Diamond nv color center magnetic field measurement system based on data matrix analysis

Abstract

The application discloses a diamond NV color center magnetic field measurement system based on data matrix analysis, which comprises an optical path module, a microwave module, a probe module and a magnetic measurement electronics module; wherein the optical path module mainly comprises a laser source, a half-wave plate, a beam splitter, a lens and a neutral density plate; the microwave module mainly comprises a microwave source, a shield, a power amplifier, a PC and a switch; the probe module mainly comprises a rotating sample holder and a long-wave pass filter; and the magnetic measurement electronics module mainly comprises a photodetector PD, a main amplifier, a filter, a cancellation circuit, a differentiator, an analog-to-digital conversion module ADC, an FPGA module and a digital-to-analog conversion module DAC. The application realizes multi-channel data parallel communication and data matrix analysis under a continuous wave type magnetic measurement mode, so that the speed of the system for magnetic field measurement and the compatibility of external communication can be improved.

Description

Technical Field

[0001] This invention relates to the field of signal acquisition and processing in high-precision instruments, specifically a diamond NV color center magnetic field measurement system based on data matrix analysis. Background Technology

[0002] With the further development of accelerator physics, power systems, and other fields, higher requirements are being placed on the precision of electrical measurements and the reliability of measurement values. The localization and domestic production of key instruments are crucial means to support my country's cutting-edge technology and industrial manufacturing. One of the core technologies indispensable for the localization and domestic production of key instruments is precision magnetic field measurement technology. In related technologies, the measurement of magnetic field strength of diamond NV centers often employs a pulse-type magnetometry method. This process requires pulse control of multiple laser and microwave signals, making the steps complex and difficult to operate. Furthermore, during magnetic field measurement, the NV center emits a red fluorescence signal after being excited by laser polarization, a microwave source, and the magnetic field to be measured. The core step in obtaining magnetic field information is to obtain the microwave source sweep frequency at the moment of minimum fluorescence signal value. If related instruments, such as a spectrum analyzer or a PC, are used, the small size of the additional instruments prevents the full realization of the advantages of the miniaturized and integrated diamond NV center magnetometry system, and it is difficult to interact with different subsequent magnetic signal processing systems / devices. Without related instruments, extracting the microwave frequency is extremely difficult. Summary of the Invention

[0003] The present invention addresses the shortcomings of the existing technology by proposing a diamond NV center magnetic field measurement system based on data matrix analysis. This system aims to achieve multi-channel parallel data communication and data matrix analysis in continuous wave magnetic measurement mode, thereby improving the system's magnetic field measurement speed and external communication compatibility.

[0004] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0005] The present invention provides a diamond NV color center magnetic field measurement system based on data matrix analysis, characterized in that it includes: an optical path module, a microwave module, a probe module, and a magnetometry electronics module;

[0006] The optical path module consists of a first half-wave plate, a beam splitter, a second half-wave plate, and a lens arranged sequentially in front of the laser source; a neutral density plate is arranged on one side of the beam splitter.

[0007] The probe module is disposed in front of the lens and includes: a rotating sample holder and a long-pass filter;

[0008] A diamond NV color center sample under a static magnetic field is placed on the rotating sample holder; a long-pass filter is disposed on the lower surface of the diamond NV color center sample.

[0009] The magnetometry electronics module includes: a first photodetector PD, a second photodetector PD, a first main amplifier, a second main amplifier, a first filter, a second filter, a third filter, a phase cancellation circuit, a differentiator, an analog-to-digital converter (ADC), an FPGA module, and a digital-to-analog converter (DAC).

[0010] The first photodetector PD, the first main amplifier, and the first filter are sequentially arranged in front of the neutral density sheet;

[0011] The second photodetector PD is placed directly below the long-pass filter and is connected in sequence to the second main amplifier and the second filter;

[0012] The outputs of the first and second filters are connected to the input of the cancellation circuit. The output of the cancellation circuit has two signals: one is connected to an oscilloscope, and the other is connected in sequence to a differentiator, a third filter, an analog-to-digital converter (ADC), an FPGA module, and a digital-to-analog converter (DAC).

[0013] The microwave module includes: a microwave source, a shield, a power amplifier, a PC terminal, and a switch;

[0014] The microwave source is connected to the FPGA module via the switch; the switch is also connected to the PC.

[0015] The microwave source is connected in sequence to the shield and the power amplifier; the output terminal of the power amplifier is connected to the diamond NV color center sample.

