Diamond NV color center sensor probe based on coupling of side illumination type light path and planar antenna and magnetic field measurement method

Abstract

The invention relates to a diamond NV color center sensor probe based on coupling of a side illumination type light path and a planar antenna and a magnetic field measurement method. Comprising a base, a diamond NV color center assembly, a laser assembly, a collection assembly and a microwave antenna assembly. The laser assembly, the microwave antenna assembly and the diamond NV color center assembly are arranged on the base; the collecting assembly is installed on the side, opposite to the base, of the diamond NV color center assembly. The microwave antenna assembly is mounted between the diamond NV color center assembly and the base; the laser assembly is used for emitting laser signals to the side face, perpendicular to the base, of the diamond NV color center assembly; the diamond NV color center assembly is used for exciting a fluorescence signal based on the laser signal; the microwave antenna assembly is used for generating a microwave magnetic field; and the collection assembly is used for receiving the fluorescence signal, converting the fluorescence signal into an electric signal, and calculating a magnetic field signal of the to-be-measured magnetic field based on the electric signal. According to the sensor probe, the signal-to-noise ratio of the sensor based on the diamond NV color center can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of quantum precision measurement, in particular to a diamond NV color center sensor probe based on side-illumination optical path and planar antenna coupling and a magnetic field measurement method. BACKGROUND

[0002] The magnetic field measurement sensor probe based on diamond nitrogen-vacancy (NV) color center has the characteristics of high sensitivity and high stability, and has great potential.

[0003] In related technologies, the sensor probe based on NV color center is mostly integrated with a vertical optical path (top-illumination type), that is, the excitation laser and the fluorescence collection share one optical path, that is, the laser beam is vertically incident from the main surface (usually the top surface) of the diamond, and the fluorescence emitted by the NV color center after excitation is also emitted from the same surface. The fluorescence signal emitted by the NV color center is very weak and radiates to a 4π spatial angle, and the design of the shared optical path causes a large amount of fluorescence signal to be unable to be effectively collected, directly causing the signal-to-noise ratio of the final detection signal to be poor.

[0004] Therefore, how to improve the signal-to-noise ratio of the sensor based on the diamond NV color center has become a technical problem to be solved. SUMMARY

[0005] Therefore, it is necessary to provide a diamond NV color center sensor probe based on side-illumination optical path and planar antenna coupling and a magnetic field measurement method in view of the above technical problems.

[0006] In a first aspect, the present application provides a sensor probe based on diamond NV color center, comprising:

[0007] a base, a diamond NV color center assembly, a laser assembly, a collection assembly and a microwave antenna assembly; the laser assembly, the microwave antenna assembly and the diamond NV color center assembly are arranged on the base; the collection assembly is installed on the side of the diamond NV color center assembly opposite to the base; and the microwave antenna assembly is installed between the diamond NV color center assembly and the base;

[0008] the laser assembly is configured to emit a laser signal to the side surface of the diamond NV color center assembly perpendicular to the base;

[0009] the diamond NV color center assembly is configured to excite a fluorescence signal based on the laser signal;

[0010] the microwave antenna assembly is configured to generate a microwave magnetic field, and a region in the microwave magnetic field with a signal greater than a preset signal threshold is coupled with a region inside the diamond NV color center assembly excited by the laser signal;

[0011] The collection assembly is configured to receive the fluorescent signal and convert the fluorescent signal into an electrical signal, and the controller connected to the sensor probe is configured to calculate a magnetic field signal of the magnetic field to be measured based on the electrical signal.

[0012] In one of the embodiments, the sensor probe further comprises a laser alignment assembly integrated with the laser assembly, and the laser alignment assembly comprises an adjusting unit.

[0013] The laser alignment assembly is configured to adjust the laser assembly based on the adjusting unit, so that the laser signal emitted by the laser assembly is coupled with the region in the microwave magnetic field where the signal is greater than the preset signal threshold.

[0014] In one of the embodiments, the collection assembly comprises a fluorescent collection seat and a photodiode.

[0015] The fluorescent collection seat is configured to collect the fluorescent signal emitted by the diamond NV color center assembly from the side opposite to the base and focus all the fluorescent signals at a preset focus point.

[0016] The photodiode is arranged at the focus point and configured to convert the fluorescent signal at the focus point into an electrical signal.

[0017] In one of the embodiments, the sensor probe further comprises a biasing magnet fixed on the base and arranged between the diamond NV color center assembly and the base.

[0018] The biasing magnet is configured to generate a biasing magnetic field in the region where the diamond NV color center assembly is located.

[0019] In one of the embodiments, the sensor probe further comprises a temperature sensor and a temperature control assembly, both of which are integrated with the base.

[0020] The temperature sensor is configured to obtain a temperature value of the region where the diamond NV color center assembly is located and send the temperature value to the temperature control assembly.

[0021] The temperature control assembly is connected to the controller and configured to perform temperature control based on the temperature value, so that the temperature of the region where the diamond NV color center assembly is located is maintained within a preset temperature range.

[0022] In a second aspect, the application further provides a magnetic field measurement method based on a diamond NV color center sensor probe, which is applied to a controller connected to the sensor probe, and the method comprises the following steps:

[0023] The laser assembly is turned on and emits a laser signal to the side of the diamond NV color center assembly perpendicular to the base, and the diamond NV color center assembly emits a fluorescent signal based on the laser signal;

[0024] The microwave antenna assembly generates a microwave magnetic field, and a region in the microwave magnetic field where a signal is greater than a preset signal threshold is coupled with a region inside the diamond NV color center assembly excited by the laser signal;

[0025] The fluorescence signal is collected by the collection assembly arranged on the side of the diamond NV color center assembly opposite the base, and the fluorescence signal is converted into an electrical signal;

[0026] The magnetic field signal of the magnetic field to be measured in which the sensor probe is located is calculated according to the electrical signal; the laser assembly, the microwave antenna assembly, and the diamond NV color center assembly are arranged on the base, and the microwave antenna assembly is installed between the diamond NV color center assembly and the base.

