Probe, sensing structure, system and method based on solid-state spinning color center

Abstract

The invention provides a probe, a sensing structure, a system and a method based on a solid-state spinning color center, and the probe comprises an optical waveguide which is provided with a light input end and a light output end, at least one light leakage region is arranged on a part between the light input end and the light output end, each light leakage region is used for leaking a part of light transmitted in the optical waveguide, and the light leakage region is used for leaking a part of light transmitted in the optical waveguide; the light output end of the optical waveguide and / or each light leakage area are / is used as a light excitation port; the at least one sensitive body is arranged on at least one optical excitation port in a one-to-one correspondence manner, and each sensitive body comprises a solid-state spinning color center. Therefore, beam splitting of light is achieved, and the light beam splitting structure is greatly simplified. Multi-point detection can be realized at a plurality of optical excitation ports through the photoluminescence effect of the solid-state spinning color center; the excitation light is detected at the light excitation port, the input power of the excitation light can be regulated and controlled according to a detected signal, and the stability of the excitation light is further improved; and noise reduction can be realized through differential processing, and the detection accuracy is improved.

Description

Technical Field

[0001] This invention 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

[0002] 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.

[0003] 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. Summary of the Invention

[0004] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a probe, sensing structure, system and method based on a solid-state spin color center, in order to solve the problem that the optical beam splitting structure occupies a large space and is not conducive to its application in miniaturized sensors.

[0005] To achieve the above and other related objectives, the present invention 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 optical excitation ports, and further comprising at least one sensor disposed corresponding to at least one optical excitation port therein, each sensor comprising a solid-state spin color center.

[0006] Furthermore, 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.

[0007] Furthermore, a focusing structure is provided at the at least one photoexcitation port to focus the light emitted from the photoexcitation port or the light generated by the sensor.

[0008] Furthermore, the light leakage area is filled with a filler having a set refractive index.

[0009] Furthermore, the refractive index of the filler changes with temperature, and a temperature control device is provided to regulate the temperature of the filler.

[0010] Furthermore, 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.

[0011] To achieve the above and other related objectives, the present invention also provides a sensing structure based on a solid-state spin color center, comprising: a probe based on a solid-state spin color 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 color center to generate fluorescence; 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; The filtering module includes a first filter located between each sensor and a corresponding first photodetector for filtering out fluorescence.

[0012] Furthermore, the photoelectric detection module also 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.

[0013] Furthermore, the filtering module also includes a second filter located between each second photodetector and the corresponding photoexcitation port, for filtering out the excitation light.

[0014] Furthermore, a light adjustment element is provided between each second photodetector and its corresponding light excitation port to adjust the intensity of the excitation light entering the corresponding second photodetector.

[0015] Furthermore, 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.

[0016] To achieve the above and other related objectives, the present invention also provides a sensing system based on a solid-state spin color center, comprising: a sensing structure based on a solid-state spin color center as described in any of the preceding claims, and an excitation light source; the excitation light source is connected to the optical input end of an optical waveguide for inputting excitation light.

[0017] Furthermore, it also includes connected analog circuit modules and control modules. The analog circuit modules are also connected to the excitation light source and the photoelectric detection module. When the photoelectric detection 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 photoelectric detection module and transmits it to the control module. The control module is used to transmit control signals 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 signals.

[0018] Furthermore, 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.

[0019] Furthermore, 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.

[0020] Furthermore, 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.

[0021] To achieve the above and other related objectives, the present invention also provides a detection method based on solid-state spin centers, comprising: 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 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. 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.

[0022] Furthermore, 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.

[0023] As described above, the probe, sensing structure, system, and method based on solid-state spin centers of the present invention have the following beneficial effects: 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. 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. 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

[0024] Figure 1 The diagram shown is a schematic diagram of the first structure of the probe of the present invention; Figure 2 The diagram shown is a second structural schematic of the probe of the present invention; Figure 3 The diagram shown is a third structural schematic of the probe of the present invention; Figure 4 The diagram shown is a structural schematic of the closed cavity of the present invention. Figure 5 This is a schematic diagram of the fourth structure of the probe of the present invention; Figure 6 This is a schematic diagram of the fifth structure of the probe of the present invention; Figure 7 The diagram shown is a first structural schematic of the sensing structure of the present invention. Figure 8 The diagram shown is a second structural schematic of the sensing structure of the present invention. Figure 9 The diagram shows a third structural schematic of the sensing structure of the present invention. Figure 10 The diagram shown is a schematic of the sensing system of the present invention.

