Diamond nv-center magnetic force detection device and system

Abstract

The application is suitable for the field of diamond color center quantum sensing technology, and provides a diamond NV color center magnetic force detection device and system, which comprises three mutually perpendicular detection modules, an optical fiber, a microwave module and a fluorescence transmission module. Each detection module comprises two magnetic flux concentrators, a diamond sample, a first focusing mirror, a second focusing mirror, a filter and a photodetector. The diamond sample is an NV color center ensemble. The two magnetic flux concentrators are respectively in contact with the upper surface and the lower surface of the diamond sample. The first focusing mirror and the second focusing mirror are respectively arranged on the two sides of the diamond sample. The diamond sample is connected with the microwave module. The laser in the optical fiber is focused on the diamond sample through the first focusing mirror. The fluorescence generated by the diamond sample under the action of the laser and the microwave provided by the microwave module is collected by the second focusing mirror, passes through the filter, and is introduced into the fluorescence transmission module through the photodetector. The application can realize real-time detection of a vector magnetic field.

Description

Technical Field

[0001] This application belongs to the field of diamond color center quantum sensing technology, and particularly relates to a magnetic detection device and system for diamond NV color centers. Background Technology

[0002] A diamond NV center (nitrogen-vacancy center) is a point defect structure in a diamond crystal where a nitrogen atom replaces a carbon atom, and the adjacent carbon atom is missing, forming a hole. A diamond NV center is a solid-state single-spin quantum system with various excellent properties. Solid-state spin can be based on the characteristics of electron spin and atomic nuclear spin, and through precise manipulation of atomic spin states, high-sensitivity measurements of various physical quantities (including electric fields, magnetic fields, temperature, ion concentration, etc.) can be achieved. Therefore, diamond NV monochromatic center samples or diamond NV center ensemble samples can be used for magnetic field detection. A diamond NV center ensemble sample, which contains multiple NV centers, offers higher detection sensitivity compared to monochromatic center samples.

[0003] When using diamond NV centers for vector magnetic field detection, the four different axes of the diamond NV centers are typically used for detection. Since the projection components of the vector magnetic field along different axes of the NV centers are different, the magnetic field strength along each axis is also different. This is reflected in the optically detected magnetic resonance spectrum as different frequencies and contrasts of the resonance peaks. Furthermore, because the frequencies of each resonance peak are not the same fixed value, microwave frequency sweeping is required to find the corresponding resonance peaks along each axis. However, microwave frequency sweeping usually takes a certain amount of time, which reduces the speed of vector magnetic field detection, resulting in poor real-time performance.

[0004] Therefore, current vector magnetic field detection technology still suffers from poor real-time performance, making it difficult to meet current needs for vector magnetic field detection. Summary of the Invention

[0005] In view of this, embodiments of this application provide a diamond NV color center magnetic detection device and system to solve the problem of poor real-time performance of current vector magnetic field detection technology.

[0006] This application is achieved through the following technical solution: In a first aspect, embodiments of this application provide a magnetic detection device for diamond NV centers. The device includes a first detection module, a second detection module, a third detection module, an optical fiber, a microwave module, and a fluorescence transmission module. The first detection module includes two magnetic flux concentrators, a diamond sample, a first focusing lens, a second focusing lens, a filter, and a photodetector. The two magnetic flux concentrators are respectively placed in contact with the upper and lower surfaces of the diamond sample. The first focusing lens is located on one side of the diamond sample, and the second focusing lens is located on the other side of the diamond NV center sample. The diamond sample is connected to the microwave module. An internal laser emitted from the optical fiber is focused onto the diamond sample by the first focusing lens. The fluorescence generated by the diamond sample under the action of the internal laser and the microwaves provided by the microwave module is collected by the second focusing lens, passes through the filter, and is introduced into the fluorescence transmission module through the photodetector. The second and third detection modules have the same composition as the first detection module, and their assembly directions are perpendicular to each other.