[0027] In one of the embodiments, before the laser assembly is controlled to be turned on and the laser signal is emitted to the side of the diamond NV color center assembly, the method further comprises:

[0028] The temperature value of the region in which the diamond NV color center assembly is located is collected based on the temperature sensor arranged on the base, and the temperature value is fed back to the temperature control assembly arranged on the base;

[0029] The temperature of the region in which the diamond NV color center assembly is located is regulated by the temperature control assembly, so that the temperature of the region in which the diamond NV color center assembly is located is maintained within a preset temperature range.

[0030] In one of the embodiments, the magnetic field signal of the magnetic field to be measured in which the sensor probe is located is calculated according to the electrical signal, comprising:

[0031] Under the action of the magnetic field to be measured, the measured resonance valley of the sensor probe is calculated based on a preset time interval;

[0032] The magnetic field signal of the magnetic field to be measured is calculated according to the drift result of the measured resonance valley.

[0033] In one of the embodiments, the measured resonance valley of the sensor probe is calculated, comprising:

[0034] The microwave antenna assembly generates a sweep microwave signal, and the pre-calculated electrical signal corresponding to the diamond NV color center assembly is obtained through the collection assembly;

[0035] An optical detection magnetic resonance spectrum line is generated according to the pre-calculated electrical signal, and a plurality of initial resonance valleys are determined according to the optical detection magnetic resonance spectrum line;

[0036] The center frequency of each initial resonance valley is determined by scanning at a preset frequency in the range of each initial resonance valley, and the measured resonance valley is obtained.

[0037] In a third aspect, the application also provides a magnetic field measurement device based on a diamond NV color center sensor probe, comprising:

[0038] The starting module is configured to control the laser assembly to start and emit a laser signal to a side of the diamond NV color center assembly perpendicular to the base, and the diamond NV color center assembly is configured to emit a fluorescence signal based on the laser signal;

[0039] The control module is configured to control the microwave antenna assembly to generate a microwave magnetic field, and a region in the microwave magnetic field with a signal greater than a preset signal threshold is coupled with a region inside the diamond NV color center assembly excited by the laser signal;

[0040] The acquisition module is configured to acquire the fluorescence signal through the collection assembly arranged on the side of the diamond NV color center assembly opposite to the base, and convert the fluorescence signal into an electrical signal;

[0041] The generation module is configured to calculate a magnetic field signal of a to-be-measured magnetic field in which the sensor probe is located according to the electrical signal; the laser assembly, the microwave antenna assembly and the diamond NV color center assembly are arranged on the base, and the microwave antenna assembly is installed between the diamond NV color center assembly and the base.

[0042] The above-mentioned diamond NV color center sensor probe and the magnetic field measurement method based on the side-illumination type optical path and the planar antenna coupling, the probe comprises a base, a diamond NV color center assembly, a laser assembly, a collection assembly and a microwave antenna assembly; the laser assembly, the microwave antenna assembly and the diamond NV color center assembly are arranged on the base; the collection assembly is installed on the side of the diamond NV color center assembly opposite to the base; the microwave antenna assembly is installed between the diamond NV color center assembly and the base; the laser assembly is configured to emit a laser signal to a side of the diamond NV color center assembly perpendicular to the base; the diamond NV color center assembly is configured to emit a fluorescence signal based on the laser signal; the microwave antenna assembly is configured to generate a microwave magnetic field, and a region in the microwave magnetic field with a signal greater than a preset signal threshold is coupled with a region inside the diamond NV color center assembly excited by the laser signal; the collection assembly is configured to receive the fluorescence signal and convert the fluorescence signal into an electrical signal, wherein a controller connected with the sensor probe is configured to calculate a magnetic field signal of a to-be-measured magnetic field in which the sensor probe is located based on the electrical signal. The sensor probe in the present application can improve the signal-to-noise ratio of the sensor based on the diamond NV color center. BRIEF DESCRIPTION OF DRAWINGS

[0043] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the related technical solutions, the following will briefly introduce the drawings needed to be used in the embodiments of the present application or the related technical solutions. Obviously, the drawings in the following description are only some embodiments of the present application, and other related drawings can be obtained by those skilled in the art without any creative effort.

[0044] Figure 1A structural schematic diagram of a sensor probe in an embodiment;

[0045] Figure 2 A structural schematic diagram of a sensor probe in another embodiment;

[0046] Figure 3 A flowchart of a magnetic field measurement method in an embodiment;

[0047] Figure 4 A flowchart of calculating a to-be-measured resonance valley in an embodiment;

[0048] Figure 5 A structural block diagram of a magnetic field measurement device in an embodiment. DETAILED DESCRIPTION

[0049] In order to make the purposes, technical solutions and advantages of the present application clearer, the present application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and not to limit the present application.

[0050] The technical background of the present application is described below.

[0051] In a related scheme, there is an integrated sensor probe for high-sensitivity magnetic field measurement based on a diamond nitrogen-vacancy (NV) color center. Due to the high sensitivity and high stability of the diamond NV color center, it has great potential in the fields of power current monitoring and biological magnetic field detection. Its working principle relies on the excitation and spin polarization of the NV color center by laser and the resonance manipulation of the spin state of the NV color center by a microwave field. In related technologies, the integrated NV color center sensor probe adopts a vertical optical path (top illumination type). In this design, the excitation laser and the fluorescence collection share one optical path. The laser beam is vertically incident from the main surface (usually the top surface) of the diamond. The fluorescence emitted by the excited NV color center is also emitted from the same surface. In order to separate the excitation light and the fluorescence, a light splitting element (such as a dichroic mirror) must be integrated in the optical path. Therefore, the laser, the dichroic mirror, the focusing lens, the diamond, and the photodetector need to be complexly optically aligned and integrated along the same axis. This structure faces inherent physical bottlenecks when pursuing extreme integration and signal-to-noise ratio.

