate 31 for filling the van der Waals material layer 1 and the distributed Bragg reflector 2. A through groove is opened at the center of the cover plate 32, and the rotating member 4 is embedded in the through groove. The upper end of the rotating member 4 has a gear, and the lower end of the rotating member 4, that is, on the surface facing the substrate 31, is opened with a groove with a diameter of 20 μm and a depth of 1 μm to 2 μm for filling the van der Waals material layer 1 and the distributed Bragg reflector 2. A rack 51 is also processed using quartz material. The specifications of the rack 51 match the gear teeth of the rotating part 4. One end of the rack 51 is connected to the stretched end of the piezoelectric ceramic 52. The piezoelectric ceramic 52 is fixed on the surface of the cover plate 32. The rack 51 is engaged with the gear teeth. By energizing the piezoelectric ceramic 52, the horizontal displacement of the rack 51 is controlled, thereby driving the rotating part 4 to rotate.

[0075] Example 2

[0076] Reference Figure 3As shown, in this embodiment, three pieces of rhombohedral boron nitride, each with a thickness of more than 800 nm, are selected as the van der Waals material layer 1. The optical fiber 8 is a multimode optical fiber 8 with an outer diameter of 125 μm and an inner diameter of 62.5 μm. The inner diameter of the raised portion 72 of the sleeve 7 is 128 μm. In this embodiment, when the optical fiber 8 or the sleeve 7 rotates relative to each other, the horizontal offset can be kept less than or equal to 3 μm. The raised portion 72 is set on the periphery of the optical fiber 8. The distributed Bragg reflector 2 and the van der Waals material layer 1 are transferred to the center position of the end face of the core layer 81 of the optical fiber 8, and the distributed Bragg reflector 2 and the van der Waals material layer 1 are transferred to the center position of the transparent material serving as the top 71. The top 71 is fixed to the raised portion 72 and the two layers of van der Waals material layers 1 are arranged relative to each other. A piezoelectric ceramic is connected to the side of the optical fiber 8 away from the sleeve 7 to adjust the movement of the optical fiber 8 in the extension depth direction within the groove of the sleeve 7. A lever is provided on the outer surface of the shell layer 82 away from the core layer 81 for controlling the rotation of the optical fiber 8 in the groove.

[0077] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0078] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art could make several modifications and improvements without departing from the spirit of the present application, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the patent in this application shall be based on the appended claims, and the specification and drawings may be used to interpret the claims.

Claims

1. A nonlinear optical crystal cavity, characterized in that: include: At least two stacked and spaced-apart van der Waals material layers, wherein the van der Waals material layers include a van der Waals material having central inversion asymmetry; An optical resonant cavity, comprising two layers of distributed Bragg reflectors arranged opposite to each other, the two layers of distributed Bragg reflectors being respectively arranged on the two outermost surfaces in the stacking direction of the van der Waals material layer; A driving component is connected to the van der Waals material layer, and the driving component is used to adjust the rotation angle between adjacent van der Waals material layers and the interval between adjacent van der Waals material layers.

2. The nonlinear optical crystal cavity according to claim 1, characterized in that: The interval between adjacent van der Waals material layers is 0.01 μm to 5 μm.

3. The nonlinear optical crystal cavity according to claim 1, characterized in that: The thickness of each van der Waals material layer is 0.4 μm to 2 μm.

4. The nonlinear optical crystal cavity according to claim 1, characterized in that: The van der Waals material with central inversion asymmetry includes at least one of rhombohedral boron nitride, transition metal chalcogenides, niobium oxide diiodide, niobium oxide dichloride, barium metaborate and potassium fluoroboroboryllium.

5. The nonlinear optical crystal cavity according to any one of claims 1 to 4, characterized in that: The driving assembly includes: a substrate, a cover plate, a rotating part, a power part and a telescopic part; The substrate and the cover plate are relatively spaced apart; The cover plate is provided with a through slot, and the rotating member is nested in the through slot and can rotate in the through slot; The surface of the rotating member facing the substrate and the surface of the substrate are both provided with oppositely arranged slots, and the two layers of the van der Waals material layers and the two layers of the distributed Bragg reflectors are respectively fixedly connected in the slots; The power member is connected to the rotating member to control the rotation of the rotating member; Two ends of the telescopic component are respectively connected to the cover plate and the substrate, and the telescopic component is used to adjust the distance between the cover plate and the substrate.

6. The nonlinear optical crystal cavity according to claim 5, characterized in that: The side surface of the rotating member is provided with gear teeth; The driving member includes a rack and piezoelectric ceramics. The rack is engaged with the gear teeth, and one end of the rack is connected to the piezoelectric ceramics.

7. The nonlinear optical crystal cavity according to claim 5, characterized in that: The telescopic component includes a plurality of piezoelectric ceramics arranged at intervals, and two ends of the piezoelectric ceramics are respectively connected to the cover plate and the substrate.

8. The nonlinear optical crystal cavity according to any one of claims 1 to 4, characterized in that: The driving assembly includes a sleeve and an optical fiber; The sleeve includes a top and a raised portion, wherein the raised portion is arranged on the surface of the top to form a groove; the optical fiber is nested in the groove, and the optical fiber can rotate in the groove and move along the depth direction of the groove, and there is a gap between the top and the end of the optical fiber; The optical fiber includes a core layer and a shell layer, and the two layers of distributed Bragg reflectors are respectively fixedly connected to the surface of the core layer facing the top and the surface of the top facing the optical fiber.

9. The nonlinear optical crystal cavity according to claim 8, characterized in that: A piezoelectric ceramic is connected to the surface of the optical fiber away from the top and / or a piezoelectric ceramic is connected to the surface of the top away from the optical fiber, for controlling the movement of the optical fiber along the depth direction of the groove; and / or, A shifting rod perpendicular to the length direction of the optical fiber is fixedly connected to the outer surface of the shell layer away from the core layer, and the shifting rod is used to control the rotation of the optical fiber in the groove.

10. A method for preparing a nonlinear optical crystal cavity, characterized in that: The steps include: Processing the van der Waals material with central inversion asymmetry into at least two stacked van der Waals material layers with a gap; preparing an optical resonant cavity, the optical resonant cavity comprising two layers of distributed Bragg reflectors disposed opposite to each other, the distributed Bragg reflectors being disposed on the two outermost surfaces of the van der Waals material layer in a stacking direction; A driving component is formed, wherein the driving component is connected to the van der Waals material layer, and the driving component is used to adjust the rotation angle between adjacent van der Waals material layers and the interval between adjacent van der Waals material layers.

Images