A high-efficiency solid-state magnetometer exciting NV color centers and a preparation method thereof

Abstract

The present application relates to a kind of high-efficiency solid-state magnetometer of exciting NV color center and its preparation method, belong to the preparation technical field of solid-state magnetometer.The solid-state magnetometer of the present application replaces traditional objective with adjustable focus fresnel zone plate S1, to realize the collimation focusing of excitation laser, its focal length can be adjusted by electric control;At the same time, superstructure S3 is made on the surface of diamond with NV color center, to realize the further concentration of microwave energy;In addition, by M / NEMS method, bevel is formed on the sidewall of diamond, and is plated with composite film structure, while realizing high reflection of fluorescence, the high reflection film is effectively protected.Therefore, the NV color center in the high-efficiency solid-state magnetometer of exciting NV color center of the present application is under the dual action of laser and magnetic field, realizes the microstructure of high-efficiency excitation, collection of fluorescence, to overcome the problems of current NV color center magnetometer, such as large volume, low integration level and low efficiency.

Description

Technical Field

[0001] This invention belongs to the field of solid-state magnetometer fabrication technology, and relates to a solid-state magnetometer that efficiently excites NV color centers and its fabrication method. Background Technology

[0002] Solid-state magnetometers based on NV color centers are a novel, multidisciplinary technology integrating quantum technology, optoelectronic information technology, micro-nano technology, microwave technology, and signal processing technology. They enable ultra-high precision detection of weak magnetic vectors, exhibiting high sensitivity and high spatial resolution in weak magnetic detection. Furthermore, NV atomic magnetometers possess significant potential advantages, including long spin coherence time, small size, fast start-up speed, wide operating temperature range, and high stability. In addition, NV color center-based solid-state magnetometers can achieve a resolution of up to 40 nm in biomedical imaging, far exceeding the current highest resolution of 120 nm for optical near-field imaging.

[0003] The basic principle of a solid-state magnetometer based on NV centers is as follows: NV centers generate fluorescence upon excitation by a 532nm wavelength laser. The fluorescence spectrum, modulated by a 2.87GHz microwave, displays electron spin resonance. Under different magnetic field environments, the degree of Zeeman splitting of the electron spin resonance reflects the vector information of the magnetic field. Based on this physical principle, weak magnetic fields can be detected through related optical excitation and collection. Several patents, such as CN108983121 A and CN108732518A, have discussed this topic. While significant research has been conducted, their excitation and collection processes suffer from drawbacks such as large size, low integration, and low efficiency.

[0004] Therefore, further improvements are needed to the existing solid-state magnetometers with NV color centers to solve the technical problems existing in the current technology. Summary of the Invention

[0005] In view of this, one objective of the present invention is to provide a solid-state magnetometer that efficiently excites NV color centers; another objective of the present invention is to provide a method for preparing a solid-state magnetometer that efficiently excites NV color centers.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] 1. A solid-state magnetometer for efficiently exciting NV color centers, the solid-state magnetometer comprising a tunable Fresnel zone plate S1, an improved diamond with an NV color center structure, and a photodetector S5, wherein the improved diamond with an NV color center structure S2 is formed by growing a metasurface structure S3 and a microwave coupled antenna S4 on the surface of the diamond with an NV color center structure S2.

[0008] The upper surface S of the diamond S2 with NV color center structure22 The area is smaller than the lower surface S 25 The area of ​​the four oblique surfaces (S 21 All of them have sloping sidewalls, wherein the upper surface of the diamond (S2) with NV color center structure is covered with a bottom layer of fluorescent high reflective film and a surface laser high transmittance film, and the side surface of the diamond S2 with NV color center structure is covered with a bottom layer of fluorescent high reflective film and a surface fluorescent protective film.

[0009] During the use of the solid-state magnetometer, after the laser is focused through the adjustable Fresnel zone plate S1, it is modulated by the microwave coupling antenna S4 and incident on the upper surface of the improved diamond S2 with NV color center structure. Under the modulation of the microwave coupling antenna S4 and the action of the magnetic field, the generated fluorescence is focused on the photodetector S5, and the relevant parameters of the magnetic intensity are read according to the information of the fluorescence signal.