[0007] In conjunction with the first aspect, in some embodiments, the diamond sample has a length and width of less than 1 mm, a thickness of less than 100 μm, a surface roughness of 0.1 nm to 10 nm, and a color center concentration of 0.1 ppm to 200 ppm.

[0008] In conjunction with the first aspect, in some embodiments, the diamond sample has a color center concentration of 3 ppm, a length of 200 μm, a width of 200 μm, a thickness of 50 μm, and a polished crystal facet belonging to the {111} crystal facet family.

[0009] In conjunction with the first aspect, in some embodiments, the diamond sample has a color center concentration of 10 ppm, a length of 300 μm, a width of 300 μm, a thickness of 70 μm, and a polished crystal facet belonging to the {111} crystal facet family.

[0010] In conjunction with the first aspect, in some embodiments, the optical fiber is a 50μm multimode optical fiber, the numerical aperture of the first focusing lens is 0.81, and the diameter of the focused spot of the first focusing lens is 50μm.

[0011] In conjunction with the first aspect, in some embodiments, the optical fiber is a 105μm multimode optical fiber, the numerical aperture of the first focusing lens is 0.81, and the diameter of the focused spot of the first focusing lens is 70μm.

[0012] In conjunction with the first aspect, in some embodiments, the magnetic flux concentrator is frustum-shaped, the upper base diameter of the magnetic flux concentrator is 0.2 mm to 5 mm, the lower base diameter is 1 cm to 10 cm, and the height of the magnetic flux concentrator is the same as the lower base diameter.

[0013] In conjunction with the first aspect, in some embodiments, the magnetic flux concentrator is frustum-shaped, with a lower base diameter of 2.5 cm, a height of 2.5 cm, and an upper base diameter of 0.3 mm.

[0014] Secondly, embodiments of this application provide a diamond NV center magnetic field detection system, the system comprising: a diamond NV center magnetic field detection device as described in any of the first aspects; a microwave unit, including a microwave source and a microwave switch, the microwave switch being used to control the microwave source to provide microwaves to the magnetic field detection device; a laser unit, including a laser, an acousto-optic modulator and a beam splitter, the acousto-optic modulator being used to control the laser to emit a first external laser, the beam splitter being used to split the first external laser into an internal laser and a second external laser; a detection unit, including a lock-in amplifier and a differential photodetector, the lock-in amplifier being connected to the fluorescence transmission module of the magnetic field detection device, the second external laser being transmitted to the lock-in amplifier via the differential photodetector; and a control unit, respectively connected to the microwave unit, the laser unit and the detection unit.

[0015] In conjunction with the second aspect, in some embodiments, the microwave source includes a first microwave source, a second microwave source, and a third microwave source, which are respectively used to provide microwaves to the first detection module, the second detection module, and the third detection module.

[0016] The beneficial effects of the embodiments in this application compared with the prior art are: This application provides a magnetic field detection device and system for diamond NV centers. The detection device includes three mutually perpendicular detection modules, each comprising two magnetic flux concentrators, a diamond sample, a first focusing lens, a second focusing lens, a filter, and a photodetector. The diamond sample is a diamond NV center ensemble. The two magnetic flux concentrators are respectively placed in contact with the upper and lower surfaces of the diamond sample, while the first and second focusing lenses are respectively located on both sides of the diamond sample. The diamond sample is also connected to a microwave module. The first focusing lens focuses a laser beam onto the diamond sample. The fluorescence generated by the diamond sample under the action of the laser and microwave is collected by the second focusing lens, filtered, and then guided to the fluorescence transmission module through the photodetector. This magnetic field detection device includes three sets of independent and mutually perpendicular detection modules. These three sets of detection modules emit different fluorescence signals under the influence of the laser and the microwaves provided by their respective connected microwave modules, and these three sets of fluorescence signals can simultaneously reflect magnetic field information in different directions. This avoids microwave frequency sweeping along different axes of the diamond NV color center, enabling direct and real-time measurement of the vector magnetic field. It solves the problem of poor real-time performance in current vector magnetic field detection technology and realizes real-time detection of the vector magnetic field.

[0017] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this specification. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art 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.

