Solid spin sensing structure based on curing adhesive and quantum magnetometer

Abstract

The invention relates to the technical field of quantum precision measurement, and provides a solid spin sensing structure based on curing glue and a quantum magnetometer, the solid spin sensing structure comprises a diamond block, a tip optical fiber, a microwave radiator and a first photoelectric detection module; the photoinduced fluorescence is gathered through the curing adhesive in a special form, the optical density of the photoinduced fluorescence is improved, efficient collection of the photoinduced fluorescence is achieved in a limited space, the magnetic field measurement bandwidth and the response speed are effectively improved in combination with the ODMR measurement technology, meanwhile, loss of the photoinduced fluorescence caused by total internal reflection can be reduced, the manufacturing cost is low, and the application range is wide. And the method is suitable for small-size integration and batch manufacturing.

Description

Technical Field

[0001] This invention relates to the field of quantum precision measurement technology, specifically to a solid-state spin sensing structure based on a curing adhesive and a quantum magnetometer. Background Technology

[0002] In recent years, research on solid-state spin color center systems in the field of quantum precision has developed rapidly, especially in the research on magnetic field detection. The detection method based on optically detected magnetic resonance (ODMR) has been developed. By studying the linear relationship between the magnetic resonance frequency and the external magnetic field, the sensing, measurement and quantification of the external magnetic field can be realized.

[0003] Diamond NV color center magnetometers are used in fields such as power and non-destructive testing for their high stability. Currently, there is a demand for high bandwidth and high sampling rate. However, the structure of a typical high bandwidth magnetometer is large, which is not conducive to small-volume integration and mass production. Summary of the Invention

[0004] This invention proposes a solid-state spin sensing structure and quantum magnetometer based on a curing adhesive. By using a special morphology of the curing adhesive, the fluorescence generated by the NV color center of diamond is aggregated, thereby improving the fluorescence density. Combined with ODMR measurement technology, the magnetic field measurement bandwidth and response speed are effectively improved. Moreover, the combination of the curing adhesive and the diamond block has low cost and is simple to manufacture, making it suitable for small-volume integration and mass production of probe devices.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A solid-state spin sensing structure based on a curable adhesive, comprising: - A diamond block containing an ensemble NV color center, comprising a first facet and a second facet, wherein the second facet is provided with a first-shaped cured adhesive, which is used to gather and output light propagating outward from the second facet; - A terminal optical fiber, comprising a first end and a second end, the first end being used to load external excitation light, and the second end being configured to input the excitation light from the first surface into the diamond block; - A microwave radiator, used to load external microwave signals and radiate them onto the diamond block; - A first photoelectric detection module, located near the second surface, is used to collect the photoluminescence output by the diamond block.

[0006] In a preferred design of the solid-state spin sensing structure described above, the microwave radiator is a coplanar waveguide.

[0007] In a preferred design of the solid-state spin sensing structure described above, there are also several light reflectors positioned close to the diamond block to guide some of the light propagating outward from the non-second surface toward the first photodetector module. Furthermore, the surface of the diamond block facing the light reflectors has a second type of cured adhesive.

[0008] In a preferred design of the solid-state spin sensing structure described above, a second photodetector module for acquiring reference signals is also included. This second photodetector module is located on the third face of the diamond block, which is opposite to the first face. The second photodetector module is used to acquire the excitation light output through the third face.

[0009] In a preferred design of the solid-state spin sensing structure described above, the third surface has a third-morphology cured adhesive used to gather and output light propagating outward from the third surface.

[0010] In the solid-state spin sensing structure described above, in a preferred design, the refractive index of the cured adhesive is not less than 1.5.

[0011] In a preferred design of the solid-state spin sensing structure described above, the cured adhesive does not produce photoluminescence under excitation light. Furthermore, the cured adhesive is a cured product of hydrogenated silicon silsesquioxane photoresist, polysiloxane photoresist, organosilane photoresist, polyimide photoresist, or benzocyclobutene photoresist.