[0010] Preferably, in the adjustable-focus Fresnel zone plate S1, L1 and L3 form a cantilever beam in the Y direction, forming corresponding pads pad1 and pad3; L2 and L4 form a cantilever beam in the X direction, with corresponding pads pad2 and pad4.

[0011] The adjustable-focus Fresnel zone plate S1 can be driven by piezoelectric, electrostatic adsorption, or electromagnetic methods.

[0012] More preferably, the tunable Fresnel zone plate S1 is prepared according to the following steps:

[0013] Polycrystalline silicon thin films (α-Si) are grown on quartz glass substrates using plasma-enhanced chemical vapor deposition (PECVD), and then tunable Fresnel zone plates S1 are formed using N / MEMS methods.

[0014] Preferably, the diamond S2 with the NV color center structure is prepared according to the following method:

[0015] Atomic deposition (ALD) was used to deposit S on the upper surface of diamond. 22 To grow material I, a composite film S is formed on the upper surface. 23 To increase laser transmittance and fluorescence reflectivity; on the lower surface S of the diamond 25 Growth material I forms a lower surface composite film S 26 (Its main function is to allow efficient transmission of fluorescence while effectively filtering out other stray light); on the oblique side S of the diamond 21 Materials II and III were grown using atomic deposition (ALD) to form a high-reflectivity film (to give it high reflectivity for fluorescence) and a protective film (to enhance the oxidation resistance of the high-reflectivity film), respectively, to form a composite film with oblique sides. 24 This yields diamond S2 with an NV color center structure;

[0016] Material I is any one of Ta2O5 or SiO2, material II is any one of Cr, Cu, Ag or Al2O3, and material III is SiO2.

[0017] Preferably, the improved diamond with NV color center structure is prepared according to the following steps:

[0018] (1) Growth of a superstructure S3 on the surface of diamond S2 with NV color center structure: Using the diamond S2 with NV color center structure as a substrate, firstly, photoresist is spin-coated and patterned on the upper surface, and a thin film material with a refractive index greater than or equal to TiO2 is grown by physical vapor deposition (PVD). Then, the thin film material is patterned by liftoff method to form several superatoms (the superatomic structure can achieve efficient microwave coupling, thereby maximizing fluorescence excitation while reducing microwave power). Finally, the superstructure S3 is grown on the surface of diamond S2 with NV color center structure.

[0019] (2) Preparation of improved diamond with NV center structure: Using the product of growing metasurface structure S3 on the surface of diamond S2 with NV center structure in step (1) as a substrate, first spin-coating photoresist and patterning is performed on the upper surface without metasurface structure S3, and then growing metal material S by physical vapor deposition (PVD) or electron beam evaporation. 41 Then, the metal thin film is patterned in the non-metasurface structure region by lifting off to form a microwave-coupled antenna S4, thereby forming an improved diamond with an NV color center structure having a metasurface structure S3 and a microwave-coupled antenna S4 on the surface.

[0020] More preferably, the thin film material is any one of TiO2, ZnSn, or α-Si.

[0021] More preferably, the microwave coupling antenna (S4) is strip-shaped or ring-shaped.

[0022] More preferably, the metal material is copper.

[0023] 2. The preparation method of the above-mentioned solid-state magnetometer, wherein the preparation method includes the following steps:

[0024] (1) Using the photodetector S5, the improved diamond with the NV color center structure on the surface of the superstructure S3 is precisely positioned by flip-chip bonding and seamlessly connected to the photodetector S5. Then the connected product is fixed in an aluminum alloy bracket with precision positioning holes.

[0025] (2) The adjustable-focus Fresnel zone plate S1 is fixed by the precision positioning hole on the aluminum alloy bracket. The lens focal length in the adjustable-focus Fresnel zone plate S1 is coarsely adjusted by adjusting the height by tap, and the lens focal length in the adjustable-focus Fresnel zone plate S1 is finely adjusted by the electronic control unit to form a solid-state magnetometer that efficiently excites NV color centers.

[0026] Preferably, the photodetector S5 is made of a photodiode;

[0027] The photodiode is an FDS1010.