[0019] Figure 1 This is a schematic diagram of the structure of the diamond NV color center magnetic detection device provided in the embodiments of this application; Figure 2 This is a schematic diagram of the target detection module provided in an embodiment of this application; Figure 3 This is a schematic diagram of the intensity of the fluorescence signal after setting the first focusing lens according to an embodiment of this application; Figure 4 This is a schematic diagram of the fluorescence signal intensity in a comparative embodiment without the first focusing lens; Figure 5 This is a schematic diagram of the structure of a diamond NV color center magnetic detection system provided in one embodiment of this application; Figure 6This is a schematic diagram of the detection sensitivity of a diamond NV color center magnetic detection system provided in an embodiment of this application; Figure 7 This is a schematic diagram of the detection sensitivity of a traditional magnetometer. Detailed Implementation

[0020] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limiting purposes, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details.

[0021] It should be understood that, when used in this application specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, elements, components and / or collections thereof.

[0022] It should also be understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0023] Furthermore, in the description of this application and the appended claims, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0024] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0025] As described in the background section, vector magnetic field detection using diamond NV centers typically involves detecting along the four different axes of the diamond NV centers. This detection method requires microwave frequency sweeping and comprehensive calculations to determine the magnetic field information in different directions, making it impossible to directly obtain the magnetic field information in each direction. This results in poor real-time performance of vector magnetic field detection, failing to meet current testing requirements. Therefore, there is an urgent need for a device and system capable of real-time vector magnetic field detection.

[0026] To address the problems of existing technologies, this application provides a magnetic detection device and system for diamond NV centers. The magnetic detection device for diamond NV centers provided in this embodiment will be described below.

[0027] See Figure 1 The diamond NV color center magnetic detection device 100 may include: a first detection module 110, a second detection module 120, a third detection module 130, an optical fiber 140, a microwave module 150, and a fluorescence transmission module 160.

[0028] The first detection module 110, the second detection module 120, and the third detection module 130 are assembled perpendicularly to each other. A microwave module 150 is connected to each of the three detection modules, providing different modulated microwaves for each module; the modulation type can be FM, AM, or TTL modulation. A fluorescence transmission module 160 is connected to each of the three detection modules and transmits the fluorescence signal emitted by each module. An optical fiber provides an internal laser for each detection module; this internal laser is emitted from an external laser source and transmitted through the optical fiber into the magnetic detection device 100.

[0029] The three sets of detection modules are installed in pairs perpendicularly, forming three axes: X, Y, and Z. By using microwaves provided by the microwave module 150 to control the sensors in the X, Y, and Z directions respectively, magnetic field information in different directions can be detected, thus achieving real-time detection of vector magnetic fields.

[0030] Since the internal structures of the first detection module 110, the second detection module 120, and the third detection module 130 are the same, for ease of description, the following will use the target detection module as an example for specific introduction. That is, the target detection module can be any one of the first detection module 110, the second detection module 120, and the third detection module 130.

[0031] See Figure 2 In this embodiment of the application, the target detection module 200 may include two magnetic flux concentrators, a diamond sample 230, a first focusing lens 240, a second focusing lens 250, a filter 260, and a photodetector 270. The diamond sample 230 may be a diamond NV color center ensemble.

[0032] Currently, the optimal approach for magnetic field detection technology based on diamond NV centers in the field of macroscopic magnetic field detection is to integrate a small-sized magnetic flux concentrator to achieve fT / Hz. 1 / 2It can measure magnetic fields on the order of magnitude while also achieving a large detection bandwidth. Moreover, the smaller the gap between the narrow end faces of the two magnetic flux concentrators, the greater the amplification of the magnetic field.

[0033] To minimize the distance between the two magnetic flux concentrators and increase the amplification of the magnetic field, in this embodiment, the two magnetic flux concentrators can be placed in contact with the upper and lower surfaces of the diamond sample 230, respectively. See also Figure 2 The magnetic flux concentrator 210 is in contact with the upper surface of the diamond sample 230, and the magnetic flux concentrator 220 is in contact with the lower surface of the diamond sample 230. The magnetic flux concentrator 210 and the magnetic flux concentrator 220 are made of the same material and have the same shape.