[0025] Component labeling: 1—Optical waveguide; 11—Optical input terminal; 12—Optical output terminal; 13—Light leakage area; 131—Filling material; 14—Focusing structure; 15—Sealed cavity; 151—Sealed area; 152—Filling hole; 16—Temperature control; 17—Core layer; 18—Cladding layer; 19—Coating layer; 2—Sensor; 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

[0026] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, unless otherwise specified, the following embodiments and features described therein can be combined with each other.

[0027] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Therefore, the illustrations only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the 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.

[0028] Example 1: As Figure 1 As shown, this embodiment 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 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 optical excitation ports, and including at least one sensor 2 disposed corresponding to at least one optical excitation port therein, each sensor containing a solid-state spin color center.

[0029] Figure 1 An example is given of a light leak area; the case of multiple light leak areas is as follows: Figure 2 As shown, the structures of the light leakage regions can be identical or different, and they are arranged along the axis of the optical waveguide.

[0030] For example, Figure 1 As shown, the sensor 2 is placed at the optical output end of the optical waveguide. The sensor 2 can be connected to the end face of the optical output end by adhesive bonding, receiving excitation light input from the optical input end and output from the optical output end, and thus generating fluorescence under the excitation of the excitation light. The end face of the optical output end can be set as a plane, an arc-shaped convex surface, or a conical surface.

[0031] Therefore, by setting a light leakage region, the light is split into beams, and the output is achieved by the light output end and at least one light leakage region as the light excitation port. This embodiment only uses an optical waveguide to achieve beam splitting, which greatly simplifies the optical beam splitting structure. Moreover, the size of the optical waveguide is small, generally in the micrometer range, and the size and position of the light leakage region can be flexibly adjusted as needed, enabling its application in integrated and miniaturized sensors.

[0032] For a typical optical waveguide, from the inside out, it includes a core layer 17 and a cladding layer 18. The outer surface of the core layer can be completely covered by the cladding layer, such as in cylindrical optical fibers or embedded strip waveguides. It can also have a layered structure, such as a planar waveguide with a core layer in the middle and cladding layers on the top and bottom, or a strip waveguide with the core layer embedded within the cladding layer or located on the surface of the cladding layer. Optical fibers can be further divided into bare fibers and fibers with protective layers. For bare fibers, a coating layer is applied to the outside of the cladding layer, while for fibers with protective layers, a protective layer covers the outside of the cladding layer. Figure 1 The example shown is a bare optical fiber including a coating layer 19. Regardless of the type of optical waveguide, the principle of light transmission within it is the same: light propagates in the core layer and undergoes total internal reflection at the interface between the core and cladding, preventing light leakage. In this embodiment, a light leakage region is provided between the optical input and output ends to allow some of the light propagating in the waveguide to leak out, thus achieving light splitting. The optical fiber in this embodiment can be single-mode or dual-mode fiber.

[0033] In this embodiment, a section of the optical waveguide is processed to change the shape of the core-cladding interface in the waveguide section where the leakage region is located. This alters the incident angle of light at the core-cladding interface in this section, thereby changing the total internal reflection condition and allowing light to leak out from the cladding. For example, in optical fiber, the area to be processed can be heated and stretched to change the incident angle of light at the core-cladding interface, thus changing the total internal reflection condition and allowing some light in the core to leak out. Figure 1 After the optical fiber is stretched, the light leakage area is hourglass-shaped. Figure 1The example demonstrates first removing the outer layer of the part to be processed, such as a coating or protective layer. Removal methods include scraping, peeling, polishing, or heating. Then, stretching is performed to 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 core-cladding interface of the waveguide segment where the light leakage region is located can also be changed during the waveguide forming stage. For example, the cladding-core interface of the light leakage region can be made into an hourglass shape or similar. Figure 9 The cone shape shown is an example.

[0034] Alternatively, after the cladding is exposed to the outside, at least part of the cladding can be removed so that some of the light entering the cladding can leak out. This method may result in less leaked light and is more suitable for situations where the required light intensity is weak.

[0035] In this embodiment, the setting of the light leakage region not only simplifies the beam splitting structure, but also allows the light propagating in the optical waveguide to be directly separated from the light leakage region, without the need to introduce the beam splitting fiber for separation as in an optical fiber beam splitter. This can effectively reduce noise and improve stability.