[0012] Another aspect of this application also describes a quantum magnetometer for measuring the magnetic field strength and direction of a magnetic field to be measured, having at least one solid-state spin sensing structure as described above.

[0013] Compared with the prior art, the beneficial effects of the present invention are: the aggregation of photoluminescence is achieved by using a special type of curing adhesive, which improves the optical density of photoluminescence, and achieves efficient collection of photoluminescence in a confined space. Combined with ODMR measurement technology, it effectively improves the magnetic field measurement bandwidth and response speed. At the same time, it can reduce the loss of photoluminescence due to total internal reflection, and has low manufacturing cost, making it suitable for small-volume integration and mass production. Attached Figure Description

[0014] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a schematic diagram of the solid-state spin sensing structure in Example 1; Figure 2 This is a four-axis schematic diagram of the ensemble NV color center; Figure 3 This is a schematic diagram of the solid-state spin sensor structure with a light reflector in Embodiment 1; Figure 4 This is a schematic diagram of the end face of the terminal optical fiber in Example 1, which is a spherical lens structure. Figure 5 This is a schematic diagram of the spherical lens structure coated with a reflective film in Example 1; Figure 6 This is a schematic diagram of the sensing structure in Example 1 with the polarization direction perpendicular to the

[111] crystal orientation; Figure 7 This is a schematic diagram of the differential scheme for the solid-state spin sensing structure in Example 2; Figure 8 This is a schematic diagram of the layout design of the cured adhesive in the third form of Example 2; Figure 9 This is a system block diagram of the quantum magnetometer in Example 3. Detailed Implementation

[0016] The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0017] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, one or more embodiments are now described with reference to the accompanying drawings, wherein similar reference numerals are used throughout the text to refer to similar components. In the following description, numerous specific details are set forth for purposes of explanation in order to provide a more thorough understanding of one or more embodiments. However, it will be apparent that one or more embodiments may be practiced in various circumstances without these specific details, and the various embodiments may be combined with and referenced to each other without contradiction.

[0018] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0019] A diamond NV center (nitrogen-vacancy center) is an atomic-level defect in the diamond lattice, formed by a nitrogen atom (N) replacing a carbon atom and combining with its adjacent vacancy (V). It is one of the most studied solid-state spin center systems due to its superior quantum properties at room temperature, making it a core platform for quantum sensing, quantum computing, and quantum communication.

[0020] The core principle of ODMR (Optically Probe Magnetic Resonance) is to initialize the spin state of the NV color center to the m_s=0 ground state using a green laser, while simultaneously applying a tunable microwave. When the microwave frequency precisely matches the energy level difference between the m_s=0 and m_s=±1 states, a resonant transition occurs, flipping part of the spin to the m_s=±1 state. Since the red fluorescence intensity emitted by the NV color center in the m_s=0 state is significantly stronger than that in the m_s=±1 state, the fluorescence intensity detected at the resonance frequency will decrease. By scanning the microwave frequency and monitoring this decrease in fluorescence intensity (i.e., the "resonance valley"), highly sensitive optical detection and magnetic resonance spectroscopy measurement of its electronic spin state can be achieved. This is the basis for its high-precision sensing of physical quantities such as magnetic fields.

[0021] Example 1 See appendix Figure 1 As an initial design, this example proposes a solid-state spin sensing structure based on fused spherical lens fiber, including a diamond block 1, a terminal fiber 2, a microwave radiator 3, and a first photoelectric detection module 4.

[0022] In this example, diamond block 1 contains ensemble NV color centers (meaning a large number of NV color centers) and includes a first face 11 and a second face 12. The second face 12 has a first-form curing adhesive 121, which is used to focus and output light propagating outward from the second face 12. For ease of understanding, in this example, diamond block 1 is a cuboid block structure, with the first face 11 being its side near the terminal optical fiber 2, and the second face 12 being the top face of diamond block 1. Regarding the first-form curing adhesive 121, its function is described as primarily used for focusing photofluorescence. Theoretically, any structural form that achieves this function is included in the so-called first form, such as a hemispherical or near-hemispherical curing adhesive. During fabrication, liquid optical adhesive is dropped onto the second face 12 and inverted, and the curing time is controlled to form the first form (it can also be fabricated using a nanoimprinting method). For a diamond block containing ensemble NV color centers, it possesses four NV axes, as shown in the attached diagram. Figure 2 As shown.