[0034] In some embodiments, the magnetic flux concentrator can be frustum-shaped, with an upper base diameter of 0.2 mm to 5 mm and a lower base diameter of 1 cm to 10 cm. The height of the magnetic flux concentrator is the same as the diameter of its lower base. The material of the magnetic flux concentrator can be permalloy.

[0035] In one possible implementation, the magnetic flux concentrator can be frustum-shaped, with a lower base diameter of 2.5 cm, a height of 2.5 cm, and an upper base diameter of 0.3 mm.

[0036] In some embodiments, to further improve the magnetic field amplification effect of the magnetic flux concentrator, an ultrathin diamond material can be selected. Specifically, the diamond sample 230 can be a diamond NV color center ensemble sample, the length and width of which are both less than 1 mm, the thickness is less than 100 μm, the surface roughness is 0.1 nm to 10 nm, and the color center concentration is 0.1 ppm to 200 ppm.

[0037] In one possible implementation, the diamond sample 230 can be a diamond NV color center ensemble sample, which can have a color center concentration of 3 ppm, a length of 200 μm, a width of 200 μm, a thickness of 50 μm, and the polished crystal facets of the ensemble sample belong to the {111} crystal facet family.

[0038] In another possible implementation, the diamond sample 230 can be a diamond NV color center ensemble sample, which can have a color center concentration of 10 ppm, a length of 300 μm, a width of 300 μm, a thickness of 70 μm, and the polished crystal facets of the ensemble sample belong to the {111} crystal facet family.

[0039] See Figure 2The first focusing lens 240 is located on one side of the diamond sample 230. The second focusing lens 250 is located on the other side of the diamond sample 230. The diamond sample 230 is also connected to the microwave module 150, that is, the microwave module 150 is connected to each detection module by connecting to the diamond sample of each detection module.

[0040] In order to achieve magnetic field detection, the internal laser emitted from the optical fiber 140 is focused on the diamond sample 230 by the first focusing lens 240. The fluorescence generated by the diamond sample 230 under the action of the internal laser and the microwave provided by the microwave module 150 is collected by the second focusing lens 250, filtered by the filter 260, and introduced into the fluorescence transmission module 160 through the photodetector 270.

[0041] Specifically, the first focusing lens 240 can be disposed between the diamond sample 230 and the laser emission port of the optical fiber 140. The first focusing lens 240 can be a focusing lens that can focus the laser onto the diamond sample 230.

[0042] Specifically, the second focusing lens 250 can be disposed on the side of the diamond sample 230 opposite to the first focusing lens 240, and this second focusing lens 250 can be an aspherical focusing lens. As described above, the diamond sample selected in this application is an ultrathin diamond material. The ultrathin size causes the fluorescence emitted by the diamond NV color center ensemble to be inefficiently collected by the photodetector, thereby reducing the sensitivity of the magnetic field detection. In this embodiment, the second focusing lens 250 can collect the fluorescence excited by the diamond sample 230, improving the fluorescence collection efficiency. See also... Figure 2 The fluorescence collected by the second focusing lens 250 passes through the filter 260 and reaches the photodetector 270. The photodetector converts the fluorescence into a fluorescence signal, which is an electrical signal containing magnetic field information. Finally, the fluorescence signal containing magnetic field information is transmitted to the detection unit outside the detection device 100 through the fluorescence transmission module 160, which can analyze the magnetic field information. Since the three detection modules can collect fluorescence signals from different directions, the signal transmitted by the fluorescence transmission module 160 is a vector signal.

[0043] In one possible implementation, when the diamond sample 230 in the target detection module 200 has a thickness of 50 μm, a length of 200 μm, and a width of 200 μm, the aforementioned optical fiber 140 can be a 50 μm multimode optical fiber, the numerical aperture of the first focusing mirror 240 can be 0.81, and the diameter of the focused spot of the first focusing mirror is 50 μm. In this case, the internal laser emitted through the optical fiber 140 is precisely focused on the diamond sample 230 without overflowing. The wavelength of this internal laser can be 532 nm.

