Solid-state spin defect-based probe, sensing structure, system, and method

Abstract

The present application provides a solid-state spin defect-based probe, a sensing structure, a system, and a method. The probe comprises an optical waveguide, which has a light input end and a light output end and is provided with at least one light leakage region on a portion between the light input end and the light output end, wherein each light leakage region is configured to leak part of light transmitted in the optical waveguide, and the light output end and / or each light leakage region of the optical waveguide are / is used as a light excitation port. The probe further comprises at least one sensitive body arranged in one-to-one correspondence on at least one light excitation port, wherein each sensitive body has a solid-state spin defect. In the present application, light beam splitting is implemented and a light beam splitting structure is greatly simplified; by means of the photoluminescence effect of the solid-state spin defect, multi-point detection can be implemented at a plurality of light excitation ports; during detection of excitation light at the light excitation ports, the input power of the excitation light can be regulated on the basis of a detected signal, thereby improving the stability of the excitation light; and noise reduction can be realized by means of differential processing, thereby improving the detection accuracy.

Description

A probe, sensing structure, system, and method based on solid-state spin color centers.

[0001] This application claims priority to Chinese Patent Application No. 202411173124.X, filed on August 26, 2024, entitled "A Probe, Sensing Structure, System and Method Based on a Solid-State Spin Center", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of quantum sensing, and in particular to a probe, sensing structure, system and method based on a solid-state spin color center. Background Technology

[0003] Quantum-based precision measurement techniques, such as utilizing the interaction between solid-state spin centers and their surrounding environment, and then reading out the intensity of this interaction through optical means to achieve high-precision measurements, have been widely applied in the measurement of magnetic fields, temperature, electric fields, and stress. For specific solid-state spin centers such as diamond NV centers, silicon carbide centers, and hexagonal boron nitride centers, measurements are achieved based on the photoluminescence of the solid-state spin centers and the manipulation of electron spin by external magnetic fields and microwave fields.

[0004] The power of excitation light illuminating a solid-state spin center is often unstable, causing unnecessary fluctuations in the fluorescence intensity generated by the solid-state spin center, introducing noise into the detection and affecting the accuracy and stability of the detection results. Existing technologies use beam splitters or fiber optic beam splitters to divide the excitation light into two beams: one beam is used for stability control of the excitation light and to reduce noise caused by power instability; the other beam is used for excitation of the spin center. Beam splitters and beam splitters are relatively large, making them unsuitable for miniaturized, highly integrated sensors. When using beam splitters, to prevent interference between the split beams, a longer transmission distance is required for spatial light transmission, increasing the space occupied by the optical path. Even with fiber optic transmission, a fixed structure is needed at the beam splitter to facilitate light coupling into the fiber, further increasing the size and flexibility of the optical path structure. While fiber optic beam splitters are relatively flexible, they still occupy a large space and require guiding the light into the splitting fiber for separation. The propagation of light within the splitting fiber increases noise and degrades stability. Therefore, how to simplify the optical beam splitting structure in quantum detection has become a technical problem that needs to be solved.

[0005] Summary of the Invention

[0006] In view of the shortcomings of the prior art described above, the purpose of this application is to provide a probe, sensing structure, system and method based on solid-state spin color centers to solve the problem that the optical beam splitting structure occupies a large space and is not conducive to application in miniaturized sensors.

[0007] To achieve the above and other related objectives, this application provides a probe based on a solid-state spin color center, comprising: an optical waveguide having an optical input end and an optical output end, and at least one light leakage region disposed on the portion located between the optical input end and the optical output end, each light leakage region being used to leak out a portion of the light transmitted in the optical waveguide, the optical output end of the optical waveguide and each light leakage region serving as an optical excitation port; and at least one sensor disposed correspondingly on at least one optical excitation port therein, each sensor containing a solid-state spin color center.

[0008] In an exemplary embodiment, the light leakage region is formed by changing the shape of the core layer and cladding interface, or by exposing at least a portion of the cladding cross-section to the outside, or by exposing the outer surface of the core layer to the outside, or by exposing at least a portion of the core layer cross-section to the outside.

[0009] In one exemplary embodiment, a focusing structure is provided at the at least one photoexcitation port for focusing the light emitted from the photoexcitation port or the light generated by the sensor.

[0010] In one exemplary embodiment, the light leakage region is filled with a filler having a set refractive index.

[0011] In one exemplary embodiment, the refractive index of the filler changes with temperature, and a temperature control device is provided for regulating the temperature of the filler.

[0012] In an exemplary embodiment, the solid-state spin color center is one of the following: diamond nitrogen-vacancy color center, diamond germanium-vacancy color center, diamond silicon-vacancy color center, silicon carbide double-vacancy color center, silicon carbide silicon-vacancy color center, and hexagonal boron nitride boron-vacancy color center.

[0013] To achieve the above and other related objectives, this application also provides a sensing structure based on a solid-state spin center, comprising: a probe based on a solid-state spin center as described in any of the preceding claims, wherein the optical input end of the optical waveguide is used to input excitation light, and the excitation light is used to excite the solid-state spin center to generate fluorescence;

[0014] The photoelectric detection module includes at least one first photodetector facing the sensitive object and corresponding to at least one sensitive object, each first photodetector being used to detect the fluorescence generated by the corresponding sensitive object and output a fluorescence electrical signal;

[0015] The filtering module includes a first filter located between each sensor and a corresponding first photodetector for filtering out fluorescence.

[0016] In an exemplary embodiment, the photoelectric detection module further includes at least one second photodetector facing at least one light excitation port and corresponding one-to-one with the at least one light excitation port. Each second photodetector is used to detect the excitation light emitted from the corresponding light excitation port and output an excitation photoelectric signal.

[0017] In one exemplary embodiment, the filtering module further includes a second filter located between each second photodetector and the corresponding photoexcitation port for filtering out the excitation light.

[0018] In an exemplary embodiment, a light adjustment element is further provided between each second photodetector and the corresponding light excitation port to adjust the intensity of the excitation light entering the corresponding second photodetector.

[0019] In one exemplary embodiment, the system further includes a microwave radiation module, wherein at least a portion of the sensors are located within the radiation zone of the microwave radiation module.

[0020] To achieve the above and other related objectives, this application also provides a sensing system based on a solid-state spin color center, comprising: an excitation source and a sensing structure based on a solid-state spin color center as described in any of the preceding claims; the excitation source is connected to the optical input end of an optical waveguide for inputting excitation light.