[0036] To increase the collection of light leakage in the leakage region and minimize its size, this embodiment employs methods such as stretching the optical fiber to allow light to leak out and obtain the desired leakage light intensity. This places certain requirements on the stretching length of the optical fiber; a larger stretching length is needed for the required light intensity, but because the optical fiber is relatively thin, excessive stretching can easily lead to breakage. Therefore, it is possible to... Figure 2 As shown, filler 131 is filled in the light leakage area. The filler has a set refractive index to change the original refractive index, increase the collection efficiency of leaked light, or improve the light emission ratio. Furthermore, by adjusting the size of the filler, the size and light leakage efficiency of the light leakage area can be flexibly controlled. The formation of the filler acts similarly to an optical lens. Different refractive indices of the filler 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 fillers, [the following is an example / example] can be used. Figure 3 The enclosed cavity 15 shown seals off the light leakage area. The shape of the filler is configured to converge light, for example, as a lens structure with a convex surface.

[0037] Figure 2 An example is provided whereby the sensor 2 is fixed to the light leakage area using a solid filler such as optical adhesive or PDMS. This not only fixes the sensor but also fills the light leakage area with the optical adhesive or PDMS, thereby improving the collection efficiency of the leaked light and the excitation efficiency of the solid spin center.

[0038] 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 is an aggregate with a bulk, granular, or powdery structure. In this embodiment, the sensing element is exemplarily a diamond containing nitrogen-vacancy color centers, with a size in the nanometer or micrometer range.

[0039] 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.

[0040] The probe in this embodiment uses an optical waveguide whose size 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.

[0041] Example 2: In this example, a section of the optical waveguide is processed to expose the outer surface of the core layer. For example, for optical fibers, this can be done by scraping, stripping, or polishing; for other types of waveguides, the cladding is removed during the forming stage using processes such as etching. Figure 2 As shown, after removing the cladding, some light in the core layer is refracted out, forming a light leakage region. In this embodiment, it can also be done as follows... Figure 3 As shown, the core layer is further partially removed so that at least a portion of the core layer's cross-section is exposed to the outside.

[0042] In this embodiment, a light-concentrating structure 14 is also 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.

[0043] 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, for example, Figure 2 , Figure 4 , Figure 8 , Figure 9 The TIR lens (i.e., a total internal reflection lens) shown has an incident surface that is a groove recessed into the lens body (e.g., Figure 4 (The area marked with a dashed line) allows the light excitation port to be at least partially positioned within the groove of the TIR lens (e.g., ...). Figure 2 , Figure 9As shown in the figure, or within the lens body, holes or slots can be drilled in the sidewall of the groove or on the lens body (only the hole or slot structure inside the TIR lens is shown in the figure) to insert or insert the optical waveguide, so that part or all of the light excitation port is located inside the groove or within the lens body; alternatively, the groove of the TIR lens can be directly aligned with the filler 131 of the light leakage area, and the filler 131 can be built into the groove of the lens; or the light excitation port can be housed within the lens body, forming an integral structure with the condenser lens. The TIR lens performs total internal reflection to focus the light, and the light is emitted from the other end face to achieve the collection of the light beam or to obtain the light of the required intensity. Other lenses can also be used, such as Figure 7 The hemispherical lens shown Figure 3 or Figure 10 The compound parabolic condenser and aspherical lens shown can all converge light. Slots or holes 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 and integrated with the condenser lens into a single structure.

[0044] Sensitive body 2 can also be like Figure 2 , Figure 7 , Figure 10 As shown, it can be located inside the condenser lens along with the light excitation port; alternatively, 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 by... Figure 8 As shown, 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.

[0045] Concentrating structures can also be like Figure 5 As shown, this is a cavity structure with an opening, where the light excitation port is located within the cavity. The cavity can be made of metal, with its inner wall reflecting light and allowing it to exit through the opening, thus concentrating the light. Alternatively, the cavity can be made of non-metallic material, with its inner wall covered by a light-reflecting film to reflect light and allow it to exit through the opening. This light-reflecting film can be a metallic film or a non-metallic high-reflectivity film, such as titanium dioxide, zinc oxide, or other metal oxide materials. The sensor can be, for example... Figure 5 The image shown is located inside the cavity, or it can be located outside the cavity and facing the opening.

[0046] To enhance the adjustability of the leaked light intensity, the filler 131 filling the leaked area 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. Figures 3-4As shown, for liquid fillers, a closed cavity 15 can be used to seal the light leakage area. A temperature control device 16, such as a semiconductor cooling chip, a non-metallic heating element, or a thermally conductive metal material, is installed inside or outside the closed cavity to regulate the temperature of the filler, thereby obtaining the required light output and maintaining the stability of the light output. Figure 3 A temperature control unit 16 is installed outside the sealed cavity, located on the side of the optical waveguide opposite to the light leakage area. By adjusting the temperature of the temperature control unit 16, the refractive index of the filling liquid changes, thereby adjusting the light emission ratio of the light leakage area and thus regulating the intensity of the leaked light. For solid fillers, a sealed cavity can be selectively added or omitted. For example, cured PDMS is filled into the light leakage area by filling the PDMS solution with high temperature curing, thus filling the light leakage area in solid form.