[0052] Further, the design of sharing the optical path severely limits the size and numerical aperture (NA) of the fluorescence collection optical device. The fluorescence signal emitted by the NV color center is very weak and is radiated to a 4π spatial angle. This structural limitation results in a large amount of fluorescence signal that cannot be effectively collected, directly causing poor final signal-to-noise ratio (SNR) and limiting the sensitivity of the sensor.

[0053] Moreover, the vertical light path requires multiple discrete optical elements such as dichroic mirrors, filters, focusing lenses, etc., which not only increases the volume and cost of the probe, but also makes the assembly and alignment process very complex and highly precise. In addition, the existing technology mostly adopts a fixed assembly method, which cannot compensate for the machining tolerance of components and the cumulative error introduced during the assembly process, resulting in large performance dispersion and poor consistency of mass-produced products.

[0054] In summary, the above description illustrates the main problems existing in the related art: the common light path design used in the related art results in a large amount of fluorescent signals that cannot be effectively collected, directly causing the signal-to-noise ratio of the final detection signal to be poor.

[0055] Therefore, based on the above, the embodiments of the present application provide a diamond NV color center-based sensor probe: the probe includes a base, a diamond NV color center assembly, a laser assembly, a collection assembly, and a microwave antenna assembly; the laser assembly, the microwave antenna assembly, and the diamond NV color center assembly are all arranged on the base; the collection assembly is installed on the side of the diamond NV color center assembly opposite the base; and the microwave antenna assembly is installed between the diamond NV color center assembly and the base; the laser assembly is configured to emit a laser signal to the side of the diamond NV color center assembly perpendicular to the base; the diamond NV color center assembly is configured to excite a fluorescent signal based on the laser signal; the microwave antenna assembly is configured to generate a microwave magnetic field, and the region in the microwave magnetic field with a signal greater than a preset signal threshold is coupled with the region inside the diamond NV color center assembly excited by the laser signal; and the collection assembly is configured to receive the fluorescent signal and convert the fluorescent signal into an electrical signal, wherein a controller connected to the sensor probe is configured to calculate a magnetic field signal of a to-be-measured magnetic field in which the sensor probe is located based on the electrical signal. Through the scheme in the present application, the incident and outgoing light paths are separated, and the collection assembly is arranged in the direction of the fluorescent light emission, which can maximize the solid angle of the fluorescent light collection, and the collection efficiency can be improved by more than one order of magnitude compared with the traditional scheme, thereby improving the signal-to-noise ratio of the final detected magnetic field signal and optimizing the sensitivity of the sensor. For details, please refer to the following embodiment description:

[0056] In one exemplary embodiment, as shown in Figure 1 FIG. 1, a diamond NV color center-based sensor probe is provided, which includes a base 13, a diamond NV color center assembly 12, a laser assembly 11, a collection assembly (not shown in the figure), and a microwave antenna assembly (not shown in the figure); the laser assembly 11, the microwave antenna assembly, and the diamond NV color center assembly 12 are all arranged on the base 13; the collection assembly is installed on the side of the diamond NV color center assembly 12 opposite the base 13; and the microwave antenna assembly is installed between the diamond NV color center assembly 12 and the base 13.

[0057] The embodiment of the application provides a sensor probe based on a diamond NV color center, wherein specifically, the laser assembly 11, the microwave antenna assembly and the diamond NV color center assembly 12 are arranged on the base 13, the microwave antenna assembly is close to the diamond NV color center assembly 12 and is arranged directly below the diamond NV color center assembly 12, the positions between the laser assembly 11 and the diamond NV color center assembly 12 are at the same height, so that the laser emitted by the laser assembly 11 can irradiate the preset position on the diamond NV color center assembly 12, and the sensor probe in the application can include one laser assembly 11 or two laser assemblies 11, if the two laser assemblies 11 are included, the laser incidence mode of bilateral incidence can be adopted, that is, the two laser assemblies 11 are symmetrically arranged on the opposite sides of the diamond NV color center assembly 12, and the laser incident to the diamond NV color center assembly 12 is in the same straight line, so that the uniformity of the excitation area in the diamond can be further optimized. In actual application, the microwave antenna assembly is connected to the microwave antenna interface arranged at the edge of the base 13 through a wire, so that the preset microwave signal can be input to the microwave antenna assembly, wherein the base 13 can be a PCB.

[0058] The laser assembly 11 is used for emitting a laser signal to the side surface of the diamond NV color center assembly 12 perpendicular to the base 13.

[0059] The diamond NV color center assembly 12 is used for exciting a fluorescence signal based on the laser signal.

[0060] The microwave antenna assembly is used for generating a microwave magnetic field, and a region with a signal greater than a preset signal threshold in the microwave magnetic field is coupled with an excitation region of the diamond NV color center assembly 12 by the laser signal.

[0061] The collection assembly is used for receiving the fluorescence signal and converting the fluorescence signal into an electric signal, wherein a controller connected with the sensor probe is used for calculating a magnetic field signal of a to-be-measured magnetic field in which the sensor probe is located based on the electric signal.