[0021] In an exemplary embodiment, the system further includes an analog circuit module and a control module connected to each other. The analog circuit module is also connected to the excitation light source and the photodetector module. When the photodetector module collects the excitation light from the excitation port and acquires the excitation photoelectric signal, the analog circuit module processes the excitation photoelectric signal from the photodetector module and transmits it to the control module. The control module is used to transmit a control signal to the analog circuit module according to the excitation photoelectric signal. The analog circuit module controls the driving of the excitation light source according to the control signal.

[0022] In one exemplary embodiment, the analog circuit module further performs differential processing on each of the at least one fluorescent electrical signal transmitted by the photodetector module and one excitation photoelectric signal.

[0023] In an exemplary embodiment, when a microwave radiation module is present and at least one sensitive object is not irradiated with microwaves, the fluorescence electrical signal of the irradiated sensitive object detected by the photoelectric detection module is used as a measurement electrical signal, and the fluorescence electrical signal of the unirradiated sensitive object is used as a reference electrical signal. The analog circuit module further performs differential processing on each of the at least one measurement electrical signal transmitted by the photoelectric detection module and one reference electrical signal.

[0024] In an exemplary embodiment, when a microwave radiation module is present, a microwave generation module is further included for generating microwaves and transmitting microwaves to the microwave radiation module. The module also includes a lock-in amplifier and a data processing module connected to each other. The lock-in amplifier is also connected to the microwave generation module and the analog circuit module for transmitting microwave modulation signals to the microwave generation module and demodulating fluorescent electrical signals or differential signals transmitted to it by the analog circuit module. The data processing module is used to receive the demodulated signals from the lock-in amplifier.

[0025] To achieve the above and other related objectives, this application also provides a detection method based on solid-state spin centers, comprising:

[0026] At least one light leakage region is provided between the optical input end and the optical output end of an optical waveguide, and each light leakage region is used to leak out a portion of the light transmitted in the optical waveguide; the optical output end of the optical waveguide and each light leakage region are used as optical excitation ports, and a sensor is provided on at least one of the optical excitation ports in a one-to-one correspondence, each sensor containing a solid-state spin color center.

[0027] Place the sensitive object that needs to be tested in the test environment;

[0028] An excitation light is input to the light input terminal, and the excitation light is used to excite the solid spin center to produce fluorescence.

[0029] Perform detection using any of the following methods:

[0030] Method 1: Detect the fluorescence generated by at least one sensitive object to obtain a fluorescence electrical signal, and obtain the quantifier within the measurement range of the corresponding sensitive object based on the fluorescence electrical signal; or detect the fluorescence generated by at least one sensitive object to obtain a fluorescence electrical signal, and for each sensitive object, irradiate it with microwaves, obtain the fluorescence electrical signal at each frequency by scanning the microwave frequency, then plot ODMR (Optically Detected Magnetic Resonance) spectral lines based on the fluorescence electrical signals, and obtain the quantifier within the measurement range of the corresponding sensitive object based on the ODMR spectral lines.

[0031] Method 2: Detect the excitation light emitted from one of the photoexcitation ports to obtain the excitation photoelectric signal, and detect the fluorescence generated by at least one sensor to obtain the fluorescence electrical signal. For each sensor, the detected fluorescence electrical signal and the excitation photoelectric signal are differentially processed to obtain a differential signal. The measurand within the measurement range of the corresponding sensor is obtained based on the differential signal. Alternatively, detect the excitation light emitted from one of the photoexcitation ports to obtain the excitation photoelectric signal, and detect the fluorescence generated by at least one sensor to obtain the fluorescence electrical signal. For each sensor, microwaves are also irradiated onto it. By scanning the microwave frequency, the fluorescence electrical signal at each frequency is obtained. The differential signal between the fluorescence electrical signal and the excitation photoelectric signal at each frequency is calculated. Then, ODMR spectra are plotted based on the differential signals, and the measurand within the measurement range of the corresponding sensor is obtained based on the ODMR spectra.

[0032] Method 3: In the same environment, detect the fluorescence generated by at least one sensitive object to obtain a fluorescence electrical signal. Irradiate microwaves to at least one of the sensitive objects and scan the microwave frequency. Use the detected fluorescence electrical signal as the measurement electrical signal. Do not irradiate microwaves to the remaining sensitive object and use the detected fluorescence electrical signal as the reference electrical signal. For each sensitive object irradiated with microwaves, perform differential processing between its measurement electrical signal and the reference electrical signal to obtain the differential signal at each frequency. Then, plot the ODMR spectrum based on the differential signal and obtain the quantifier within the measurement range of the corresponding irradiated sensitive object based on the ODMR spectrum.

[0033] In an exemplary embodiment, in either mode one or mode three, excitation light emitted from one of the optical excitation ports is also detected to obtain an excitation photoelectric signal. For any of the three modes, the power of the excitation light input to the optical input terminal is also adjusted according to the excitation photoelectric signal.

[0034] As described above, the probe, sensing structure, system, and method based on solid-state spin centers of this application have the following beneficial effects:

[0035] 1. By setting at least one light leakage region between the optical input end and the optical output end of the optical waveguide, a portion of the light transmitted in the optical waveguide leaks out through each light leakage region. The optical output end of the optical waveguide and each light leakage region are used as optical excitation ports. A sensor containing a solid-state spin center is set at at least one optical excitation port. Thus, the light beam is split in the designed probe through the light leakage region of the optical waveguide, which greatly simplifies the optical beam splitting structure. Moreover, the size of the optical waveguide is small, generally in the micrometer range. The size and position of the light leakage region can be flexibly adjusted as needed, which can be applied to miniaturized and highly integrated sensors.

[0036] 2. Fill the light leakage area with a filler having a set refractive index or an adjustable refractive index, and then adjust the collection efficiency or emission ratio of the leaked light by changing the light refractive index, so as to achieve flexible control of the light intensity.