[0016] The laser source emits a laser of a certain wavelength, which is split into two beams after passing through the first half-wave plate and the beam splitter in sequence. One beam passes through the second half-wave plate and the lens in sequence and then illuminates the diamond NV color center sample.

[0017] Under the control of the PC, the microwave source emits microwave signals, which are transmitted to the diamond NV color center sample after passing through the shield and power amplifier in sequence.

[0018] The diamond NV color center sample emits a fluorescence signal, which is received by the second photodetector PD after passing through the long-pass filter and converted into a second electrical signal. The signal is then transmitted sequentially to the second main amplifier and the second filter. The second filter outputs an undenoised fluorescence signal and inputs it into the phase cancellation circuit.

[0019] Another path of light passes through the neutral density plate, is received by the first photodetector PD, and is converted into a first electrical signal, which is then transmitted sequentially to the first main amplifier and the first filter. The first filter outputs a noise floor signal and inputs it into the phase cancellation circuit.

[0020] After the cancellation circuit processes the undenoised fluorescence signal and the background noise signal, the fluorescence modulation signal is obtained after being processed by the differentiator and the third filter and then transmitted to the analog-to-digital converter module ADC and the FPGA module in sequence.

[0021] The PC sends the microwave frequency of the microwave source to the FPGA module through the switch;

[0022] The FPGA module processes the received fluorescence modulation signal and microwave frequency to obtain the strength B of the static magnetic field. e The data is then transmitted to the digital-to-analog converter (DAC) for processing, and the final simulated magnetic field strength V0 is output.

[0023] The diamond NV color center magnetic field measurement system based on data matrix analysis described in this invention is also characterized in that the FPGA module processes the received fluorescence modulation signal and microwave frequency within one sweep cycle according to the following steps:

[0024] Step 1: If the FPGA module receives the nth fluorescence modulation signal within the range of 0 ± Δ during one working cycle, then set its logic value K. n If it is 0, otherwise, set its logical value K. n K is 1. n The logic value of the nth fluorescence modulation signal is represented; Δ represents the allowable error range.

[0025] Step 2: For the nth and (n+1)th logic values ​​K n K n+1 Perform an OR operation; when the OR operation result is 1, then the nth and (n+1)th fluorescence modulation signals are determined to be valid signals, denoted as V. n and V n+1 and the nth valid signal V n The sweep frequency is denoted as f. n The (n+1)th valid signal V n+1 The sweep frequency is denoted as f. n+1 Otherwise, it is considered an invalid signal.

[0026] Step 3: Collect all valid signals V n and its sweep frequency f n By sequentially integrating, a matrix is ​​obtained.

[0027] Step 4: Divide the matrix A into 2×2 block matrices by column:

[0028] When n is odd, add a column of identical data after the last column of matrix A, denoted as A = (A1 A2 A3…A…).i …A (n+1) / 2 );

[0029] When n is even, it is denoted as A = (A1 A2 A3…A…). i …A n / 2 ); where A i Let A represent the i-th block matrix. (n+1) / 2 Let A represent the (n+1) / 2th block matrix. n / 22 This represents the n / 2th block matrix;

[0030] Step 5: Use equations (1) and (2) to define the block matrix A respectively. i Calculations are performed to obtain matrices M and N;

[0031]

[0032]

[0033] M = (M1 M2 M3…M) i …M n / 2 (3)

[0034] N = (N1 n2 N3 … N) i …N n / 2 (4) In equations (3) and (4), M i Let N represent the i-th block matrix in matrix M. i This represents the i-th block matrix in matrix N;

[0035] Step 6: For the i-th block matrix M i Each element in each column is evaluated. If any element in a column falls within the range of 0 ± Δ, the logical value of the corresponding element is set to 0; otherwise, the logical value of the corresponding element is set to 1, thus obtaining the block matrix M. i Logical value matrix M' i ; and for the i-th logical value matrix M' i Perform an XOR logical operation on each column to obtain the XOR result for each column;

[0036] When the XOR result is 1, the i-th block matrix M is... i The non-zero elements in the corresponding column are used as frequency extraction values, denoted as . And continue to perform judgments and XOR logic operations on other block matrices in matrix M;

[0037] When the XOR result is 0, the logical value matrix M' is determined. i Should both columns be subjected to an XOR logical operation?

[0038] If the logical value matrix M' iIf both columns have been processed, then the other blocks in matrix M are judged and subjected to XOR logical operations.

[0039] If the logical value matrix M' i If the operations on both columns are not fully completed, then the logical value matrix M' i After performing an XOR operation on the next column of elements, the other block matrices in matrix M are then judged and subjected to XOR operations.