[0047] In this embodiment, the enclosed cavity 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 is inserted into the cavity, it is sealed by sealing the gaps at both ends of the cavity with adhesive. Figure 3 , Figure 4 The sealing area 151 is filled with liquid, and the liquid is injected into the light leakage area in the middle of the cavity through the sealing area by an extremely fine injection needle. The sealed cavity after filling with liquid can be sealed again to improve the sealing performance.

[0048] It is also possible to Figure 4 As shown, a filling hole 152 is opened on the wall surface of the sealed cavity near the light leakage area. After the sealed cavity is closed, filling liquid is injected into the light leakage area inside the cavity through the filling hole 152. After filling, the filling hole can be sealed with adhesive. Figure 4 The example provided shows a temperature control unit 16 installed in a sealed cavity, facilitating the placement of the entire sealed cavity within a condenser lens. The temperature control unit can employ the aforementioned structure, or it can be made of a smaller heat-conducting wire or strip and connected to an external cooling or heat dissipation device. Alternatively, a semiconductor temperature control layer can be deposited directly on the inner wall of the sealed cavity and connected to an external cooling or heat dissipation device. A spacer can also be provided between the temperature control unit and the optical waveguide to prevent the filling liquid from seeping into the temperature control unit.

[0049] When the sensor is located in the light leakage region, and the light leakage region is filled with a filler material, and the temperature of the filler material is adjusted, the sensor and the filler material need to be kept at a certain distance. For example, one of the sensor and the light leakage region can be placed inside the light-concentrating structure, and the other outside the light-concentrating structure, in order to reduce the impact of temperature on the photoluminescence of the solid-state spin color center. An example is shown below. Figure 4 As shown, the sensor is located inside the light-concentrating structure, while the light-leaking area is located outside the light-concentrating structure.

[0050] Example 3: In this example, by cutting or misaligning the optical waveguide, at least a portion of the core layer cross-section is exposed to the outside, thereby forming a light leakage region 13. For example... Figures 5-6 As shown, this represents the exposed portion of the core layer cross-section of the optical waveguide. Figure 5 The method of partial truncation is adopted. Figure 6 The two optical waveguide ends are staggered and connected, and the connection method can be direct contact or fusion welding. Figure 8 As shown, the entire core cross-section is exposed to the outside.

[0051] The light leakage area in this embodiment can also be treated with the filling material as in Embodiment 1 or 2, which will not be described in detail here.

[0052] Figure 6 This is a top view taken from the condenser lens side. Through misalignment, a portion of the core layer's cross-section is aligned with a portion of the cladding's cross-section, allowing some light from the core layer to enter the cladding and then leak out.

[0053] Figure 8 Alternatively, the sensitive element 2 can be placed in the light leakage area 13, and located between the broken sections.

[0054] Example 4: This example provides a sensing structure based on a solid-state spin color center, such as... Figures 7-9 As shown, it includes a probe, a photoelectric detection module, and a filtering module as described in any of the embodiments 1 to 3. The photoelectric detection module includes at least one first photodetector 3 facing the sensitive object and corresponding to at least one sensitive object. Each first photodetector 3 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 4 located between each sensitive object and the corresponding first photodetector for filtering out fluorescence.

[0055] For example Figure 7 As shown, two sensors are configured, one located at the light output end and the other at a light leakage region. Therefore, the fluorescence signal of each sensor 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, it can be as follows... Figure 2 As shown, multiple light leakage zones are set up, and a sensor is set up in each light leakage zone to achieve multi-point measurement.

[0056] Alternatively, a microwave radiation module can be set up to radiate microwaves onto at least a portion of the sensitive objects. For each irradiated sensitive object, 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 corresponding range of the sensitive object. The measured range for each sensitive object includes at least the measurement area 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.

[0057] Microwaves can be selectively irradiated onto at least one sensitive object, and the microwave frequency can be scanned. The detected fluorescence signal is used as the measurement signal. For the remaining sensitive object, no microwaves are irradiated, and the detected fluorescence signal is used as the reference signal. For each irradiated sensitive object, 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 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, using irradiated and non-irradiated sensitive objects for fluorescence differential processing can reduce noise from the excitation source, as well as background noise in the generated fluorescence and the environment, improving measurement accuracy and stability. Furthermore, noise reduction also helps improve the sensitivity of resonance peak identification in ODMR detection.