[0037] 3. By inputting excitation light into the optical waveguide, the photoluminescence effect of the solid-state spin center can be used to detect magnetic fields, temperature, etc. Firstly, multi-point detection can be achieved through multiple optical excitation ports. Secondly, by detecting the excitation light at the optical excitation port, the input power of the excitation light can be adjusted according to the detected signal, thereby improving the stability of the excitation light. Thirdly, the detection of magnetic fields, temperature, etc. can be achieved by differential processing of fluorescence and excitation light, or by using a sensor irradiated by microwaves and a sensor not irradiated by microwaves. Differential processing can reduce noise and improve detection accuracy. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0039] Figure 1 shows a schematic diagram of the first structure of the probe of this application;

[0040] Figure 2 shows a schematic diagram of the second structure of the probe in this application;

[0041] Figure 3 shows a schematic diagram of the third structure of the probe in this application;

[0042] Figure 4 shows a schematic diagram of the structure of the closed cavity in this application;

[0043] Figure 5 shows a schematic diagram of the fourth structure of the probe in this application;

[0044] Figure 6 shows a schematic diagram of the fifth structure of the probe of this application;

[0045] Figure 7 shows a schematic diagram of the first structure of the sensing structure of this application;

[0046] Figure 8 shows a schematic diagram of the second structure of the sensing structure of this application;

[0047] Figure 9 shows a schematic diagram of the third structure of the sensing structure of this application;

[0048] Figure 10 shows a schematic diagram of the sensing system of this application.

[0049] Reference numerals: 1—Optical waveguide; 11—Optical input end; 12—Optical output end; 13—Light leakage area; 131—Filling material; 14—Focusing structure; 15—Enclosed cavity; 151—Sealed area; 152—Filling hole; 16—Temperature control unit; 17—Core layer; 18—Cladding layer; 19—Coating layer; 2—Sensitive element; 3—First photodetector; 4—First filter; 5—Microwave antenna; 6—Second photodetector; 7—Optical adjustment component; 8—Second filter; 10—Excitation source; 20—Analog circuit module; 30—Control module; 40—Microwave generation module; 50—Lock-in amplifier; 60—Data processing module. Detailed Implementation

[0050] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. This application can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that, unless otherwise specified, the following embodiments and features in the embodiments can be combined with each other.

[0051] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of this application. Therefore, the illustrations only show the components related to this application and are not drawn according to the number, shape and size of the components in actual implementation. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0052] Example 1: As shown in Figure 1, this example provides a probe based on a solid-state spin color center, including: an optical waveguide 1 having an optical input end 11 and an optical output end 12, and at least one light leakage region 13 is provided on the portion located between the optical input end 11 and the optical output end 12, each light leakage region 13 being used to leak out a portion of the light transmitted in the optical waveguide 1, and the optical output end 12 of the optical waveguide 1 and each light leakage region 13 serving as a light excitation port; it also includes at least one sensor 2 correspondingly disposed on at least one light excitation port therein, each sensor 2 containing a solid-state spin color center.

[0053] Figure 1 provides an example of a light leakage region 13. Figure 2 shows the case of multiple light leakage regions 13. The structures of the light leakage regions 13 can be the same or different, and they are arranged along the axis of the optical waveguide 1.

[0054] As exemplarily shown in Figure 1, the sensor 2 is disposed on the light output end 12 of the optical waveguide 1. The sensor 2 can be connected to the end face of the light output end 12 by adhesive bonding, receiving excitation light input from the light input end 11 and output from the light output end 12, and thus generating fluorescence under the excitation of the excitation light. The end face of the light output end 12 can be configured as a plane, an arc-shaped convex surface, or a conical surface.

[0055] Therefore, by setting the light leakage region 13, the light is split into beams, and the light output end 12 and at least one light leakage region 13 serve as the light excitation port for output. In this embodiment, only the optical waveguide 1 is used to achieve beam splitting, which greatly simplifies the optical beam splitting structure. Moreover, the size of the optical waveguide 1 is small, generally in the micrometer range. The size and position of the light leakage region 13 can be flexibly adjusted as needed, enabling its application in integrated and miniaturized sensors.

[0056] For a typical optical waveguide, it consists of a core layer 17 and a cladding layer 18 from the inside out. The outer surface of the core layer 17 can be completely covered by the cladding layer 18, such as in columnar optical fibers or embedded strip waveguides. It can also have a stacked structure, such as a planar waveguide with a core layer 17 in the middle and cladding layers 18 on the top and bottom, or a strip waveguide with the core layer 17 embedded within or located on the surface of the cladding layer 18. Optical fibers can be divided into bare fibers and fibers with protective layers. For bare fibers, a coating layer 19 is provided outside the cladding layer 18. For fibers with protective layers, a protective layer covers the outside of the cladding layer 18. Figure 1 illustrates an example of a bare fiber including a coating layer 19. Regardless of the type of optical waveguide, the principle of light transmission in the waveguide is the same: light propagates in the core layer 17 and undergoes total internal reflection at the interface between the core layer 17 and the cladding layer 18, preventing light propagating in the core layer 17 from leaking out. In this embodiment, a light leakage region 13 is provided in the portion between the optical input end 11 and the optical output end 12, allowing a portion of the light propagating in the optical waveguide to leak out, thereby achieving light beam splitting. The optical fiber in this embodiment can be a single-mode fiber or a dual-mode fiber.

[0057] In this embodiment, a section of the optical waveguide 1 is processed to change the shape of the interface between the core layer 17 and the cladding layer 18 in the waveguide section where the light leakage region 13 is located. This changes the incident angle of light at the interface between the core layer 17 and the cladding layer 18 in this section, thereby altering the total internal reflection condition and allowing light to leak out from the cladding layer 18. For example, for an optical fiber, the area to be processed can be heated and stretched to change the incident angle of light at the interface between the core layer 17 and the cladding layer 18, thereby altering the total internal reflection condition and allowing some light in the core layer 17 to leak out. As shown in Figure 1, after stretching, the light leakage region 13 is hourglass-shaped. Figure 1 exemplarily shows the removal of the outer layer of the area to be processed, such as the coating layer 19 or the protective layer. The removal method can be scraping, peeling, polishing, or heating removal, followed by stretching, which can achieve a better light leakage effect. Different light leakage intensities can be obtained by selecting different stretching lengths. For other types of optical waveguides, the shape of the interface between the core layer 17 and the cladding layer 18 of the waveguide segment where the light leakage region 13 is located can be changed during the optical waveguide forming stage. For example, the interface between the cladding layer 18 and the core layer 17 of the light leakage region 13 can be made into an hourglass shape or a cone shape as shown in Figure 9.

[0058] Alternatively, after the cladding 18 is exposed to the outside, at least part of the cladding 18 can be removed so that some of the light entering the cladding 18 can leak out. This method may result in less leaked light and is more suitable for situations where the required light intensity is weak.

[0059] In this embodiment, the setting of the light leakage region 13 not only simplifies the beam splitting structure, but also allows the light propagating in the optical waveguide 1 to be directly separated from the light leakage region 13, without the need to introduce the beam splitting fiber for separation as in an optical fiber beam splitter, which can effectively reduce noise and improve stability.