[0062] In the embodiment of the present application, the diamond NV color center component 12 is provided with a light shield, and the laser component 11 emits a laser signal to the side of the diamond NV color center component 12, that is, the side of the diamond NV color center component 12 perpendicular to the base 13. Accordingly, it can be understood that at this time, the laser will form an elongated and through diamond NV color center component 12 band-shaped excitation region inside the diamond NV color center component 12. Specifically, the laser is incident from the side (for example, the (1-10) crystal plane) of the diamond wafer, and the fluorescence is emitted from the top (the (111) crystal plane). Further, the diamond NV color center component 12 is excited to emit a fluorescence signal based on the laser signal. It can be understood that according to the physical properties of the diamond NV color center component 12, the fluorescence signal is uniformly emitted in all directions of the 4π spherical space. In the present application, the fluorescence signal emitted in the direction opposite to the base 13 is received by the collection component provided on the side of the diamond NV color center component 12 opposite to the base 13. Specifically, according to the structure shown in the structural diagram, if the plate surface of the base 13 is regarded as the XY plane, then the side opposite to the base 13 is the positive direction of the Z axis, that is, the side perpendicular to the plate surface of the base 13 and upward. This “orthogonal” design completely breaks the limitation of the traditional common optical path. Figure 1

[0063] The above-mentioned microwave antenna component is used to generate a microwave magnetic field according to the microwave signal input from the microwave antenna interface, and the region in which the signal is greater than the preset signal threshold in the magnetic field (that is, the “sweet spot region” of the microwave antenna magnetic field, that is, the optimal performance region) is coupled with the band-shaped region excited by the laser signal inside the diamond NV color center component 12. “Coupling” means that the geometric shape and size of the microwave antenna component are precisely simulated and optimized in the electromagnetic field in advance, so as to realize the spatial distribution of the alternating magnetic field generated by the microwave antenna component, which maximally overlaps the band-shaped region excited by the laser signal inside the diamond NV color center component 12 in volume, and the direction of the alternating magnetic field is strictly perpendicular to the main axis of the diamond NV color center (that is, the <111> crystal direction).

[0064] According to the above-mentioned content, the region in which the signal is greater than the preset signal threshold in the microwave magnetic field is coupled with the region excited by the laser signal inside the diamond NV color center component 12. This “volume” to “volume” coupling can maximize the number of NV color centers participating in spin manipulation, thereby greatly improving the contrast of the electrical signal generated subsequently.

[0065] The above-mentioned microwave antenna component is arranged between the diamond NV color center component 12 and the base 13, and the microwave antenna component is connected by a wire (that is, a straight line above and below the diamond NV color center component 12), and the wire is provided with an interface, and the signal is transmitted to the microwave antenna component through the interface, so that the microwave antenna component generates a corresponding magnetic field. Figure 1

[0066] ​​Furthermore, the aforementioned collection component is positioned on the side opposite to the base 13 of the diamond NV color center component 12. Since this side is undisturbed, the collection component can cover the entire surface of this side, maximizing the solid angle of fluorescence collection and improving collection efficiency by more than an order of magnitude compared to traditional methods. The collection component converts the collected fluorescence signal into an electrical signal, which is connected to a pre-defined controller. This electrical signal is transmitted to the controller, which then calculates the magnetic field signal of the magnetic field to be measured. In summary, the diamond NV color center-based sensor probe of this application only needs to be placed in the magnetic field to be measured to measure it. To obtain optimal sensitivity, its specific sensitive axis can be aligned with the main direction of the magnetic field, but this is not a strict requirement.

[0067] In this embodiment, by decoupling the incident laser and the emitted fluorescence, the fluorescence collection efficiency is improved. Furthermore, the coupling between the microwave antenna assembly and the region inside the diamond NV color center assembly 12 excited by the laser signal can elevate the sensor's fundamental signal-to-noise ratio to a new level. This is because in related technologies, vertically incident lasers are typically focused into a very small spot to increase power density. Therefore, in related technologies, it is difficult to achieve large-scale, high-efficiency coupling between this "point"-shaped excitation region and the microwave field generated by the microwave antenna in space. The reduction in coupling volume means a reduction in the number of NV color centers participating in resonance, which directly reduces the contrast of the detection signal. Therefore, in this application, by emitting a laser signal to the side of the diamond NV color center assembly 12 perpendicular to the base 13, the "point"-shaped spot in the prior art can be changed to a "strip"-shaped excitation region, significantly increasing the coupling volume and thus improving the signal contrast. Furthermore, the sensor probe in this application avoids the complex and space-consuming confocal optical path components such as dichroic mirrors required in traditional solutions, making the entire probe design simpler, more compact, and more robust, thus providing a foundation for achieving a reliable square probe shape.

[0068] In one exemplary embodiment, the sensor probe further includes a laser alignment assembly integrated on the laser assembly; the laser alignment assembly includes an adjustment unit.

[0069] The laser alignment component is used to adjust the laser component based on the adjustment unit, so that the laser signal emitted by the laser component is coupled in the region excited by the laser component in the diamond NV color center component, and in the region of the microwave magnetic field where the signal is greater than a preset signal threshold.

[0070] In this embodiment, the sensor probe further includes a laser alignment component, which is disposed on the laser assembly and includes multiple adjustment units, such as precision mechanical structures (e.g., precision screws, spring preload, etc.). That is, the laser assembly should include the laser alignment component and a miniaturized semiconductor laser. Through this laser alignment component, after the probe is finally assembled, the laser can be finely adjusted from the outside using the adjustment units in four degrees of freedom: X-axis translation (left-right), Y-axis translation (up-down), pitch angle (θ) rotation, and yaw angle (φ) rotation. The reason for setting up the laser alignment component to finely adjust the laser in the laser assembly is to maximize the spatial distribution of the alternating magnetic field generated by the microwave antenna assembly and maximize the volumetric overlap with the strip-shaped region excited by the laser signal inside the diamond NV color center assembly. This ensures that the trajectory, depth, and height of the excited "light strip" inside the diamond NV color center assembly are perfectly aligned with the optimal performance area of ​​the alternating magnetic field generated by the microwave antenna (i.e., the area where the signal in the magnetic field is greater than the preset signal threshold, as mentioned above), thereby compensating for the processing tolerances of the components and the cumulative errors introduced during assembly.

[0071] In practical applications, during the pre-shipment calibration process, the fluorescence intensity output by the APD (Avalanche Photodiode Detector) and the quality of the ODMR (Optically Detected Magnetic Resonance) signal obtained by frequency sweep are monitored in real time. This fine-tuning mechanism is operated until the system performance indicators (such as fluorescence intensity and ODMR contrast) reach the optimal value. Then, it is permanently locked by tightening screws or curing adhesive, thus completing the optimization of the probe.