[0023] The design of the first-form curing adhesive 121 not only improves the optical density of photoluminescence, but also, as we know, the NV color center is located inside the diamond block 1, which means that the photoluminescence is generated inside it and needs to pass through the diamond block-air interface before it can be sensed by the first photoelectric detection module 4. However, the refractive index of the diamond block is much greater than that of air, so the photoluminescence will be reflected by total internal reflection at the interface, which will affect the collection of photoluminescence. In this example, the curing adhesive is used instead of air as the interface in contact with the diamond block 1. Since the refractive index of the curing adhesive is much higher than that of air, this significantly reduces the loss of fluorescence by total internal reflection, so more photoluminescence will pass through the diamond interface, thereby improving the fluorescence collection efficiency. Based on this purpose, in a further design, the refractive index of the first-form curing adhesive 121 is required to be not less than 1.5, preferably around 1.7.

[0024] In this example, the terminal fiber 2 includes a first end 21 and a second end 22. The first end 21 is used to carry external excitation light, preferably a 532nm laser. We know that under the irradiation of this laser, the NV color center will produce red photoluminescence. The second end 22 is configured to input the excitation light from the first surface 11 into the diamond block 1. In this example, the terminal fiber 2 can be a multimode fiber or a single-mode fiber.

[0025] In this example, microwave radiator 3 is used to load external microwave signals and radiate them to diamond block 1; in the attached Figure 1 In the text, the structure of microwave radiator 3 is a planar structure, but in reality, there are many choices for its structure. It can be a spiral copper wire, a microstrip antenna, a coplanar waveguide, etc. Any microwave radiator 3 that can radiate within a specific frequency range can be used.

[0026] In this example, the first photodetector module 4 is located near the second surface 12 and is used to collect the photoluminescence output by the diamond block 1. The specific structure of the first photodetector module 4 is not shown in the diagram, but it has at least a light filter (such as a two-color filter) and a photodetector (such as a photodiode). It can filter out the desired photoluminescence from the mixed light and be detected by the photodetector. Also, it is worth noting that although the first photodetector module 4 mainly collects the photoluminescence output by the second surface 12, if the photoluminescence output by other surfaces of the diamond 12 also propagates towards the first photodetector module 4, it is also within the fluorescence collection range of the first photodetector module 4.

[0027] The solid-state spin sensing structure formed by the above structure is characterized by the use of a curing adhesive with light-gathering function, which can focus the photoluminescence generated by the diamond block. The increase in fluorescence density will significantly improve the measurement bandwidth and response speed in ODMR measurement technology. The bandwidth can improve the measurement accuracy, while the increase in response speed represents the increase in sampling rate. Compared with existing fluorescence focusing lenses, the curing adhesive has lower manufacturing cost and difficulty, is easier to mass-produce, and has a smaller size, making it suitable for small-volume integration with other devices in a confined space.

[0028] In a preferred design, the microwave radiator 3 is selected as a coplanar waveguide (such as an X-type coplanar waveguide). Compared to other microwave radiating structures (such as helical antennas and microstrip antennas), its signal attenuation speed is faster. In existing NV color center sensing designs with light-gathering structures (which are relatively large), it is generally not suitable for use as a microwave radiating device. However, in this invention, the bonding structure between the curing adhesive and the diamond block is extremely small, allowing the coplanar waveguide to be used as a microwave radiator. Based on this, in some more preferred designs, an all-metal structure is selected for the packaging design of the solid-state spin sensing structure. Unlike commonly used microstrip antennas (which are open-field structures, resulting in edge radiation and standing waves generated in the sealed metal cavity, which worsen the return loss), the coplanar waveguide does not have to worry about the metal reflecting microwave signals, and the resulting return loss is negligible. The all-metal packaging design can greatly improve the reliability of the probe design.