[0060] To increase the collection of light leakage in the light leakage region 13 and minimize its size, for example, in this embodiment, an optical fiber is stretched to allow light to leak out and obtain the required leakage light intensity. This places certain requirements on the stretching length of the optical fiber; a large stretching length is required for the required light intensity, but since the optical fiber is relatively thin, excessive stretching can easily lead to breakage. Therefore, as shown in Figure 2, a filler 131 is filled in the light leakage region 13. The filler 131 has a set refractive index to change the original refractive index, increase the collection efficiency of the leaked light, or increase the light emission ratio. Furthermore, by adjusting the size of the filler 131, the size and light leakage efficiency of the light leakage region 13 can be flexibly controlled. The filling material 131 functions similarly to an optical lens. Different refractive indices of the filling material 131 result in different light collection effects or light emission ratios. Fillers with higher refractive indices can be selected, such as optical adhesives like UV-curable adhesives, or PDMS (polydimethylsiloxane). Liquids such as water and glycerin can also be used. For liquid filling materials, a closed cavity 15, as shown in Figure 3, can be used to seal the light leakage area 13. The shape of the filling material 131 is configured to converge light, for example, by setting it as a lens structure with a convex surface.

[0061] Figure 2 illustrates that the sensor 2 is also fixed to the light leakage area 13 by a solid filler such as optical adhesive or PDMS. On the one hand, the sensor 2 can be fixed, and on the other hand, the optical adhesive or PDMS used for fixing fills the light leakage area 13, which can improve the collection efficiency of the leaked light and improve the excitation efficiency of the solid spin center.

[0062] The solid-state spin color center is one of the following: diamond nitrogen-vacancy color center, diamond germanium-vacancy color center, diamond silicon-vacancy color center, silicon carbide double-vacancy color center, silicon carbide silicon-vacancy color center, or hexagonal boron nitride boron-vacancy color center. The sensing element 2 is an aggregate of bulk, granular, or powdered structures. In this embodiment, the sensing element 2 is exemplarily a diamond containing nitrogen-vacancy color centers, with dimensions in the nanometer or micrometer range.

[0063] The wavelength of the excitation light may differ for different solid-state spin centers. For example, 532nm green excitation light is generally used for diamond nitrogen-vacancy centers and hexagonal boron nitride boron-vacancy centers; 900-940nm excitation light is used for silicon carbide double-vacancy centers; and other centers can be excited by the corresponding excitation light, which will not be elaborated here.

[0064] In this embodiment, the size of the optical waveguide 1 used in the probe can be adjusted as needed. To meet the requirements of high integration, it can be made to the millimeter level or even smaller, and can be applied to miniaturized and highly integrated sensors.

[0065] Example 2: In this example, a section of the optical waveguide 1 is processed to expose the outer surface of the core layer 17 to the outside. For example, for optical fibers, this can be done by scraping, stripping, or polishing; for other types of waveguides, the cladding 18 is removed during the forming stage using etching or other processes. As shown in Figure 2, after removing the cladding 18, some light in the core layer 17 is refracted to form a light leakage region 13. In this example, as shown in Figure 3, the core layer 17 can also be further partially removed to expose at least a portion of its cross-section to the outside.

[0066] In this embodiment, a light-concentrating structure 14 is provided at at least one light excitation port to concentrate the light emitted from the light excitation port or the light generated by the sensor 2.

[0067] The focusing structure 14 can be a focusing lens, and the light excitation port can be at least partially located inside the focusing lens. The focusing lens can be a TIR lens (i.e., a total internal reflection lens) as shown in Figures 2, 4, 8, and 9. The incident surface of the TIR lens is a groove recessed into the lens body (as shown by the dashed line in Figure 4). The light excitation port can be at least partially located in the groove of the TIR lens (as shown in Figures 2 and 9) or inside the lens body. Specifically, holes or slots can be drilled in the side wall of the groove or in the lens body (only the hole or slot structure inside the TIR lens is shown in the figure), and the optical waveguide 1 can be inserted or inserted, so that the light excitation port is partially or completely located inside the groove or inside the lens body; or the groove of the TIR lens can be directly aligned with the filler 131 of the light leakage area 13, and the filler 131 can be built into the groove of the lens; or the light excitation port can be housed in the lens body and integrated with the focusing lens. The TIR lens performs total internal reflection to focus the light, which then exits from the other end face, thus collecting the light beam or obtaining light of the desired intensity. Other lenses can also be used, such as the hemispherical lens shown in Figure 7, the compound parabolic condenser shown in Figure 3 or Figure 10, and aspherical lenses, all of which can achieve light focusing. Slots or perforations can be made in these lenses to place the light excitation port inside the condenser lens, or the light excitation port can be housed inside the condenser lens, forming an integral structure with the condenser lens.

[0068] The sensor 2 can also be located inside the condenser lens together with the light excitation port, as shown in Figures 2, 7, and 10; or it can be located outside the condenser lens, for example, at the light emitting end of the condenser lens, to receive the excitation light focused by the condenser lens. Of course, the light excitation port can also be located outside the condenser lens, as exemplified in Figure 8, where light is refracted into the condenser lens for focusing. The sensor 2 can be located outside the condenser lens, for example, between the light excitation port and the incident surface of the condenser lens or at the light emitting end of the condenser lens. The sensor 2 can also be located alone inside the condenser lens.

[0069] The focusing structure 14 can also be a cavity structure with an opening, as shown in Figure 5, with the light excitation port located inside the cavity structure. The cavity can be made of metal, with the inner wall reflecting light and emitting it through the opening to achieve light focusing; the cavity can also be made of non-metallic material, with the inner wall covered by a light-reflecting film to reflect light and emit it through the opening. The light-reflecting film can be a metal film or a non-metallic high-reflectivity film, such as titanium dioxide, zinc oxide, or other metal oxide materials. The sensor 2 can be located inside the cavity as shown in Figure 5, or it can be located outside the cavity and facing the opening.