[0040] Step 7: Perform judgment and XOR logic operation on the block matrix in matrix N according to step 4, and obtain the frequency extraction value, denoted as .

[0041] Step 8: Within one working cycle, obtain four extraction frequency values ​​according to the process of steps 1-7, sort them in ascending order, and record them as f1, f2, f3, and f4; calculate the intensity B of the static magnetic field (28) using equation (5). e ;

[0042]

[0043] In equation (5), g is the Landé factor, μ B It is the Bohr magneton.

[0044] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0045] 1. This invention acquires fluorescence modulation signal data and microwave frequency data from a microwave source, and uses a magnetometry electronics module to receive and analyze the data to complete the measurement of the magnetic field to be measured. Under continuous wave magnetometry, it realizes multi-channel parallel data communication and data matrix analysis, which improves the system's speed of magnetic field measurement and compatibility with external communication.

[0046] 2. This invention modulates the noise-reduced fluorescence signal using a differentiator in the magnetic measurement electronics module to obtain a modulated fluorescence signal. It converts the sweep frequency corresponding to the minimum point of the fluorescence signal into the sweep frequency corresponding to the zero point of the modulated fluorescence signal, thus omitting the complex data comparison process and simplifying the data processing method.

[0047] 3. This invention proposes a data matrix analysis method: The method involves effectively judging the logical operations of the modulated fluorescence signal, integrating the effective signal and its corresponding frequency information into matrix A, and then performing block division, operations, and logical judgments on matrix A to obtain the required sweep frequency, thereby calculating the external static magnetic field strength. Data matrix analysis can match fluorescence modulation signal information with frequency information, facilitating subsequent extraction of the required frequency information. It is simple to operate and easy to implement. Attached Figure Description

[0048] Figure 1This is a schematic diagram of the structure of the diamond NV color center magnetic field measurement system of the present invention;

[0049] Figure 2 The NV axis distribution diagram of diamond NV color center crystals in Cartesian coordinates;

[0050] Figure 3 The area inside the dashed box is a schematic diagram of the internal unit structure of the FPGA of the magnetic measurement system.

[0051] Figure 4 The image shows the fluorescence signal curve on the oscilloscope when the correction step is completed, where T is the time of one sweep cycle of the microwave source.

[0052] The following components are labeled in the diagram: 1. Laser source; 2. First half-wave plate; 3. Beam splitter; 4. Second half-wave plate; 5. Lens; 6. Neutral density plate; 7. Diamond NV color center sample; 8. Long-pass filter; 9. Second photodetector (PD); 10. First photodetector (PD); 11. First main amplifier; 12. First filter; 13. Second main amplifier; 14. Second filter; 15. Cancellation circuit; 16. Differentiator; 17. Third filter; 18. Analog-to-digital converter (ADC); 19. FPGA module; 20. Digital-to-analog converter (DAC); 21. Switch; 22. PC terminal; 23. Microwave source; 24. Shielder; 25. Power amplifier; 26. Static magnetic field; 27. Oscilloscope. Detailed Implementation

[0053] In this embodiment, a diamond NV color center magnetic field measurement system based on data matrix analysis is described, such as... Figure 1 As shown, it includes: an optical path module, a microwave module, a probe module, and a magnetometry electronics module;

[0054] The optical path module consists of a first half-wave plate 2, a beam splitter 3, a second half-wave plate 4, and a lens 5 arranged sequentially in front of the laser source 1; a neutral density filter 6 is arranged on one side of the beam splitter 3; the laser source emits a laser with a wavelength of 532nm; the half-wave plate can rotate polarized light, and when linearly polarized light is incident perpendicularly on the half-wave plate, the transmitted light is still linearly polarized light. If the angle between the vibration plane and the principal section of the crystal is θ at the time of incidence, the vibration plane of the transmitted linearly polarized light will rotate 2θ from its original orientation; the beam splitter can split a beam of light into two beams, namely optical path 1 and optical path 2; the neutral density filter can attenuate the light intensity. Light in the visible to near-infrared range is attenuated by the same proportion after passing through the neutral density filter, so that the optical element maintains approximately equal light energy transmittance in a wide band;

[0055] A probe module is positioned in front of lens 5, including a rotating sample holder and a long-pass filter 8. The long-pass filter is characterized by allowing light wavelengths in the range of 637–800 nm. A diamond NV center sample 7, under a static magnetic field 26, is placed on the rotating sample holder. The long-pass filter 8 is positioned on the lower surface of the diamond NV center sample 7. Figure 2 As shown, the diamond NV color center sample crystal has four different orientations of the NV symmetry axis in the Cartesian coordinate system, namely 111, 112, 113, 114, 115, 116, 117, 118, 119 ... Diamond NV color center samples emit fluorescence signals with a wavelength range of 637–750 nm under the influence of laser, microwave sources and the magnetic field to be measured. The fluorescence intensity is related to the strength of the magnetic field to be measured.