[0072] The laser alignment component in this application embodiment can be used to align the laser in the laser component with high precision, so that the spatial distribution of the alternating magnetic field generated by the microwave antenna component can be maximized to overlap with the strip-shaped region excited by the laser signal inside the diamond NV color center component in volume, thereby maximizing the number of NV color centers participating in spin manipulation and improving the contrast of the ODMR signal.

[0073] In one exemplary embodiment, the collection component includes a fluorescent collector and a photodiode;

[0074] The fluorescence collector is used to collect the fluorescence signals emitted from the side opposite to the base of the diamond NV color center assembly and focus all the fluorescence signals at a preset focal point.

[0075] A photodiode, located at the focal point, is used to convert the fluorescence signal at the focal point into an electrical signal.

[0076] The present application embodiment specifically provides the structure of the collection component. The collection component is set on the side of the diamond NV color center component opposite to the base, and includes a fluorescence collection seat and a photodiode. The fluorescence collection seat is a miniature reflector that collects all the fluorescence emitted from all directions on the side of the diamond NV color center component opposite to the base and focuses it to the focal point.

[0077] The photodiode can be an avalanche photodiode, which is placed at the focal point and is specifically used to receive the focused fluorescent signal and convert it into an electrical signal.

[0078] In another embodiment, the collecting component may also be a high numerical aperture lens group consisting of multiple lenses, thereby enabling the collection and collimation of fluorescence.

[0079] In one exemplary embodiment, the sensor probe further includes a bias magnet, which is fixed to the base and disposed between the diamond NV color center assembly and the base.

[0080] Bias magnets are used to generate a bias magnetic field in the region where the diamond NV color center component is located.

[0081] In this embodiment, the sensor probe is also provided with a bias magnet. The bias magnet can be a fixed permanent magnet or a small electromagnetic coil integrated on the base. By precisely controlling the current in the coil, the magnitude and direction of the bias magnetic field can be adjusted.

[0082] The bias magnet is positioned on a base beneath the diamond NV color center assembly, a location that ensures the direction of the magnetic field generated by the bias magnet is aligned with that of the diamond. <111> The crystal orientation is strictly parallel. At the same time, its fixed distance from the diamond ensures that the bias magnetic field has good strength and uniformity.

[0083] The bias magnet is used to generate a bias magnetic field in the region where the diamond NV center component is located, thereby causing the NV center energy level to generate initial Zeeman splitting, shifting the operating point out of the zero-field degeneracy region, thus making the signal clearer and more stable, and enabling more accurate and sensitive detection of the magnetic field to be measured.

[0084] In one exemplary embodiment, such as Figure 2 As shown, the sensor probe also includes a temperature sensor 14 and a temperature control component 15, both of which are integrated on the base.

[0085] Temperature sensor 14 is used to acquire the temperature value of the area where the diamond NV color center component is located and send the temperature value to temperature control component 15;

[0086] Temperature control component 15, connected to the controller, is used to regulate the temperature based on the temperature value so that the temperature of the area where the diamond NV color center component is located is kept within a preset temperature range.

[0087] In this embodiment, a temperature sensor 14 and a temperature control component 15 are also included. The temperature sensor 14 can be a negative temperature coefficient thermistor. The temperature sensor 14 is used to monitor the temperature of the area where the diamond is located in real time and feed the temperature signal back to the temperature control component 15. Correspondingly, the temperature control component 15 can be a thermoelectric cooler, also known as a Peltier element, which is a semiconductor active temperature control device. The temperature control component 15 regulates the temperature of the area where the diamond NV color center component is located based on the temperature value fed back by the temperature sensor 14, so that the temperature of the area where the diamond NV color center component is located is maintained within a preset temperature range. A closed-loop temperature control system is formed by the temperature sensor 14 and the temperature control component 15, realizing precise temperature control of the diamond NV color center component.

[0088] This application also provides a preferred embodiment of a sensor probe based on diamond NV color centers.

[0089] The sensor probe includes a base (which can be a circuit board base, i.e., a PCB), a diamond NV color center assembly, a laser assembly, a collection assembly, a temperature sensor, a temperature control assembly, and a microwave antenna assembly fixed on the base. The laser assembly also includes a laser alignment component. All external interfaces (data / power supply, microwave) are located at the edge of the circuit board for easy integration. For subsequent calculations, the sensor probe is connected to a pre-defined controller. Specifically, the controller is connected to the microwave source in the microwave antenna assembly to send commands to the microwave source and control the microwave antenna to scan within a preset frequency range. The controller is also connected to a photodiode in the collection assembly to read the electrical signal converted by the photodiode for subsequent calculations. Furthermore, the controller is connected to the laser assembly and the temperature control assembly to control their switching and parameter settings, ensuring the sensor probe operates in a stable state.

[0090] The aforementioned diamond NV color center assembly, laser assembly, temperature sensor, temperature control assembly, and microwave antenna assembly are all mounted on the base. The microwave antenna is positioned below the diamond NV color center assembly and is connected to a wire that connects to an interface. This interface receives commands from the controller to control the microwave antenna to scan within a preset frequency range. A bias magnet is also located below the diamond NV color center assembly. The collecting assembly is mounted on the side of the diamond NV color center assembly opposite the base. The base also houses a power supply to power the entire sensor probe. It is crucial that the laser assembly and the diamond NV color center assembly be at the same height so that the laser emitted by the laser assembly can penetrate and excite the diamond NV color center assembly. To ensure temperature stability at the diamond NV color center assembly, the temperature sensor needs to be placed as close as possible to the assembly to obtain accurate temperature readings.