[0029] In further design, such as designing the shape of the first-form cured adhesive 121, for example, a hemispherical shape, its function is similar to a hemispherical lens, which can improve the light density of photoluminescence. Based on this, we can optimize the position of the first photodetector module 4 so that it is at the effective light focusing distance of the first-form cured adhesive 121, such as the focal position. We can judge whether the distance between the diamond block 1 and the spherical lens structure 221 is appropriate by the fluorescence intensity sensed by the first photodetector module 4.

[0030] In the aforementioned design of the first-mode cured adhesive 121, the optical focusing function is the main feature. From another perspective, we consider that the cured adhesive formed by some optical adhesives will also produce stray fluorescence under the irradiation of excitation light. The wavelength of this part of the fluorescence is close to that of photoluminescence and cannot be removed by optical filters, thus affecting the purity of photoluminescence. To optimize this problem, in a preferred design, it is required that the formed cured adhesive does not produce photoluminescence under the irradiation of excitation light. Preferably, the cured adhesive material is glass or glass-like material, such as the cured adhesive is a cured product of hydrogenated silicon silsesquioxane photoresist (HSQ photoresist) (similar photoresists include polysiloxane photoresist, organosilane photoresist, polyimide photoresist, or benzocyclobutene photoresist). This kind of cured adhesive will not produce stray fluorescence under the irradiation of excitation light, thus effectively reducing the interference of stray fluorescence.

[0031] Considering that other faces of the diamond block 1 will also emit some photoluminescence outwards, in order to collect this fluorescence, a preferred design also includes several light reflectors 5, which are positioned close to the diamond block 1 to guide some of the light propagating outwards from the non-second face 12 toward the first photodetector module 4. An example scheme is shown in the attached diagram. Figure 3 As shown, there is a light reflector 5 located on the front side of the diamond block 1, with its reflective surface tilted so that the photoluminescence emitted from the front side can be reflected toward the light receiving side of the first photodetector module 4. In other examples, there can be multiple light reflectors 5, with positions corresponding to the rear side, right side, etc. of the diamond block 1, which can change the light path of these originally wasted photoluminescences so that they can be collected. In combination with the curing adhesive design on the second surface 12 mentioned above, in this design, a second-form curing adhesive 122 can also be designed on the surface of the diamond block 1 corresponding to the light reflector 5. Through the high refractive index of the curing adhesive, the total internal reflection loss of the photoluminescence is reduced. At the same time, it is preferred that the second-form curing adhesive 122 is a hemispherical structure, which can focus the photoluminescence.

[0032] Regarding the connection between the terminal optical fiber 2 and the diamond block 1, if the terminal optical fiber 2 does not have a special design, it can generally be directly connected by optical adhesive.

[0033] In another preferred example, we perform a shaping design on the second end 22 of the terminal fiber 2, as shown in the attached figure. Figure 4As shown, it is a spherical lens structure 221. The excitation light transmitted by the terminal optical fiber 2 is focused and output through the spherical lens structure 221, which increases the excitation light density, improves the excitation efficiency of the NV color center, and thus improves the laser fluorescence conversion ratio. The spherical lens structure 221 is formed by cooling the second end 22 after high temperature melting. If we use an optical fiber fusion splicer to discharge and heat the end face of the optical fiber, after the heating is turned off, the molten part of the optical fiber will naturally form a spherical structure under the action of surface tension.

[0034] Considering that the spherical lens structure 221 has an optical focusing effect and a focal point, it is obvious that placing the diamond block 1 at the focal length position will result in a more efficient laser excitation effect. Therefore, in the preferred design, the focal point of the spherical lens structure 221 is located within the spatial position of the diamond block 1. That is, the focal point of the spherical lens structure 221 is controlled to illuminate the inner side of the diamond block 1. Of course, this is only a preferred design; in some cases, the distance between the two can also be controlled according to the probe size requirements. For the aforementioned preferred design, in actual operation, we can judge whether the distance between the diamond block 1 and the spherical lens structure 221 is appropriate by sensing the fluorescence intensity of the first photoelectric detection module 4. Once the distance is determined, they can be bonded together using optical adhesive. Alternatively, the distance can be kept stable through their respective positioning designs, such as positioning and installing them with the microwave radiator 3 using optical adhesive, fiber optic fixing devices, etc., after their positions are determined. To further enhance the positive effect of the spherical lens structure on the excitation light, in a preferred design, as shown in the attached... Figure 5 As shown, at least a portion of the spherical lens structure 221 at the second end 22 has a reflective film 222 coated on the spherical surface near the first end 21. Simulation results show that some excitation light is transmitted from the upper hemisphere of the spherical lens structure 221. By adding a reflective film 222 to this portion, the waste of excitation light can be effectively reduced.