[0028] The beneficial effects of this invention are as follows: This invention discloses a high-efficiency solid-state magnetometer for exciting NV centers. The solid-state magnetometer includes a tunable-focus Fresnel zone plate S1, an improved diamond with an NV center structure S2, a metasurface structure S3 containing the improved diamond S2 surface with an NV center structure, a microwave-coupled antenna S4, and a photodetector S5. The solid-state magnetometer of this invention uses a tunable-focus Fresnel zone plate S1 instead of a traditional objective lens to achieve collimation and focusing of the excitation laser; its focal length can be adjusted electronically. Simultaneously, a metasurface structure S3 is fabricated on the surface of the diamond with NV centers to further concentrate microwave energy. Furthermore, an inclined surface is formed on the sidewall of the diamond using the M / NEMS method, and a composite film structure is deposited, effectively protecting the high-reflectivity film while achieving high fluorescence reflectivity. Therefore, based on the M / NEMS method and micro-assembly, this invention introduces a tunable-focus Fresnel zone plate S1, and simultaneously introduces a metasurface structure and a diamond sidewall oblique ultra-fine processing method within the intrinsic body of the NV color center. This concentrates laser and microwave energy, achieving efficient excitation of the NV color center and efficient collection of fluorescence, thus achieving the miniaturized integration of a solid-state magnetometer based on efficient excitation and collection of NV color centers. In the solid-state magnetometer of this invention, the NV color center achieves efficient fluorescence excitation and collection under the dual action of laser and magnetic field, overcoming the problems of large size, low integration, and low efficiency of current NV color center magnetometers.

[0029] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0030] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein:

[0031] Figure 1This is a flowchart illustrating the fabrication process of the adjustable-focus Fresnel zone plate S1 of the present invention.

[0032] Figure 2 This is a structural diagram of the adjustable-focus Fresnel zone plate S1 of the present invention;

[0033] Figure 3 Four oblique lateral surfaces S are formed on diamond S2 with an NV color center structure. 21 process;

[0034] Figure 4 This is a structural diagram of diamond S2 with NV color center structure according to the present invention, where a is a top view and b is a cross-sectional view;

[0035] Figure 5 This is a structural diagram of the supertable structure S3 of the present invention, where a is a top view and b is a cross-sectional view;

[0036] Figure 6 This is a structural diagram of the microwave coupling antenna S4 of the present invention, wherein a is a top view of the strip microwave coupling antenna, b is a top view of the ring microwave coupling antenna, and c is a cross-sectional view of the microwave coupling antenna;

[0037] Figure 7 The structural diagram shows the solid-state magnetometer with high efficiency for exciting NV color centers prepared in this invention.

[0038] S1 is an adjustable Fresnel zone plate, and S2 is a diamond with an NV color center structure (S 21 S-shaped side 22 For the upper surface, S 23 For the upper surface composite film, S 24 Slanted side composite membrane, S 25 For the lower surface, S 26 S3 is the lower surface composite film, S4 is the superstructure, S5 is the microwave coupled antenna, and S6 is the photodetector. Detailed Implementation

[0039] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0040] Example 1

[0041] The fabrication of a highly efficient solid-state magnetometer for exciting NV centers mainly includes the following steps:

[0042] 1. Preparation of tunable Fresnel zone plate S1: The preparation process is as follows Figure 1 As shown, a 300µm thick quartz glass substrate is used as the substrate, and grooves of 3-5µm are etched to form the substrate. A polycrystalline silicon thin film (α-Si) with a thickness of 300-500nm is grown by plasma-enhanced chemical vapor deposition (PECVD). Then, a zone ring is formed by dry etching using surface microscopy (N / MEMS). Simultaneously, metal is grown and patterned to form driving electrodes pad1-pad4, and structural release forms cantilever beams L1-L4, forming a tunable Fresnel zone plate S1 (its structure is shown in the figure). Figure 2 As shown, L1 and L3 form a cantilever beam in the Y direction, with corresponding pads pad1 and pad3; L2 and L4 form a cantilever beam in the X direction, with corresponding pads pad2 and pad4; the adjustable Fresnel zone plate S1 can be driven by any of piezoelectric, electrostatic adsorption, or electromagnetic methods. The system is debugged by adjusting the focal length through an external voltage to ensure that the laser focal spot can accurately fall on the NV color center surface.