[0091] This application also provides a magnetic field measurement method based on a diamond NV color center sensor probe, such as... Figure 3 As shown, the method, applied to a controller connected to a sensor probe, includes:

[0092] Step S310: Control the laser component to turn on and emit a laser signal to the side of the diamond NV color center component that is perpendicular to the base, wherein the diamond NV color center component excites a fluorescence signal based on the laser signal;

[0093] Step S320: Control the microwave antenna assembly to generate a microwave magnetic field. The region in the microwave magnetic field where the signal is greater than a preset signal threshold is coupled with the region inside the diamond NV color center assembly that is excited by the laser signal.

[0094] Step S330: The fluorescence signal is collected by the collecting component set on the side of the diamond NV color center component opposite to the base, and the fluorescence signal is converted into an electrical signal.

[0095] Step S340: Calculate the magnetic field signal of the magnetic field to be measured at the sensor probe based on the electrical signal; the laser component, microwave antenna component and diamond NV color center component are all set on the base, and the microwave antenna component is installed between the diamond NV color center component and the base.

[0096] In this embodiment, the controller is independent of the sensor probe but connected to it via both wired and wireless connections. The controller activates the laser assembly, causing it to emit a laser signal towards the side of the diamond NV center assembly perpendicular to the base. The diamond NV center assembly, stimulated by the laser signal, generates a fluorescence signal. The controller also controls a microwave antenna assembly to generate a microwave magnetic field. The region within this magnetic field where the signal exceeds a preset threshold (i.e., the optimal performance region) couples with the region inside the diamond NV center assembly excited by the laser signal, thereby maximizing the number of NV centers participating in spin manipulation. Furthermore, the controller acquires an electrical signal transmitted by a collection assembly located on the side of the diamond NV center assembly opposite the base. This collection assembly first collects the fluorescence signal and converts it into an electrical signal. Finally, the controller calculates the magnetic field signal of the magnetic field to be measured at the sensor probe location based on the electrical signal.

[0097] In one exemplary embodiment, before controlling the laser component to turn on and emitting a laser signal toward the side of the diamond NV color center component, the method further includes:

[0098] The temperature value of the area where the diamond NV color center component is located is collected by the temperature sensor set on the base, and the temperature value is fed back to the temperature control component set on the base.

[0099] The temperature of the area where the diamond NV color center component is located is regulated by a temperature control component to keep the temperature of the area where the diamond NV color center component is located within a preset temperature range.

[0100] In this embodiment, after the probe is powered on, the temperature sensor and temperature control component are activated. First, the temperature sensor collects the temperature value of the area where the diamond NV color center component is located and feeds this value back to the temperature control component. The temperature control component then regulates the temperature of the area where the diamond NV color center component is located based on the temperature value, thereby stabilizing the temperature of this area within a preset temperature range. This prevents the resonance valley of the diamond NV color center component from drifting due to temperature changes during subsequent magnetic field measurements.

[0101] In an exemplary embodiment, the magnetic field signal of the magnetic field to be measured at the location of the sensor probe is calculated based on the electrical signal, including:

[0102] Under the influence of the magnetic field to be measured, the resonance valley of the sensor probe is calculated based on a preset time interval;

[0103] The magnetic field signal of the magnetic field to be measured is calculated based on the drift result of the resonance valley to be measured.

[0104] In one exemplary embodiment, this application takes into account that the magnetic field to be measured is generally a constantly changing magnetic field. Therefore, it is necessary to calculate the target resonance valley of the sensor probe in real time according to a preset time interval, that is, to calculate the position of multiple resonance valleys multiple times according to the time interval, so as to reflect the changes in the target magnetic field in real time. The magnetic field signal of the target magnetic field can be calculated based on the drift result of the target resonance valley.

[0105] Because it is used <111> The crystal orientation of the ensemble NV diamond is such that its ODMR spectrum splits into four identifiable resonance valleys. Understandably, since the magnetic field to be measured changes, the vector or scalar information of the magnetic field to be measured can be deduced from the drift of the resonance valleys. The magnetic field signal can be calculated according to a preset algorithm, and then the current value in the conductor can be calculated according to Ampere's law.

[0106] Furthermore, it is understandable that the changes in the four resonance valleys mainly include synchronous drift and relative changes. Due to factors such as temperature variations, all resonance valleys will move synchronously and in the same direction, which is caused by environmental interference. However, due to changes in the magnetic field being measured, the spacing between the frequencies of the multiple resonance valleys will change. Therefore, the synchronous drift of each resonance valley can be ignored, and only the pattern and magnitude of the relative displacement between each resonance valley can be considered. Thus, by observing the relative changes between the resonance valleys, the true magnetic field value can be accurately deduced. Finally, the calculated magnetic field value is output through the data interface.

[0107] In one exemplary embodiment, such as Figure 4 As shown, the calculation of the resonance valley to be measured by the sensor probe includes:

[0108] Step S410: Control the microwave antenna assembly to generate a swept-frequency microwave signal, and obtain the pre-calculated electrical signal corresponding to the diamond NV color center assembly through the collection assembly.

[0109] In this embodiment, the laser component is activated, emitting green light towards the diamond NV color center component. The green light efficiently excites the color center ensemble of the diamond NV color center component from the side, causing it to emit red fluorescence. Furthermore, the controller inputs a wide-range, fast-sweeping microwave signal to the microwave antenna component via an interface. Consequently, the collection component at the top of the diamond NV color center component continuously converts the fluorescence signal into an electrical signal, namely the aforementioned pre-calculated electrical signal.

[0110] Step S420: Generate optical detection magnetic resonance spectral lines based on the pre-calculated electrical signal, and determine multiple initial resonance valleys based on the optical detection magnetic resonance spectral lines.

[0111] In this embodiment of the application, since the method used is... <111> The ensemble NV diamond with crystal orientation will split into four identifiable resonance valleys, namely the initial resonance valleys, under the combined action of the magnetic field to be measured and the bias magnetic field (the bias magnetic field built into the sensor can produce initial Zeeman splitting of the NV color center energy level, shifting the operating point out of the zero field degeneracy region).