[0070] To enhance the adjustability of the leaked light intensity, the filler 131 filling the light leakage region 13 is selected from substances whose refractive index changes with temperature, such as water, glycerin, ethanol, methanol, liquid paraffin, vegetable oil (e.g., linseed oil), PDMS (polydimethylsiloxane), optical adhesive, etc., as shown in Figures 3 and 4. For liquid fillers, a closed cavity 15 can be used to seal the light leakage region 13. A temperature control device 16, such as a semiconductor cooling chip, a non-metallic heating element, or a thermally conductive metal material, is set inside or outside the closed cavity 15 to regulate the temperature of the filler, thereby obtaining the required light output and maintaining the stability of the light output. In Figure 3, the temperature control device 16 is set outside the closed cavity 15 and located on the side of the optical waveguide 1 opposite to the light leakage region 13. By adjusting the temperature of the temperature control device 16, the refractive index of the filling liquid changes, thereby adjusting the light output ratio of the light leakage region 13 to achieve the adjustment of the leaked light intensity. For solid fillers, the sealing cavity 15 can be selectively added or not added. For example, cured PDMS can be filled in the light leakage area 13 by filling the light leakage area 13 with PDMS solution and curing it at high temperature, so that it is filled in the light leakage area 13 in solid form.

[0071] In this embodiment, the sealed cavity 15 can be made of a light-transmitting material, such as glass or other materials with low self-fluorescence and high light transmittance. After the optical waveguide 1 is inserted into the cavity, it is sealed by sealing the gaps at both ends of the sealed cavity 15, as shown in the sealing area 151 in Figures 3 and 4. The filling liquid is injected into the light leakage area 13 located in the middle of the cavity through the sealing area 151 by an extremely fine injection needle. The sealed cavity 15 after filling with liquid can be sealed again to improve the sealing performance.

[0072] Alternatively, as shown in Figure 4, a filling hole 152 can be formed on the wall of the sealed cavity 15 near the light leakage area 13. After sealing the sealed cavity 15, the filling liquid is injected into the light leakage area 13 inside the cavity through the filling hole 152. After filling, the filling hole 152 can be sealed with adhesive. Figure 4 also shows an example of setting a temperature control device 16 in the sealed cavity 15, which facilitates placing the entire sealed cavity 15 into the condenser lens. The temperature control device 16 can adopt the aforementioned structure, or it can be a small heat-conducting wire or heat-conducting strip, and be connected to an external cooling or heat dissipation device. Alternatively, a semiconductor temperature control layer can be directly deposited on the inner wall of the sealed cavity and connected to an external cooling or heat dissipation device. A partition can also be set between the temperature control device 16 and the optical waveguide 1 to prevent the filling liquid from seeping into the temperature control device 16.

[0073] When the sensor 2 is located in the light leakage region 13, and the light leakage region 13 is filled with filler 131, and the temperature of the filler 131 is adjusted, the sensor 2 and the filler 131 need to maintain a certain distance. For example, the sensor 2 and the light leakage region 13 can be placed inside the light-concentrating structure 14 and outside the light-concentrating structure 14, so as to reduce the influence of temperature on the photoluminescence of the solid spin color center. As shown in FIG4, the sensor 2 is located inside the light-concentrating structure 14 and the light leakage region 13 is located outside the light-concentrating structure 14.

[0074] Example 3: In this example, the optical waveguide 1 is truncated or misaligned to expose at least a portion of the core layer 17 to the outside, thereby forming a light leakage region 13. Figures 5 and 6 show the partial exposure of the core layer 17 of the optical waveguide 1. Figure 5 shows a partial truncation method, while Figure 6 shows a misaligned connection between the ends of the two optical waveguides 1. The connection method can be direct contact or fusion welding. Figure 8 shows the entire core layer 17 exposed to the outside.

[0075] The light leakage area 13 in this embodiment can also be treated with the filler 131 as in Embodiment 1 or Embodiment 2, which will not be described again here.

[0076] Figure 6 is a top view from the condenser lens side. Through misalignment, part of the cross-section of the core layer 17 is aligned with part of the cross-section of the cladding layer 18, so that some of the light in the core layer 17 enters the cladding layer 18 and then leaks out.

[0077] In Figure 8, the sensitive body 2 can also be placed at the light leakage area 13, and located between the broken sections.

[0078] Example 4: This example provides a sensing structure based on a solid-state spin color center, as shown in Figures 7-9. It includes a probe, a photodetector module, and a filter module as described in any of Examples 1 to 3. The photodetector module includes at least one first photodetector 3 facing the sensor 2 and corresponding to at least one sensor 2. Each first photodetector 3 is used to detect the fluorescence generated by the corresponding sensor 2 and output a fluorescence electrical signal. The filter module includes a first filter 4 located between each sensor 2 and the corresponding first photodetector 3 for filtering out fluorescence.

[0079] As shown in Figure 7, two sensors 2 are provided, located at the light output end 12 and a light leakage region 13, respectively. Thus, the fluorescence signal of each sensor 2 can be obtained through the photoluminescence effect of the solid-state spin center, enabling multi-point detection, such as multi-point magnetic field detection. Alternatively, as shown in Figure 2, multiple light leakage regions 13 can be provided, with a sensor 2 placed in each light leakage region 13, to achieve multi-point measurement.

[0080] Alternatively, a microwave radiation module can be set up to radiate microwaves onto at least a portion of the sensitive objects 2. For each sensitive object 2 irradiated with microwaves, the fluorescence signal at each frequency is acquired by scanning the microwaves. Then, ODMR spectra are plotted based on the fluorescence signals, and the measurands to be measured, such as magnetic fields and temperatures, are obtained from the ODMR spectra within the measurement range of the corresponding sensitive object 2. The measurement range for each sensitive object 2 includes at least the measurement range of its occupied volume. For uniform measurement environments, such as uniform magnetic fields or temperatures, this can be extended to the range of larger uniform locations.

[0081] Microwaves can be selectively irradiated onto at least one sensitive object 2, and the microwave frequency can be scanned. The detected fluorescence signal is used as the measurement signal. For the remaining sensitive object 2, no microwaves are irradiated, and the detected fluorescence signal is used as the reference signal. For each irradiated sensitive object 2, the measured signal and the reference signal are differentially processed to obtain the differential signal at each frequency. ODMR spectra are plotted based on the differential signals, and the measurand within the measurement range of the irradiated sensitive object 2 can be obtained from the ODMR spectra. For example, for multi-point detection, after obtaining the magnetic field or temperature at each point, the magnetic field distribution or temperature distribution can be obtained. Therefore, by using irradiated and unirradiated sensitive objects 2 for fluorescence differential processing, noise from the excitation source 10, as well as background noise in the generated fluorescence and the environment, can be reduced, improving the accuracy and stability of the measurement. Furthermore, the reduction in noise also helps to improve the sensitivity of resonance peak identification in ODMR detection.

[0082] The photoelectric detection module further includes at least one second photodetector 6 facing at least one light excitation port and corresponding one-to-one with the at least one light excitation port. Each second photodetector 6 is used to detect the excitation light emitted from the corresponding light excitation port and output an excitation photoelectric signal. As exemplified in FIG8, the excitation light is detected in one of the light leakage regions 13.