[0043] 2. Preparation of diamond S2 with NV color center structure: (1) The side surface of the diamond with NV color center structure is subjected to oblique ultrafine processing. Laser ablation, grinding and polishing processes are used to form four oblique side surfaces S on the diamond with NV color center structure. 21 (like Figure 3 (as shown); (2) the above-mentioned upper surface S is deposited by atomic deposition (ALD). 22 To grow Ta2O5 or SiO2 materials to form a composite film on the upper surface S 23 To increase the transmittance of the laser and the high reflectivity of the fluorescence; (3) on the lower surface S mentioned above 25 Growth of Ta2O5 or SiO2 materials to form a lower surface composite film S 26 (Its main function is that fluorescence can be efficiently transmitted and other stray light can be effectively filtered out); (4) on the oblique side surface S of the diamond 21 A high-reflectance film (using any one of Cr, Cu, Ag, Al2O3, or SiO2 to provide high fluorescence reflectivity) and a protective film (using SiO2 to enhance the oxidation resistance of the high-reflectance film) are formed by growing a high-reflectance film material and a SiO2 material respectively using atomic deposition (ALD) to grow high-reflectance film material and SiO2 material respectively. These are then combined to form a beveled-side composite film S. 24 Thus, diamond S2 with an NV color center structure (its structure is as follows) is obtained. Figure 4 As shown in the figure (where a is a top view and b is a cross-sectional view), the upper surface S of the diamond S2 with the NV color center structure is... 22 The area is smaller than the lower surface S 25 The area of ​​the four oblique sides S21 All have sloping sidewalls. The upper surface of the improved diamond S2 with NV color center structure is covered with a bottom fluorescent high reflective film and a surface laser high transmittance film. The side surface of the improved diamond S2 with NV color center structure is covered with a bottom fluorescent high reflective film and a surface fluorescent protective film.

[0044] 3. Fabrication of a metasurface structure S3 on diamond S2 with an NV color center structure: Using diamond S2 with an NV color center structure as a substrate, photoresist is spin-coated and patterned on the upper surface. A thin film material with a refractive index greater than or equal to TiO2 is grown by physical vapor deposition (PVD). Then, the thin film material is patterned by a liftoff method to form several superatoms (this superatomic structure can achieve efficient microwave coupling, thereby maximizing fluorescence excitation while reducing microwave power). Finally, a metasurface structure S3 is grown on the surface of diamond S2 with an NV color center structure (its structure is as follows). Figure 5 As shown in the figure, where a is the top view and b is the cross-sectional view.

[0045] 4. Continue to fabricate microwave-coupled antennas S4 on diamond S2 with NV color center structure to form an improved diamond with NV color center structure: Using diamond S2 with NV color center structure and surface-grown metasurface structure S3 as a substrate, first spin-coat photoresist and pattern it on the surface without metasurface structure S3. Then, grow a strip-shaped or ring-shaped metal material (where the refractive index of the metal material is greater than or equal to TiO2, such as copper) by physical vapor deposition (PVD). Then, pattern it by liftoff to form microwave-coupled antenna S4, thereby forming an improved diamond with NV color center structure with surface metasurface structure S3 and microwave-coupled antenna S4 (its structure is as follows). Figure 6 As shown, a is a top view of the strip microwave coupled antenna, b is a top view of the loop microwave coupled antenna, and c is a cross-sectional view of the microwave coupled antenna.

[0046] 5. Preparation of a solid-state magnetometer with high efficiency for exciting NV color centers: (1) Using the photodetector S5 as a photodetector, the improved diamond with the superstructure S3 on the surface is precisely positioned by flip-chip bonding and seamlessly connected to the photodetector S5. Then, the connected product is fixed in an aluminum alloy bracket with a precision positioning hole.

[0047] (2) The adjustable-focus Fresnel zone plate S1 is fixed through the precision positioning holes of the aluminum alloy bracket. The height is adjusted by tapping to achieve coarse adjustment of the lens focal length in the adjustable-focus Fresnel zone plate S1. The lens focal length of the adjustable-focus Fresnel zone plate S1 is finely adjusted by the electronic control unit to form a solid-state magnetometer that efficiently excites NV color centers (structure as shown). Figure 7 (As shown).