[0056] The magnetometry electronics module includes: a first photodetector PD10, a second photodetector PD9, a first main amplifier 11, a second main amplifier 13, a first filter 12, a second filter 14, a third filter 17, a phase cancellation circuit 15, a differentiator 16, an analog-to-digital converter module ADC18, an FPGA module 19, a digital-to-analog converter module DAC20, and an oscilloscope 27.

[0057] A first photodetector PD10, a first main amplifier 11, and a first filter 12 are sequentially arranged in front of the neutral density plate 6.

[0058] The second photodetector PD9 is placed directly below the long-wave pass filter 8 and is connected in sequence to the second main amplifier 13 and the second filter 14;

[0059] The outputs of the first filter 12 and the second filter 14 are connected to the input of the cancellation circuit 15. The output of the cancellation circuit 15 outputs two signals: one connected to the oscilloscope 27, and the other connected sequentially to the differentiator 16, the third filter 17, the analog-to-digital converter (ADC) 18, the FPGA module 19, and the digital-to-analog converter (DAC) 20. The first photodetector PD, the second photodetector PD, the first main amplifier, the second main amplifier, the first filter, the second filter, the third filter, the cancellation circuit, and the differentiator constitute an analog signal conditioning circuit. Its characteristic is that it performs noise reduction, amplification, filtering, noise reduction, and differentiation processing on the analog signal to obtain a fluorescence modulation signal. The cancellation circuit uses analog circuits, such as subtraction circuits, to process the laser source noise signal and the diamond NV color center fluorescence signal, eliminating the error signal caused by the laser source's operating disturbance. The oscilloscope is characterized by judging whether the direction of the static magnetic field to be measured satisfies the condition of being parallel only to one of the four NV axes of the diamond NV color center sample after fine-tuning the rotating sample holder by the fluorescence signal waveform. The ADC module can sample and digitize the modulated fluorescence signal and send the digital signal to the FPGA for data processing via SPI communication.

[0060] like Figure 3 As shown, the FPGA includes a data communication unit, a data storage unit, and a data processing unit; the data communication unit includes a communication unit_Ethernet and a communication unit_SPI; the data storage unit includes a data storage unit_FL mod Data storage unit_f mw Data storage unit_V n Data storage unit_f n Data storage unit_B e The data processing unit includes a FIFO data buffer unit, a matrix integration and segmentation unit, a segmented matrix operation unit, a logic XOR unit_M', a logic XOR unit_N', a frequency extraction unit_M, a frequency extraction unit_N, and a field strength calculation unit.

[0061] The FPGA module communicates via the SPI unit and the digital-to-analog converter (DAC). The DAC outputs an analog signal v. o It interacts with different subsequent magnetic signal processing systems / devices.

[0062] The microwave module includes: microwave source 23, shield 24, power amplifier 25, PC terminal 22, and switch 21;

[0063] The microwave source 23 is connected to the FPGA module 19 via the switch 21; the switch 21 is also connected to the PC terminal 22.

[0064] Microwave source 23 is connected in sequence to shield 24 and power amplifier 25; the output terminal of power amplifier 25 is connected to diamond NV color center sample 7; the microwave source is characterized by performing cyclic frequency sweeping operation with a microwave frequency range of 2700MHz-3100MHz as one working cycle, and the time of one frequency sweeping working cycle of the microwave source is T; the isolator is characterized by enabling the microwave signal to be transmitted unidirectionally towards the diamond NV color center sample; the power amplifier is characterized by linearly amplifying the power of the microwave signal emitted by the microwave source; the PC terminal controls the microwave source to send the frequency of the microwave source during frequency sweeping operation according to the sampling frequency f of the analog-to-digital converter (ADC) module via Ethernet communication through a switch; the switch is characterized by serving as a communication transmission hub between the microwave source, the PC terminal, and the FPGA.

[0065] Laser source 1 emits laser light of a certain wavelength, which is split into two beams after passing through the first half-wave plate 2 and beam splitter 3. Beam path 1 passes through neutral density plate 6 and is received by the first photodetector PD10, which converts it into a first electrical signal and transmits it to the first main amplifier 11 and the first filter 12. The first filter 12 outputs a noise floor signal and inputs it into the phase cancellation circuit 15. Beam path 2 passes through the second half-wave plate 4 and lens 5 and then illuminates the diamond NV color center sample 7.