[0083] Each filter can correspond to one or more photodetectors. The figure exemplifies a one-to-one correspondence. For multiple adjacent sensors 2, one filter can be used. The microwave radiation module can consist of one or more microwave antennas 5. Multiple sensors 2 can be located within the radiation area of ​​one microwave antenna 5, or they can correspond one-to-one with the radiation areas of multiple microwave antennas 5. The microwave antennas 5 can be coplanar waveguide antennas as shown in Figures 7-9, helical antennas as shown in Figure 10, or other types of antennas.

[0084] The photoelectric detection module, the filter module, and the focusing structure 14 can be spaced apart as shown in Figure 9, or they can be fitted together as shown in Figures 7, 8, and 10.

[0085] The power of the excitation light input to the light input terminal 11 can be adjusted according to the detected excitation photoelectric signal so that the excitation light is in a stable state or the power required for emission.

[0086] Alternatively, the fluorescence electrical signal and the excitation photoelectric signal from each sensor 2 can be differentially processed, and the differential signal can be used to perform the calculation of the measurement to achieve noise reduction.

[0087] Alternatively, as shown in Figure 10, by setting up a microwave-irradiated sensor 2 and a non-microwave-irradiated sensor 2, the fluorescence electrical signals of the two are differentially processed to achieve noise reduction; at the same time, the excitation light emitted from a light excitation port is detected, and the power of the excitation light input to the light input terminal 11 is controlled by using the excitation photoelectric signal.

[0088] During differential noise reduction, to better reduce common-mode noise, the excitation photoelectric signal and the fluorescence electrical signal are made consistent during initial detection. For example, when using a photodetector, the current values ​​detected by the two detectors are the same, i.e., the difference is zero. However, in the two detected light paths, the fluorescence intensity is generally weaker than the excitation light intensity, requiring adjustment of the excitation light's intensity to control its detection requirements. To achieve this adjustment, the method of filling the light leakage region 13 with filler 131, as described in Embodiment 1 or Embodiment 2, can be used. Alternatively, as shown in Figures 9-10, a light adjustment element 7 can be provided between the light excitation port and the second photodetector 6. The light adjustment element 7 is configured to adjust the light transmission intensity. It can be a light transmission area with an adjustable area, where the light transmission area is adjusted to control the light quantity, such as an aperture; or it can reduce the light transmission intensity by absorbing, scattering, or reflecting light, such as an attenuator. Furthermore, when setting the focusing structure 14, the light adjustment element 7 can be placed between the focusing structure 14 and the second photodetector 6 as shown in Figures 9 and 10; alternatively, when using a focusing lens to focus light, the light adjustment element 7 can be placed between the light excitation port and the focusing lens.

[0089] When the photoexcitation port for detecting the excitation light is close to the sensor 2, in order to reduce the interference of fluorescence on the detection of the excitation light, the filtering module also includes a second filter 8 located between the photoexcitation port and the second photodetector 6, which is used to filter out the excitation light.

[0090] Example 5: This example provides a sensing system based on a solid-state spin color center, as shown in Figure 10, including: a sensing structure based on a solid-state spin color center as in Example 4 and an excitation light source 10; the excitation light source 10 is connected to the optical input terminal 11 of the optical waveguide 1 for inputting excitation light.

[0091] The excitation light source 10 can be a laser or an LED light source. The excitation light source 10 may also include components for processing the light generated by the light source, such as components for filtering and collimation. In this embodiment, the excitation light source 10 is a laser source.

[0092] It also includes an analog circuit module 20 and a control module 30. The analog circuit module 20 is connected to the photodetector module and the excitation light source 10. The control module 30 is connected to the analog circuit module 20. The analog circuit module 20 receives the detection signal transmitted by the photodetector module. The detection signal can be at least one measurement electrical signal and one reference electrical signal, or at least one fluorescence electrical signal and one excitation photodetector signal. The analog circuit module 20 performs differential processing on each measurement electrical signal and one reference electrical signal, or on each fluorescence electrical signal and one excitation photodetector signal. The analog circuit module 20 also processes the received excitation photodetector signal and transmits it to the control module 30. The control module 30 transmits a control signal to the analog circuit module 20 according to the excitation photodetector signal. The analog circuit module 20 controls the driving of the excitation light source 10 according to the control signal to control the output power of the excitation light source 10, thereby making the generated excitation light in a stable state or a desired state.

[0093] The analog circuit module 20 includes at least a differential circuit for differential processing and a circuit for controlling the driving of the excitation source 10, such as a circuit that drives the excitation source 10 by controlling the current. The processing of the electrical signal by the analog circuit module 20 may, exemplarily, include conditioning the electrical signal. The circuit for conditioning includes one or more of the following: a transimpedance amplifier, a voltage amplifier, a filter, an analog-to-digital converter, etc. These are commonly used circuits in the art and will not be described in detail here.

[0094] In the presence of microwave antenna 5, a microwave generation module 40 is also included for transmitting microwaves to microwave antenna 5. When there are multiple microwave antennas 5, the microwave generation module 40 may, for example, include multiple microwave generation units. Each microwave generation unit includes a microwave source, a microwave switch, a microwave amplifier, and a microwave circulator connected in sequence. Each microwave generation unit transmits the generated microwaves to the corresponding microwave antenna 5.

[0095] The system also includes a lock-in amplifier 50 and a data processing module 60. The lock-in amplifier 50 is connected to the microwave generation module 40 and the analog circuit module 20, and is used to transmit microwave modulation signals to the microwave generation module 40 and demodulate the differential signals or fluorescent signals transmitted to it from the analog circuit module 20. The data processing module 60 is used to receive the demodulated signals from the lock-in amplifier 50. The data processing module 60 plots ODMR spectra based on the demodulated signals and calculates the measurements to be taken, such as magnetic fields, temperature, and current in the environment. Further noise reduction can be achieved through microwave modulation, such as microwave frequency modulation, and demodulation of differential signals or fluorescent signals, for example, reducing 1 / f noise and improving the signal-to-noise ratio.

[0096] Example 6: This example provides a detection method based on solid-state spin centers, including:

[0097] At least one light leakage region is provided between the optical input end and the optical output end of an optical waveguide, and each light leakage region is used to leak out a portion of the light transmitted in the optical waveguide; the optical output end of the optical waveguide and each light leakage region are used as optical excitation ports, and a sensor is provided on at least one of the optical excitation ports in a one-to-one correspondence, each sensor containing a solid-state spin color center.