[0112] Step S430: Scan the range of each initial resonance valley at a preset frequency to determine the center frequency of each initial resonance valley and obtain the resonance valley to be measured.

[0113] In this embodiment, the initial resonance valley is a rough location of the resonance valley. This application further employs precision measurement techniques such as lock-in amplification to perform a narrow-range, high-precision frequency (i.e., the preset frequency) scan near each initial resonance valley, thereby accurately determining the center frequency of the four resonance valleys, thus obtaining the accurate resonance valley to be measured.

[0114] This application also provides a preferred embodiment of a magnetic field measurement method based on a diamond NV color center sensor probe, and assumes that the sensor probe is placed with the base at the bottom and components such as the diamond NV color center on top.

[0115] First, the sensor probe is powered on, and the temperature control system is activated. Based on the temperature value fed back by the temperature sensor, the temperature of the region where the diamond NV color center is located is regulated to stabilize it within the preset temperature range. In addition, the bias magnet built into the diamond NV color center component has generated the initial Zeeman split of the NV color center energy level, moving the operating point out of the zero-field degeneracy region.

[0116] The laser assembly then activates, emitting green light that excites the NV color center ensemble within the diamond from the side, causing it to emit red fluorescence. The top collecting assembly continuously measures the fluorescence intensity collected by the fluorescence collector.

[0117] An external controller receives a fast, wide-range swept-frequency microwave signal via a microwave component interface. Because it uses... <111> In ensemble NV diamond with specific crystal orientation, the ODMR spectrum splits into four identifiable resonance valleys under the combined influence of a bias magnetic field and the magnetic field to be measured. This step rapidly obtains the approximate frequency positions of these four valleys.

[0118] Based on the rough position obtained in the previous step, the controller uses precision measurement techniques such as lock-in amplification to perform a narrow-range, high-precision frequency scan near each resonance valley, thereby accurately determining the center frequencies f1, f2, f3, and f4 of the four resonance valleys.

[0119] The positions of these four resonant frequencies will drift together as the magnetic field under test changes. The controller, using a preset physical model and algorithm, accurately derives the vector or scalar information of the external magnetic field based on the changes in these four frequency values. Then, it calculates the current value in the conductor using Ampere's law and other methods.

[0120] Finally, the calculated current / magnetic field values ​​are output through the edge data interface.

[0121] It should be understood that although the steps in the flowcharts of the embodiments described above are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the embodiments described above may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages of other steps.

[0122] Based on the same inventive concept, this application also provides a magnetic field measuring device based on a diamond NV color center sensor probe for implementing the magnetic field measuring method based on the diamond NV color center sensor probe described above. The solution provided by this device is similar to the solution described in the above method; therefore, the specific limitations in one or more magnetic field measuring device embodiments provided below can be found in the limitations of the magnetic field measuring method above, and will not be repeated here.

[0123] In one exemplary embodiment, such as Figure 5 As shown, a magnetic field measuring device is provided, comprising:

[0124] The startup module 51 is used to control the laser component to turn on and emit a laser signal to the side of the diamond NV color center component that is perpendicular to the base. The diamond NV color center component excites a fluorescence signal based on the laser signal.

[0125] Control module 52 is used to control the microwave antenna assembly to generate a microwave magnetic field. The region in the microwave magnetic field where the signal is greater than a preset signal threshold is coupled to the region inside the diamond NV color center assembly that is excited by the laser signal.

[0126] Acquisition module 53 is used to acquire fluorescence signals through a collection component set on the side opposite to the base of the diamond NV color center assembly, and convert the fluorescence signals into electrical signals;

[0127] The generation module 54 is used to calculate the magnetic field signal of the magnetic field to be measured at the sensor probe based on the electrical signal; the laser component, microwave antenna component and diamond NV color center component are all set on the base, and the microwave antenna component is installed between the diamond NV color center component and the base.

[0128] In one exemplary embodiment, a second temperature module and a second adjustment module are also included;

[0129] The second temperature module is used to collect the temperature value of the area where the diamond NV color center component is located based on the temperature sensor set on the base, and to feed the temperature value back to the temperature control component set on the base.

[0130] The second adjustment module is used to regulate the temperature of the area where the diamond NV color center component is located through the temperature control component, so as to keep the temperature of the area where the diamond NV color center component is located within the preset temperature range.

[0131] In one exemplary embodiment, a third computing module and a third generation module are also included;

[0132] The third calculation module is used to calculate the resonance valley of the sensor probe under the action of the magnetic field to be measured based on a preset time interval.

[0133] The third generation module is used to calculate the magnetic field signal of the magnetic field to be measured based on the drift result of the resonance valley to be measured.

[0134] In one exemplary embodiment, it further includes a fourth collection module, a fourth determination module, and a fourth calculation module:

[0135] The fourth collection module is used to control the microwave antenna assembly to generate a swept microwave signal and to acquire the pre-calculated electrical signal corresponding to the diamond NV color center assembly through the collection assembly.

[0136] The fourth determination module is used to generate optical detection magnetic resonance spectral lines based on the pre-calculated electrical signal, and to determine multiple initial resonance valleys based on the optical detection magnetic resonance spectral lines.

[0137] The fourth calculation module is used to scan the range of each initial resonance valley at a preset frequency to determine the center frequency of each initial resonance valley and obtain the resonance valley to be measured.

[0138] The various modules in the aforementioned magnetic field measurement device based on a diamond NV color center sensor probe can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in or independent of the processor in a computer device in hardware form, or stored in the memory of a computer device in software form, so that the processor can call and execute the corresponding operations of each module.

[0139] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile memory and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM). The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, artificial intelligence (AI) processors, etc., and are not limited to these.