[0058] 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 is used to detect the excitation light emitted from the corresponding light excitation port and output an excitation photoelectric signal. For example... Figure 8 As shown, the excitation light is detected in one of the light leakage regions.

[0059] Each filter can correspond to one or more photodetectors. The diagram illustrates a one-to-one correspondence; for multiple adjacent sensors, a single filter can be used. The microwave radiation module can consist of one or more microwave antennas 5. Multiple sensors can be located within the radiation area of ​​one microwave antenna, or they can correspond one-to-one with the radiation areas of multiple microwave antennas. Microwave antennas can be used as follows: Figures 7-9 The coplanar waveguide antenna in the middle can also be such as Figure 10 The spiral antenna in the design can also be other types of antennas.

[0060] The photoelectric detection module, filter module, and focusing structure can be interconnected as follows: Figure 9 The gap setting shown can also be as follows: Figure 7 , Figure 8 , Figure 10The fit settings are shown.

[0061] The power of the excitation light input to the optical input terminal 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.

[0062] Alternatively, the fluorescence electrical signal and the excitation photoelectric signal from each sensor can be differentially processed, and the differential signal can be used to perform the calculation of the measurement to achieve noise reduction.

[0063] It is also possible to Figure 10 As shown, by setting up a sensor that is irradiated with microwaves and a sensor that is not irradiated with microwaves, 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 is controlled by using the excitation photoelectric signal.

[0064] In differential noise reduction, to better reduce common-mode noise, the excitation photoelectric signal and the fluorescence 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 beams, the fluorescence intensity is generally weaker than the excitation light intensity. Therefore, the amount of excitation light needs to be adjusted to control its detection intensity to meet the detection requirements. To achieve this adjustment of the detected excitation light, the method of filling the leakage region with filler material, as described in Example 1 or Example 2, can also be used as follows... Figures 9-10 As shown, a light adjustment element 7 is disposed 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, and the amount of light is adjusted by adjusting the light transmission area, such as an aperture; or it can be a light attenuator that reduces the light transmission intensity by absorbing, scattering, or reflecting light. When a focusing structure 14 is provided, the light adjustment element 7 can be disposed between the focusing structure 14 and the second photodetector 6 as shown in the figure; or when a focusing lens is used for focusing, the adjustment element can be disposed between the light excitation port and the focusing lens.

[0065] 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.

[0066] Example 5: This example provides a sensing system based on solid-state spin color centers, such as... Figure 10 As shown, it includes: a sensing structure based on a solid-state spin color center as in Embodiment 4, and an excitation light source 10; the excitation light source 10 is connected to the optical input terminal 11 of the optical waveguide for inputting excitation light.

[0067] The excitation light source 10 can be a laser or an LED light source, and may also include components for processing the light generated by the light source, such as filtering and collimation. In this embodiment, the excitation light source 10 is a laser source.

[0068] It also includes an analog circuit module 20 and a control module 30. The analog circuit module 20 is connected to the photoelectric detection 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 photoelectric detection 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 photoelectric 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 photoelectric signal. The analog circuit module 20 also processes the received excitation photoelectric 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 photoelectric signal. The analog circuit module 20 controls the driving of the excitation light source 10 according to the control signal to control the emission power of the excitation light source, thereby making the generated excitation light in a stable state or a desired state.

[0069] The analog circuit module 20 includes at least a differential circuit for differential processing and a circuit for controlling the excitation light source drive, such as a circuit that drives the excitation light source by controlling the current. The processing of the electrical signal by the analog circuit module 20 may exemplary include conditioning the electrical signal, and 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.

[0070] In the presence of a microwave antenna, a microwave generation module 40 is also included for transmitting microwaves to the microwave antenna 5. When there are multiple microwave antennas, 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.

[0071] 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.

[0072] Example 6: This example provides a detection method based on solid-state spin centers, including: 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 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. 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.

[0073] 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.

[0074] 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.

[0075] 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.

[0076] 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.

[0077] 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.

[0078] The detection method in this embodiment can be implemented based on the sensing system in Embodiment 5.

[0079] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

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 in 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. 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 corresponding to at least one photoexcitation port therein, each sensor comprising a solid-state 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; 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; 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: The sensing structure and excitation source based on solid-state spin color centers as described in any one of claims 7-11; The excitation light source is connected to the optical input end of the optical waveguide and is used to input 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 photoelectric detection module. When the photoelectric detection 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 photoelectric detection 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 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. 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.

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