[0098] Place the sensitive object that needs to be tested in the test environment;

[0099] An excitation light is input to the light input terminal, and the excitation light is used to excite the solid spin center to produce fluorescence.

[0100] Perform detection using any of the following methods:

[0101] Method 1: Detect the fluorescence generated by at least one sensitive object to obtain a fluorescence electrical signal, and obtain the quantifier within the measurement range of the corresponding sensitive object based on the fluorescence electrical signal; or detect the fluorescence generated by at least one sensitive object to obtain a fluorescence electrical signal, and for each sensitive object, irradiate it with microwaves, obtain the fluorescence electrical signal at each frequency by scanning the microwave frequency, then plot ODMR spectra based on the fluorescence electrical signals, and obtain the quantifier within the measurement range of the corresponding sensitive object based on the ODMR spectra.

[0102] Method 2: Detect the excitation light emitted from one of the photoexcitation ports to obtain the excitation photoelectric signal, and detect the fluorescence generated by at least one sensor to obtain the fluorescence electrical signal. For each sensor, the detected fluorescence electrical signal and the excitation photoelectric signal are differentially processed to obtain a differential signal. The measurand within the measurement range of the corresponding sensor is obtained based on the differential signal. Alternatively, detect the excitation light emitted from one of the photoexcitation ports to obtain the excitation photoelectric signal, and detect the fluorescence generated by at least one sensor to obtain the fluorescence electrical signal. For each sensor, microwaves are also irradiated onto it. By scanning the microwave frequency, the fluorescence electrical signal at each frequency is obtained. The differential signal between the fluorescence electrical signal and the excitation photoelectric signal at each frequency is calculated. Then, ODMR spectra are plotted based on the differential signals, and the measurand within the measurement range of the corresponding sensor is obtained based on the ODMR spectra.

[0103] Method 3: In the same environment, detect the fluorescence generated by at least one sensitive object to obtain a fluorescence electrical signal. Irradiate microwaves to at least one of the sensitive objects and scan the microwave frequency. Use the detected fluorescence electrical signal as the measurement electrical signal. Do not irradiate microwaves to the remaining sensitive object and use the detected fluorescence electrical signal as the reference electrical signal. For each sensitive object irradiated with microwaves, perform differential processing between its measurement electrical signal and the reference electrical signal to obtain the differential signal at each frequency. Then, plot the ODMR spectrum based on the differential signal and obtain the quantifier within the measurement range of the corresponding irradiated sensitive object based on the ODMR spectrum.

[0104] In Method 1, without microwaves, the magnetic field value can be calculated using a calibration curve between the magnetic field and the fluorescence signal. With microwaves applied, ODMR detection can be used, and the desired parameters, such as magnetic field and temperature, can be measured based on the resonance frequency or zero-field splitting on the ODMR spectral lines. Multiple sensors can be configured and positioned one-to-one at the photoexcitation port to achieve multi-point measurements, depending on the detection requirements.

[0105] In Method 2, by adding a detector for the excitation light, the difference between the fluorescence electrical signal and the detection signal of the excitation light is used to calculate the metric. This difference reduces noise caused by the instability of the excitation source, improving detection accuracy. Furthermore, this method allows for the adjustment of the power of the excitation light input to the optical input terminal based on the excitation photoelectric signal, thereby stabilizing the excitation light and further reducing noise.

[0106] In Method 3, when setting up multiple sensors, one of the sensors is not irradiated with microwaves. The fluorescence signal detected by the sensor is used as a reference signal, and the fluorescence signal detected by the sensor irradiated with microwaves is used as the measurement signal. The measurement is calculated by the difference between the measurement signal and the reference signal. Through the difference, the noise caused by the instability of the excitation source can be reduced, as well as the background noise caused by factors such as vibration and temperature in the fluorescence generated by the solid spin center and in the same environment. The reduction of noise also helps to improve the sensitivity of resonance peak identification in ODMR detection.

[0107] In either Method 1 or Method 3, the detection of the excitation light emitted from one of the optical excitation ports can be included, thereby adjusting the power of the excitation light input to the optical input terminal based on the acquired excitation photoelectric signal, so that the excitation light is in a stable state and noise is further reduced.

[0108] The light leakage area in this embodiment can be obtained according to any one of the methods in Embodiment 1 to Embodiment 3, which will not be described in detail here.

[0109] The detection method in this embodiment can be implemented based on the sensing system in Embodiment 5.

[0110] The above embodiments are merely illustrative of the principles and effects of this application and are not intended to limit this application. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this application. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this application should still be covered by the claims of this application.

Claims

1. A probe based on a solid-state spin color center, characterized in that, include: An optical waveguide has an optical input end and an optical output end, and at least one light leakage region is provided on the portion located between the optical input end and the optical output end. Each light leakage region is used to leak out a portion of the light transmitted in the optical waveguide, and the optical output end of the optical waveguide and each light leakage region serve as optical excitation ports. It also includes at least one sensor disposed on at least one of the light excitation ports, each sensor containing a solid spin color center.

2. The probe based on a solid-state spin color center according to claim 1, characterized in that: The light leakage area is formed by changing the shape of the core layer and cladding interface, or by exposing at least a portion of the cladding cross-section to the outside, or by exposing the outer surface of the core layer to the outside, or by exposing at least a portion of the core layer cross-section to the outside.

3. The probe based on a solid-state spin color center according to claim 1, characterized in that: At least one photoexcitation port is provided with a focusing structure for focusing the light emitted from the photoexcitation port or the light generated by the sensor.

4. The probe based on a solid-state spin color center according to claim 1, characterized in that: The light leakage area is filled with a filler having a set refractive index.

5. The probe based on a solid-state spin color center according to claim 4, characterized in that: The refractive index of the filler changes with temperature, and a temperature control device is provided to regulate the temperature of the filler.

6. The probe based on a solid-state spin color center according to any one of claims 1 to 5, characterized in that: The solid-state spin color center is one of the following: diamond nitrogen-vacancy color center, diamond germanium-vacancy color center, diamond silicon-vacancy color center, silicon carbide double-vacancy color center, silicon carbide silicon-vacancy color center, or hexagonal boron nitride boron-vacancy color center.