[0140] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

[0141] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A diamond NV color center sensor probe based on side-illuminated optical path and planar antenna coupling, characterized in that, The probe includes: a base, a diamond NV color center assembly, a laser assembly, a collecting assembly, and a microwave antenna assembly; the laser assembly, the microwave antenna assembly, and the diamond NV color center assembly are all disposed on the base; the collecting assembly is installed on the side of the diamond NV color center assembly opposite to the base; the microwave antenna assembly is installed between the diamond NV color center assembly and the base; The laser component is used to emit laser signals toward the side of the diamond NV color center component that is perpendicular to the base; The diamond NV color center component is used to excite a fluorescence signal based on the laser signal; The microwave antenna assembly is used to generate a microwave magnetic field, and the region in the microwave magnetic field where the signal is greater than a preset signal threshold is coupled to the region inside the diamond NV color center assembly that is excited by the laser signal. The collection component is used to receive the fluorescence signal and convert the fluorescence signal into an electrical signal, wherein the magnetic field signal of the magnetic field to be measured at the location of the sensor probe is calculated based on the electrical signal by a controller connected to the sensor probe.

2. The sensor probe according to claim 1, characterized in that, The sensor probe also includes a laser alignment component, which is integrated on the laser component; the laser alignment component includes an adjustment unit. The laser alignment component is used to adjust the laser component based on the adjustment unit, so that the region where the laser signal emitted by the laser component is excited in the diamond NV color center component is coupled with the region in the microwave magnetic field where the signal is greater than a preset signal threshold.

3. The sensor probe according to claim 1 or 2, characterized in that, The collection assembly includes a fluorescent collector and a photodiode; The fluorescence collection holder is used to collect the fluorescence signal emitted by the diamond NV color center assembly from the side opposite to the base, and to focus all the fluorescence signals at a preset focal point; The photodiode is disposed at the focal point and is used to convert the fluorescence signal at the focal point into the electrical signal.

4. The sensor probe according to claim 1 or 2, characterized in that, The sensor probe also includes a bias magnet, which is fixed on the base and disposed between the diamond NV color center assembly and the base; The bias magnet is used to generate a bias magnetic field in the region where the diamond NV color center component is located.

5. The sensor probe according to claim 1 or 2, characterized in that, The sensor probe also includes a temperature sensor and a temperature control component, both of which are integrated on the base. The temperature sensor is used to acquire the temperature value of the area where the diamond NV color center component is located, and send the temperature value to the temperature control component; The temperature control component is connected to the controller and is used to regulate the temperature based on the temperature value so that the temperature of the area where the diamond NV color center component is located is maintained within a preset temperature range.

6. A method for measuring the magnetic field of a diamond NV color center sensor probe based on a side-illuminated optical path coupled to a planar antenna, applied to a controller connected to the sensor probe, characterized in that... The method includes: The laser component is controlled to turn on and emits a laser signal to the side of the diamond NV color center component that is perpendicular to the base, wherein the diamond NV color center component excites a fluorescence signal based on the laser signal; A microwave antenna assembly is controlled to generate a microwave magnetic field, and the region in the microwave magnetic field where the signal is greater than a preset signal threshold is coupled to the region inside the diamond NV color center assembly that is excited by the laser signal. The fluorescence signal is collected by a collecting component located on the side of the diamond NV color center assembly opposite to the base, and the fluorescence signal is converted into an electrical signal. The magnetic field signal of the magnetic field to be measured at the location of the sensor probe is calculated based on the electrical signal; the laser component, the microwave antenna component and the diamond NV color center component are all disposed on the base, and the microwave antenna component is installed between the diamond NV color center component and the base.

7. The method according to claim 6, characterized in that, Before the laser component is activated and a laser signal is emitted to the side of the diamond NV color center component, the method further includes: The temperature sensor installed on the base collects the temperature value of the area where the diamond NV color center component is located, and feeds the temperature value back to the temperature control component installed on the base; The temperature control component regulates the temperature of the area where the diamond NV color center component is located, so that the temperature of the area where the diamond NV color center component is located is maintained within a preset temperature range.

8. The method according to claim 6 or 7, characterized in that, The calculation of the magnetic field signal of the magnetic field to be measured at the location of the sensor probe based on the electrical signal includes: Under the influence of the magnetic field to be measured, the resonance valley of the sensor probe is calculated based on a preset time interval; The magnetic field signal of the magnetic field to be measured is calculated based on the drift result of the resonance valley to be measured.

9. The method according to claim 8, characterized in that, The calculation of the resonance valley to be measured by the sensor probe includes: The microwave antenna assembly is controlled to generate a swept microwave signal, and the pre-calculated electrical signal corresponding to the diamond NV color center assembly is obtained through the collection assembly. An optical detection magnetic resonance spectral line is generated based on the pre-calculated electrical signal, and multiple initial resonance valleys are determined based on the optical detection magnetic resonance spectral line. The range of each initial resonance valley is scanned at a preset frequency to determine the center frequency of each initial resonance valley, thus obtaining the resonance valley to be measured.

10. A magnetic field measurement device based on a diamond NV color center sensor probe coupled with a side-illuminated optical path and a planar antenna, characterized in that, The device includes: A startup module is used to control the laser component to turn on and emit a laser signal to the side of the diamond NV color center component that is perpendicular to the base, wherein the diamond NV color center component excites a fluorescence signal based on the laser signal; The control module is used to control the microwave antenna assembly to generate a microwave magnetic field, wherein the region in the microwave magnetic field where the signal is greater than a preset signal threshold is coupled to the region inside the diamond NV color center assembly that is excited by the laser signal. The acquisition module is used to acquire the fluorescence signal through a collection component disposed on the side of the diamond NV color center assembly opposite to the base, and convert the fluorescence signal into an electrical signal; The generation module is used to calculate the magnetic field signal of the magnetic field to be measured at the location of the sensor probe based on the electrical signal; the laser component, the microwave antenna component and the diamond NV color center component are all disposed on the base, and the microwave antenna component is installed between the diamond NV color center component and the base.

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