[0048] In the use of the high-efficiency solid-state magnetometer with NV center excitation prepared in this invention, the laser light is focused through a tunable Fresnel zone plate S1, modulated by a microwave coupling antenna S4, and incident on the upper surface of the improved diamond S2 with NV center structure. Under the modulation of the microwave coupling antenna S4 and the action of the magnetic field, the generated fluorescence is focused onto the photodetector S5. The relevant parameters of the magnetic intensity are read based on the information of the fluorescence signal. The working principle of the high-efficiency solid-state magnetometer with NV center excitation prepared in this invention is as follows: a 532nm wavelength laser light is collimated and focused through S1 to a depth of 30-50µm on the diamond surface. A 2.87GHz microwave light is coupled to S2 through S4. Due to the effect of S3, the microwave light is more concentrated at the focal spot of the laser light. Under the action of the magnetic field, fluorescence is generated in S2 containing NV centers. This fluorescence acts on the surface of the diamond. 23 and S 24 Total internal reflection occurs after passing through the S-channel, and the vast majority of the fluorescence passes through the S-channel. 26 Then it enters S5, and after passing through the signal detection circuit, the magnetic field information is read out.

[0049] In summary, this invention discloses a highly efficient solid-state magnetometer for exciting NV centers. The solid-state magnetometer comprises a tunable-focus Fresnel zone plate S1, an improved diamond with an NV center structure S2, a metasurface structure S3 containing the improved diamond S2 surface with an NV center structure, a microwave-coupled antenna S4, and a photodetector S5. The solid-state magnetometer of this invention uses a tunable-focus Fresnel zone plate S1 instead of a traditional objective lens to achieve collimation and focusing of the excitation laser; its focal length can be adjusted electronically. Simultaneously, a metasurface structure S3 is fabricated on the surface of the diamond with NV centers to further concentrate microwave energy. Furthermore, an inclined surface is formed on the sidewall of the diamond using the M / NEMS method, and a composite film structure is deposited to achieve high fluorescence reflectivity while effectively protecting the high-reflectivity film. Therefore, based on the M / NEMS method and micro-assembly, this invention introduces a tunable-focus Fresnel zone plate S1, and simultaneously introduces a metasurface structure and a diamond sidewall oblique ultra-fine processing method within the intrinsic body of the NV color center. This concentrates laser and microwave energy, achieving efficient excitation of the NV color center and efficient collection of fluorescence, thus achieving the miniaturized integration of a solid-state magnetometer based on efficient excitation and collection of NV color centers. In the solid-state magnetometer of this invention, the NV color center achieves efficient fluorescence excitation and collection under the dual action of laser and magnetic field, overcoming the problems of large size, low integration, and low efficiency of current NV color center magnetometers.

[0050] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A solid-state magnetometer for efficiently exciting NV color centers, characterized in that, The solid-state magnetometer includes a tunable Fresnel zone plate (S1), an improved diamond with an NV center structure, and a photodetector (S5), wherein the improved diamond with an NV center structure (S2) is formed by growing a metasurface structure (S3) and a microwave-coupled antenna (S4) on the surface of the diamond with an NV center structure (S2). The upper surface (S) of the diamond (S2) with the NV color center structure 22 The area of ​​the surface is smaller than that of the lower surface (S). 25 The area of ​​the four oblique surfaces (S) 21 All of them have sloping sidewalls, wherein the upper surface of the diamond (S2) with NV color center structure is covered with a bottom layer of fluorescent high reflective film and a surface laser high transmittance film, and the side surface of the diamond (S2) with NV color center structure is covered with a bottom layer of fluorescent high reflective film and a surface fluorescent protective film. During the use of the solid-state magnetometer, the laser is focused through the adjustable Fresnel zone plate (S1), modulated by the microwave coupling antenna (S4), and incident on the upper surface of the improved diamond (S2) with NV color center structure. Under the modulation of the microwave coupling antenna (S4) and the action of the magnetic field, the generated fluorescence is focused on the photodetector (S5), and the relevant parameters of the magnetic intensity are read based on the information of the fluorescence signal.