[0044] In another possible implementation, when the diamond sample 230 in the target detection module 200 has a thickness of 70 μm, a length of 300 μm, and a width of 300 μm, the aforementioned optical fiber 140 can be a 105 μm multimode optical fiber, the numerical aperture of the first focusing mirror 240 can be 0.81, and the diameter of the focused spot of the first focusing mirror is 70 μm. In this way, the internal laser emitted through the optical fiber 140 is precisely focused onto the diamond sample 230.

[0045] Figure 3 This is a schematic diagram illustrating the intensity of the fluorescence signal when using a first focusing lens, according to an embodiment of this application. Figure 3 As shown, the internal laser emitted from the optical fiber is focused onto the diamond sample by the first focusing lens, and the minimum intensity of the excited fluorescence signal is 639 μV. Figure 4 In the process, while maintaining other experimental conditions and Figure 3 Under the same experimental conditions in the examples, when the internal laser emitted from the optical fiber directly strikes the diamond sample, the maximum intensity of the excited fluorescence signal is 15 μV. It is evident that with the first focusing lens, the intensity of the fluorescence signal is significantly greater than that when the laser is transmitted solely through the optical fiber.

[0046] In this embodiment, a first focusing lens is provided near the emission port of the internal laser, which can improve the excitation efficiency of the internal laser on the diamond NV color center and obtain a higher intensity fluorescence signal.

[0047] In some embodiments, the numerical aperture of the second focusing lens 250 can be 0.9, the filter 260 can be a 637nm filter, and the photodetector 270 can be a Si-based avalanche photodetector.

[0048] In some embodiments, the diamond NV color center magnetic detection device 100 may further include a package housing, and the first detection module 110, the second detection module 120, the third detection module 130, the optical fiber 140, the microwave module 150 and the fluorescence transmission module 160 are all integrated inside the package housing.

[0049] This application provides a diamond NV center magnetic field detection device, comprising three mutually perpendicular detection modules, an optical fiber, a microwave module, and a fluorescence transmission module. Each detection module includes two magnetic flux concentrators, a diamond sample, a first focusing lens, a second focusing lens, a filter, and a photodetector. The diamond sample is an NV center ensemble. The two magnetic flux concentrators are placed in contact with the upper and lower surfaces of the diamond sample, respectively. The first and second focusing lenses are respectively located on both sides of the diamond sample, and the diamond sample is connected to the microwave module. An internal laser in the optical fiber is focused onto the diamond sample by the first focusing lens. The fluorescence generated by the diamond sample under the action of the internal laser and the microwave provided by the microwave module is collected by the second focusing lens, filtered, and then guided into the fluorescence transmission module through the photodetector. Since the diamond sample in each detection module is connected to the microwave module, the three independent detection modules can detect magnetic field information in different directions, thereby realizing real-time detection of vector magnetic fields. This solves the problem of poor real-time performance in current vector magnetic field detection technologies.

[0050] This application also provides a magnetic detection system for diamond NV color centers (NV centers). See [link to relevant documentation]. Figure 5 The magnetic detection system 500 includes: the aforementioned diamond NV color center magnetic detection device 100, a microwave unit 510, a laser unit 520, a detection unit 530, and a control unit 540. The control unit 540 is connected to the microwave unit 510, the laser unit 520, and the detection unit 530, respectively.

[0051] In some embodiments, the control unit 540 may be a device such as a desktop computer, laptop computer, or tablet computer.

[0052] The microwave unit 510 may include a microwave source and a microwave switch. The microwave switch is used to control the microwave source to provide microwaves to the magnetic detection device 100.

[0053] In some embodiments, the microwave source may include a first microwave source, a second microwave source, and a third microwave source, which are used to provide microwaves to the first detection module, the second detection module, and the third detection module in the magnetic detection device 100, respectively.