7. A sensing structure based on a solid-state spin color center, characterized in that, include: The probe based on a solid-state spin center as described in any one of claims 1 to 6, wherein the optical input end of the optical waveguide is used to input excitation light, and the excitation light is used to excite the solid-state spin center to generate fluorescence; Photoelectric detection module, including at least one sensor facing the sensor and corresponding to at least one sensor. There is one less first photodetector. Each first photodetector is used to detect the fluorescence generated by the corresponding sensitive object and output a fluorescence electrical signal. The filtering module includes a first filter located between each sensor and a corresponding first photodetector for filtering out fluorescence.

8. The sensing structure based on a solid-state spin color center according to claim 7, characterized in that: The photoelectric detection module further includes at least one second photodetector facing at least one light excitation port and corresponding one-to-one with at least one light excitation port. Each second photodetector is used to detect the excitation light emitted from the corresponding light excitation port and output an excitation photoelectric signal.

9. The sensing structure based on a solid-state spin color center according to claim 8, characterized in that: The filtering module also includes a second filter located between each second photodetector and the corresponding photoexcitation port, for filtering out the excitation light.

10. The sensing structure based on a solid-state spin color center according to claim 8 or 9, characterized in that: A light adjustment element is also provided between each second photodetector and the corresponding light excitation port to adjust the intensity of the excitation light entering the corresponding second photodetector.

11. The sensing structure based on a solid-state spin color center according to claim 7, characterized in that: It also includes a microwave radiation module, with at least a portion of the sensitive objects located within the radiation zone of the microwave radiation module.

12. A sensing system based on a solid-state spin color center, characterized in that, include: An excitation source and a sensing structure based on a solid-state spin color center as described in any one of claims 7-11; the excitation source is connected to the optical input end of an optical waveguide for inputting excitation light.

13. The sensing system based on a solid-state spin color center according to claim 12, characterized in that: It also includes an analog circuit module and a control module connected to each other. The analog circuit module is also connected to the excitation light source and the photodetector module. When the photodetector module collects the excitation light from the light excitation port and obtains the excitation photoelectric signal, the analog circuit module processes the excitation photoelectric signal from the photodetector module and transmits it to the control module. The control module is used to transmit a control signal to the analog circuit module according to the excitation photoelectric signal. The analog circuit module controls the driving of the excitation light source according to the control signal.

14. The sensing system based on a solid-state spin color center according to claim 13, characterized in that: The analog circuit module also performs differential processing on each of the at least one fluorescent electrical signal transmitted by the photoelectric detection module and one excitation photoelectric signal.

15. The sensing system based on a solid-state spin color center according to claim 13, characterized in that: When a microwave radiation module is present and at least one sensitive object is not irradiated with microwaves, the fluorescence electrical signal of the irradiated sensitive object detected by the photoelectric detection module is used as the measurement electrical signal, and the fluorescence electrical signal of the unirradiated sensitive object is used as the reference electrical signal. The analog circuit module also performs differential processing on each of the at least one measurement electrical signal transmitted by the photoelectric detection module and one reference electrical signal.

16. The sensing system based on a solid-state spin color center according to any one of claims 13 to 15, characterized in that: When a microwave radiation module is present, a microwave generation module is also included, which generates microwaves and transmits them to the microwave radiation module. A lock-in amplifier and a data processing module are also connected to each other. The lock-in amplifier is also connected to the microwave generation module and the analog circuit module, and is used to transmit microwave modulation signals to the microwave generation module and demodulate the fluorescent electrical signals or differential signals transmitted to it by the analog circuit module. The data processing module is used to receive the demodulated signals from the lock-in amplifier.

17. A detection method based on solid-state spin color centers, characterized in that, The method includes: At least one light leakage region is provided between the optical input end and the optical output end of an optical waveguide, and each light leakage region is used to leak out a portion of the light transmitted in the optical waveguide; the optical output end of the optical waveguide and each light leakage region are used as optical excitation ports, and a sensor is provided on at least one of the optical excitation ports in a one-to-one correspondence, each sensor containing a solid-state spin color center. Place the sensitive object that needs to be tested in the test environment; An excitation light is input to the light input terminal, and the excitation light is used to excite the solid spin center to produce fluorescence. Perform detection using any of the following methods: Method 1: Detect the fluorescence emitted by at least one sensitive object to obtain a fluorescence electrical signal, and then obtain the analyte within the measurement range of the corresponding sensitive object based on the fluorescence electrical signal; or detect the fluorescence emitted by at least one sensitive object to obtain a fluorescence electrical signal, and for each sensitive object, irradiate it with microwaves, obtain the fluorescence electrical signal at each frequency by scanning the microwave frequency, then plot ODMR spectra based on the fluorescence electrical signals, and obtain the analyte within the measurement range of the corresponding sensitive object based on the ODMR spectra. Measurement; Method 2: Detect the excitation light emitted from one of the photoexcitation ports to obtain the excitation photoelectric signal, and detect the fluorescence generated by at least one sensor to obtain the fluorescence electrical signal. For each sensor, the detected fluorescence electrical signal and the excitation photoelectric signal are differentially processed to obtain a differential signal. The measurand within the measurement range of the corresponding sensor is obtained based on the differential signal. Alternatively, detect the excitation light emitted from one of the photoexcitation ports to obtain the excitation photoelectric signal, and detect the fluorescence generated by at least one sensor to obtain the fluorescence electrical signal. For each sensor, microwaves are also irradiated onto it. By scanning the microwave frequency, the fluorescence electrical signal at each frequency is obtained. The differential signal between the fluorescence electrical signal and the excitation photoelectric signal at each frequency is calculated. Then, ODMR spectra are plotted based on the differential signals, and the measurand within the measurement range of the corresponding sensor is obtained based on the ODMR spectra. Method 3: In the same environment, detect the fluorescence generated by at least one sensitive object to obtain a fluorescence electrical signal. Irradiate microwaves to at least one of the sensitive objects and scan the microwave frequency. Use the detected fluorescence electrical signal as the measurement electrical signal. Do not irradiate microwaves to the remaining sensitive object and use the detected fluorescence electrical signal as the reference electrical signal. For each sensitive object irradiated with microwaves, perform differential processing between its measurement electrical signal and the reference electrical signal to obtain the differential signal at each frequency. Then, plot the ODMR spectrum based on the differential signal and obtain the quantifier within the measurement range of the corresponding irradiated sensitive object based on the ODMR spectrum.

18. The detection method based on solid-state spin color centers according to claim 17, characterized in that: In either Method 1 or Method 3, the excitation light emitted from one of the optical excitation ports is also detected to obtain an excitation photoelectric signal. For any of the three methods, the power of the excitation light input to the optical input terminal is also adjusted according to the excitation photoelectric signal.

Images