2. The solid-state magnetometer according to claim 1, characterized in that, In the adjustable-focus Fresnel zone plate (S1), L1 and L3 form a cantilever beam in the Y direction, with corresponding pads pad1 and pad3; L2 and L4 form a cantilever beam in the X direction, with corresponding pads pad2 and pad4. The adjustable-focus Fresnel zone plate (S1) can be driven by piezoelectric, electrostatic adsorption or electromagnetic methods.

3. The solid-state magnetometer according to claim 2, characterized in that, The adjustable-focus Fresnel zone plate (S1) is prepared according to the following steps: Polycrystalline silicon thin films were grown on quartz glass substrates using plasma-enhanced chemical vapor deposition, and then tunable Fresnel zone plates (S1) were formed using the N / MEMS method.

4. The solid-state magnetometer according to claim 1, characterized in that, The diamond (S2) with the NV color center structure is prepared according to the following method: Atomic deposition is used to deposit diamond on the upper surface (S). 22 ) to grow material I to form a composite film on the upper surface (S) 23 To increase laser transmittance and fluorescence reflectivity; on the lower surface of the diamond (S) 25 Growth material I forms a lower surface composite film (S) 26 ); on the oblique side (S) of the diamond 21 Materials II and III are grown using atomic deposition to form a high-reflectivity film and a protective film, respectively, which are then combined to form a beveled composite film (S). 24 Thus, diamond (S2) with an NV color center structure is obtained; Material I is any one of Ta2O5 or SiO2, material II is any one of Cr, Cu, Ag or Al2O3, and material III is SiO2.

5. The solid-state magnetometer according to claim 1, characterized in that, The improved diamond with NV center structure is prepared according to the following steps: (1) Growth of a meta-structure (S3) on the surface of diamond with NV color center structure (S2): Using the diamond with NV color center structure (S2) as a substrate, photoresist is first spin-coated and patterned on the upper surface. A thin film material with a refractive index greater than or equal to TiO2 is grown by physical vapor deposition. Then, the thin film material is patterned by a lift-off method to form several superatoms, and finally, a meta-structure (S3) is grown on the surface of diamond with NV color center structure (S2). (2) Preparation of improved diamond with NV color center structure: Using the product of growing a metasurface structure (S3) on the surface of diamond with NV color center structure (S2) in step (1) as a substrate, first spin-coating photoresist and patterning is performed on the upper surface without metasurface structure (S3), and then growing a metal material (S3) by physical vapor deposition or electron beam evaporation. 41 Then, a microwave-coupled antenna (S4) is formed by patterning a metal thin film in the non-metasurface structure region through a peeling method, thereby forming an improved diamond with an NV color center structure having a metasurface structure (S3) and a microwave-coupled antenna (S4) on the surface.

6. The solid-state magnetometer according to claim 5, characterized in that, The thin film material is any one of TiO2, ZnSn, or α-Si.

7. The solid-state magnetometer according to claim 5, characterized in that, The microwave coupling antenna (S4) is either strip-shaped or ring-shaped.

8. The solid-state magnetometer according to claim 5, characterized in that, The metallic material is copper.

9. The method for preparing a solid-state magnetometer according to any one of claims 1 to 8, characterized in that, The preparation method includes the following steps: (1) Using the photodetector (S5), the improved diamond with the superstructure (S3) on the surface is precisely positioned by flip-chip bonding and seamlessly connected to the photodetector (S5). Then the connected product is fixed in an aluminum alloy bracket with precision positioning holes. (2) The adjustable-focus Fresnel zone plate (S1) is fixed by the precision positioning hole on the aluminum alloy bracket. The lens focal length in the adjustable-focus Fresnel zone plate (S1) is coarsely adjusted by adjusting the height by tap, and the lens focal length of the adjustable-focus Fresnel zone plate (S1) is finely adjusted by the electronic control unit to form a solid-state magnetometer that efficiently excites NV color centers.

10. The preparation method according to claim 9, characterized in that, The photodetector (S5) is made of a photodiode; The photodiode is an FDS1010.

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