[0054] The microwaves emitted by the three microwave sources described above are modulated microwaves, and the modulation type can be any of FM, AM, and TTL. Specifically, the microwave frequency of the first microwave source can be set at the maximum slope of the ODMR (Optically Detected Magnetic Resonance) resonance point corresponding to the X-axis, the microwave frequency of the second microwave source can be set at the maximum slope of the ODMR resonance point corresponding to the Y-axis, and the microwave frequency of the third microwave source can be set at the maximum slope of the ODMR resonance point corresponding to the Z-axis. By directly setting the first, second, and third microwave sources as point-frequency microwaves, microwave frequency sweeping is avoided, enabling real-time detection of external magnetic fields.

[0055] In some embodiments, the microwave unit 510 may further include a first pulse generator. The pulse generator can receive instructions from the control unit 540, which can control the pulse generator to emit pulse signals, and the pulse signals can control the microwave switch to turn on or off.

[0056] The laser unit 520 may include a laser, an acousto-optic modulator, and a beam splitter. The acousto-optic modulator controls the laser to emit a first external laser, and the beam splitter splits the first external laser into an internal laser and a second external laser. The split internal laser is transmitted via a transmission line to the magnetic detection device 100 to excite the diamond NV color centers to emit fluorescence. The second external laser can be detected by a differential photodetector in the detection unit 530. The laser's on / off state is controlled by the control unit 540.

[0057] In one possible implementation, the laser parameters can be 532nm-1W, meaning it emits 532nm laser light with a power of 1W. In another possible implementation, the laser parameters can be 532nm-3W.

[0058] The detection unit 530 may include a lock-in amplifier and a differential photodetector. The lock-in amplifier is connected to the fluorescence transmission module of the magnetic field detection device 100. The second external laser is transmitted to the lock-in amplifier via the differential photodetector. After being detected by the differential photodetector, the second external laser can be transmitted to the lock-in amplifier as a differential signal to eliminate laser noise. Simultaneously, the fluorescence transmission module transmits the fluorescence signals containing vector magnetic field information collected by the three target detection modules to the lock-in amplifier. Figure 5 The diamond NV color center magnetic detection device 100 shown in the diagram transmits a vector signal to a lock-in amplifier.

[0059] In some embodiments, the detection unit 530 may further include a second pulse generator connected to a lock-in amplifier, and the second pulse generator is connected to a control unit 540. The control unit 540 can control the second pulse generator to generate an external reference signal, which is fed into the lock-in amplifier as its reference signal. In other embodiments, the reference signal used by the lock-in amplifier may also be an internal reference signal of the instrument.

[0060] In this embodiment, the diamond NV color center magnetic field detection device 100 described above, combined with a lock-in amplifier, can achieve a magnetic field detection bandwidth of DC-100kHz.

[0061] Figure 6 This is a schematic diagram illustrating the detection sensitivity of a diamond NV center magnetic field detection system according to an embodiment of this application. In this embodiment, when using the aforementioned diamond NV center magnetic field detection system for vector magnetic field detection, the sensitivity can reach 0.28 pT / Hz. 1 / 2 That is, 280 fT / Hz 1 / 2 . Figure 7 The detection sensitivity of a conventional magnetometer, which utilizes the fluorescence directly emitted by the diamond sample for measurement, is shown. The sensitivity is 200 pT / Hz. 1 / 2 By comparison, the detection sensitivity of the diamond NV color center magnetic detection system provided in this application embodiment is nearly a thousand times higher than that of a traditional magnetometer.

[0062] This application provides a magnetic field detection system for diamond NV centers, including the aforementioned diamond NV center magnetic field detection device, a microwave unit, a laser unit, a detection unit, and a control unit. The microwave unit is connected to the magnetic field detection device and provides modulated microwaves; the laser unit is connected to the magnetic field detection device and provides internal laser light; the detection unit is also connected to the magnetic field detection device and can detect the fluorescence signal collected by the magnetic field detection device. This system has a simple structure, can achieve real-time detection of vector magnetic fields, and simultaneously achieves detection at pT / Hz. 1 / 2 The following sensitivity vector magnetic field detection effectively solves the problem of poor real-time performance in current vector magnetic field detection technology.