[0035] We know that the polarization direction of the excitation light has a very important influence on the spin excitation efficiency of diamond nitrogen-vacancy centers. For excitation light with a linear polarization direction, the excitation efficiency P of nitrogen-vacancy centers satisfies: P = P 0* [sin 2 (α) + 1 / 9*cos 2 (α)] In the formula, α is the laser polarization angle, and P0 is the total excitation efficiency when the nitrogen-vacancy color center is aligned with the laser polarization direction. It can be observed that when α = 90°, i.e., the laser polarization direction is perpendicular to the axis of the nitrogen-vacancy color center, the excitation efficiency P of the nitrogen-vacancy color center is the highest. However, when φ = 0°, the excitation efficiency P of the nitrogen-vacancy color center is only 1 / 9 of that in the vertical direction, and the laser excitation efficiency reaches its lowest point.

[0036] Based on the aforementioned introduction to the effect of polarization direction on the excitation efficiency of NV color centers, and combined with the design of this scheme, some new improvements can be made. Therefore, in a new preferred design, as shown in the appendix... Figure 6 As shown, a specially made diamond block 1 is used, whose

[111] crystal direction is perpendicular (or approximately perpendicular) to the top surface of the diamond block 1. The terminal fiber 2 is a single-mode polarization-maintaining fiber and is perpendicularly connected to the side of the diamond block 1. In this case, the transmission direction of the linearly polarized excitation light is perpendicular to the

[111] crystal direction, and the polarization direction is also perpendicular to the transmission direction. By adjusting the polarization direction, the polarization direction can be made to be highly perpendicular to the

[111] crystal direction, thereby achieving efficient excitation of the NV color center of the

[111] crystal direction. This design is particularly suitable for the measurement of magnetic fields with a defined direction. When detecting a solid-state spin sensing structure with this design, the magnetic field direction can be made parallel to the

[111] crystal direction. At this time, the NV color center of the crystal direction can fully sense the external magnetic field. Combined with the ODMR measurement method, we can know that in this case, the corresponding peak has a higher bandwidth and contrast. Tracking its resonance frequency without the action of an axial perpendicular magnetic field will improve the measurement accuracy.

[0037] It should be understood that the preferred designs recorded above can be combined in various ways with the initial scheme of Implementation Example 1, provided that the principles do not interfere with each other.

[0038] Example 2 When detecting fluorescence generated by solid-state spin centers, the power of the excitation light illuminating the center is often unstable. Fluctuations in excitation light power cause unnecessary fluctuations in fluorescence intensity, introducing noise into the detection and affecting the accuracy and stability of the results. Therefore, noise reduction of the detected fluorescence is necessary. A common noise reduction method involves splitting the excitation light beam, with one beam applied to the solid-state spin center and the other used as a reference signal. After detection by a detector, differential processing is performed to suppress common-mode noise generated by the excitation light.

[0039] Based on this consideration, and combining the design of Embodiment 1 and its several modified embodiments, Embodiment 2 proposes a solid-state spin sensing structure for noise reduction using differential techniques, as shown in the attached figure. Figure 7 As shown, it also includes a second photoelectric detection module 6 for acquiring reference signals, which is located on the third surface 13 of the diamond block 1. The third surface 13 is the opposite surface of the first surface 11. The second photoelectric detection module 6 is used to acquire the excitation light output through the third surface 13.