[0063] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0064] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A magnetic detection device for diamond NV color centers, characterized in that, It includes a first detection module, a second detection module, a third detection module, an optical fiber, a microwave module, and a fluorescence transmission module. The assembly directions of the first detection module, the second detection module, and the third detection module are perpendicular to each other. The target detection module includes two magnetic flux concentrators, a diamond sample, a first focusing lens, a second focusing lens, a filter, and a photodetector. The target detection module can be any one of the first detection module, the second detection module, or the third detection module. The diamond sample is a diamond NV color center ensemble. The two magnetic flux concentrators are respectively placed in contact with the upper and lower surfaces of the diamond sample. The first focusing lens is located on one side of the diamond sample, and the second focusing lens is located on the other side of the diamond sample. The diamond sample is connected to the microwave module. The internal laser emitted from the optical fiber is focused onto the diamond sample by the first focusing lens. The fluorescence generated by the diamond sample under the action of the internal laser and the microwave provided by the microwave module is collected by the second focusing lens, passes through the filter, and is introduced into the fluorescence transmission module through the photodetector.

2. The diamond NV color center magnetic detection device as described in claim 1, characterized in that, The diamond sample has a length and width of less than 1 mm, a thickness of less than 100 μm, a surface roughness of 0.1 nm to 10 nm, and a color center concentration of 0.1 ppm to 200 ppm.

3. The diamond NV color center magnetic detection device as described in claim 2, characterized in that, The diamond sample had a color center concentration of 3 ppm, a length of 200 μm, a width of 200 μm, a thickness of 50 μm, and a polished crystal facet belonging to the {111} crystal facet family.

4. The diamond NV color center magnetic detection device as described in claim 2, characterized in that, The diamond sample had a color center concentration of 10 ppm, a length of 300 μm, a width of 300 μm, a thickness of 70 μm, and a polished crystal facet belonging to the {111} crystal facet family.

5. The diamond NV color center magnetic detection device as described in claim 3, characterized in that, The optical fiber is a 50μm multimode fiber, the numerical aperture of the first focusing lens is 0.81, and the diameter of the focused spot of the first focusing lens is 50μm.

6. The diamond NV color center magnetic detection device as described in claim 4, characterized in that, The optical fiber is a 105μm multimode fiber, the numerical aperture of the first focusing lens is 0.81, and the diameter of the focused spot of the first focusing lens is 70μm.

7. The diamond NV color center magnetic detection device according to any one of claims 1 to 6, characterized in that, The magnetic flux concentrator is frustum-shaped, with an upper base diameter of 0.2 mm to 5 mm and a lower base diameter of 1 cm to 10 cm. The height of the magnetic flux concentrator is the same as the lower base diameter.

8. The diamond NV color center magnetic detection device as described in claim 7, characterized in that, The magnetic flux concentrator is frustum-shaped, with a bottom diameter of 2.5cm, a height of 2.5cm, and an top diameter of 0.3mm.

9. A magnetic detection system for diamond NV color centers, characterized in that, include: The diamond NV color center magnetic detection device as described in any one of claims 1 to 8; A microwave unit includes a microwave source and a microwave switch, wherein the microwave switch is used to control the microwave source to provide microwaves to the magnetic detection device. A laser unit includes a laser, an acousto-optic modulator, and a beam splitter. The acousto-optic modulator is used to control the laser to emit a first external laser, and the beam splitter is used to split the first external laser into an internal laser and a second external laser. The detection unit includes a lock-in amplifier and a differential photodetector. The lock-in amplifier is connected to the fluorescence transmission module of the magnetic detection device. The second external laser is transmitted to the lock-in amplifier through the differential photodetector. The control unit is connected to the microwave unit, the laser unit, and the detection unit, respectively.

10. The diamond NV color center magnetic detection system as described in claim 9, characterized in that, The microwave source includes a first microwave source, a second microwave source, and a third microwave source, which are used to provide microwaves to the first detection module, the second detection module, and the third detection module, respectively.

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