[0040] Regarding the selection of the third surface 13, in this example, the third surface 13 is the opposite surface of the first surface 11. It is located on the straight propagation path of the excitation light. The second photoelectric detection module 6 mainly receives the excitation light transmitted from the third surface 13 as a reference signal. Selecting this surface can effectively improve the intensity of the reference signal and improve the noise reduction effect. Of course, this selection is not restrictive. Other surfaces of diamond 1 (generally surfaces other than the first surface 11 and the second surface 12) can also be selected as the third surface.

[0041] Drawing on the aforementioned curing adhesive design, to further enhance the strength of the reference signal, in a preferred example, as shown in the attached figure... Figure 8 As shown, the third surface 13 has a third-form curing adhesive 131, which is used to gather and output light propagating outward from the third surface 13. The third-form curing adhesive 131 has a similar function to the first-form curing adhesive 121, so the form requirements are similar, such as a hemispherical lens-shaped curing adhesive design. Alternatively, a special curing adhesive (such as a cured HSQ photoresist) can be selected so that it does not produce stray light under the irradiation of excitation light.

[0042] Example 3

[0043] Another aspect of this application also describes a quantum magnetometer for measuring the magnetic field strength and direction of a magnetic field to be measured, having at least one solid-state spin sensing structure as described above. An exemplary scheme is shown in the appendix. Figure 9 As shown, the quantum magnetometer is equipped with a laser unit, a microwave unit, and a data processing unit. The laser unit provides the required excitation light to the solid-state spin sensing structure, the microwave unit provides the required microwave signal to the solid-state spin sensing structure, and the solid-state spin sensing structure transmits the photocurrent signal (the electrical signal converted from photofluorescence, or the electrical signal converted from photofluorescence and the reference signal) to the data processing unit for processing and calculation.

[0044] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0045] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to any specific implementation. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A solid-state spin sensing structure based on a curable adhesive, characterized in that, include: - A diamond block containing an ensemble NV color center, comprising a first facet and a second facet, wherein the second facet is provided with a first-form cured adhesive for gathering and outputting light propagating outward from the second facet; - A terminal optical fiber, comprising a first end and a second end, the first end being used to load external excitation light, and the second end being configured to input the excitation light from the first surface into the diamond block; - A microwave radiator, used to load external microwave signals and radiate them onto the diamond block; - A first photoelectric detection module, located near the second surface, is used to collect the photoluminescence output by the diamond block.

2. The solid-state spin sensing structure according to claim 1, characterized in that, The microwave radiator is a coplanar waveguide.

3. The solid-state spin sensing structure according to claim 1, characterized in that, It also has several light reflectors, which are positioned close to the diamond block, to guide some of the light propagating outward from the non-second surface toward the first photoelectric detection module.

4. The solid-state spin sensing structure according to claim 3, characterized in that, The surface of the diamond block facing the light reflector has a second type of cured adhesive.

5. The solid-state spin sensing structure according to claim 1, characterized in that, It also includes a second photoelectric detection module for acquiring reference signals, which is located on the third face of the diamond block, the third face being the opposite face of the first face. The second photoelectric detection module is used to acquire the excitation light output through the third face.

6. The solid-state spin sensing structure according to claim 5, characterized in that, The third surface has a third-shaped cured adhesive, which is used to gather and output light that propagates outward from the third surface.

7. The solid-state spin sensing structure according to any one of claims 1-6, characterized in that, The refractive index of the cured adhesive is not less than 1.

5.

8. The solid-state spin sensing structure according to any one of claims 1-6, characterized in that, The cured adhesive does not produce photoluminescence under excitation light.

9. The solid-state spin sensing structure according to claim 8, characterized in that, The curing adhesive is a cured product of hydrogenated silicon silsesquioxane photoresist, polysiloxane photoresist, organosilane photoresist, polyimide photoresist, or benzocyclobutene photoresist.

10. A quantum magnetometer for measuring the magnetic field strength and direction of a magnetic field to be measured, characterized in that, It has at least one solid-state spin sensing structure as described in any one of claims 1-9.

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