[0066] Under the control of PC 22, microwave source 23 emits microwave signals which are transmitted to diamond NV color center sample 7 after passing through shield 24 and power amplifier 25 in sequence.

[0067] The diamond NV color center sample 7 emits a fluorescence signal, which is received by the second photodetector PD9 after passing through the long-pass filter 8 and converted into a second electrical signal. The signal is then transmitted to the second main amplifier 13 and the second filter 14 in sequence. The second filter 14 outputs the undenoised fluorescence signal and inputs it into the phase cancellation circuit 15.

[0068] Another path of light passes through the neutral density plate 6 and is received by the first photodetector PD10. After being converted into a first electrical signal, it is transmitted sequentially to the first main amplifier 11 and the first filter 12. The first filter 12 outputs the noise floor signal and inputs it into the phase cancellation circuit 15.

[0069] The cancellation circuit 15 subtracts the background noise signal from the undenoised fluorescence signal to obtain the denoised fluorescence signal. One path is connected to the oscilloscope 27, and the other path is processed by the differentiator 16 and the third filter 17 to obtain the fluorescence modulation signal, which is then transmitted to the analog-to-digital converter module ADC18 and the FPGA module 19 in sequence.

[0070] Initially, the bias voltage of the differentiator 16 is 0V. By adjusting the sample holder to rotate arbitrarily, the angle at which the static magnetic field 26 acts on the sample 7 changes. The fluorescence signal on the oscilloscope 27 is observed. Within one sweep cycle of the microwave source, the fluorescence signal curve shows four distinct troughs, such as... Figure 4 As shown, if the direction of the static magnetic field to be measured is determined to be parallel to one of the four NV axes of the diamond NV color center sample, then a bias voltage is applied to the differentiator 16 to make the differentiator 16 work.

[0071] PC 22 sends the microwave frequency of microwave source 23 to FPGA module 19 through switch 21;

[0072] FPGA module 19 processes the received fluorescence modulation signal and microwave frequency to obtain the strength B of the static magnetic field 28. e The data is then transmitted to the digital-to-analog converter (DAC20) for processing, and the final analog magnetic field strength V is output. o .

[0073] The diamond NV center magnetic field measurement system based on data matrix analysis is characterized in that the FPGA module 19 processes the received fluorescence modulation signal and microwave frequency within one sweep cycle according to the following steps:

[0074] Step 1, Data Storage Unit _FL modThe communication unit _SPI receives the fluorescence modulation signal sent by the analog-to-digital converter ADC18. If, within one working cycle of the microwave source frequency sweep, the logic OR unit receives the nth fluorescence modulation signal within the range 0 ± Δ, then its logic value K is set. n If it is 0, otherwise, set its logical value K. n =1; K n This represents the logic value of the nth fluorescence modulation signal, and Δ represents the allowable error range.

[0075] Step 2: The logical OR unit pairs the nth and (n+1)th logical values ​​K. n K n+1 Perform an OR operation; if the OR operation result is 1, then the nth and (n+1th)th fluorescence modulation signals are determined to be valid signals and stored in the data storage unit _V. n In the middle, denoted as V n and V n+1 Data storage unit _f n Receive and store the nth valid signal V n The sweep frequency is denoted as f. n The (n+1)th valid signal V n+1 The sweep frequency is denoted as f. n+1 Otherwise, it is considered an invalid signal.

[0076] Step 3: The matrix integration block unit integrates all valid signals V n and its sweep frequency f n By sequentially integrating, a matrix is ​​obtained.

[0077] Step 4: Matrix integration and partitioning unit: Divide matrix A into 2×2 partitioned matrices according to columns:

[0078] When n is odd, add a column of identical data after the last column of matrix A, denoted as A = (A1 A2 A3…A…). i …A (n+1) / 2 );

[0079] When n is even, it is denoted as A = (A1 A2 A3…A…). i …A n / 2 ); where A i Let A represent the i-th block matrix. (n+1) / 2 Let A represent the (n+1) / 2th block matrix. n / 2 This represents the n / 2th block matrix;

[0080] Step 5: The block matrix operation unit uses equations (1) and (2) to divide matrix A into blocks respectively. iThe calculation is performed to obtain matrices M and N, and the data of matrices M and N are stored and sent to the logic XOR unit _M', logic XOR unit _N', frequency extraction unit _M and frequency extraction unit _N;

[0081]

[0082]

[0083] M = (M1 M2 M3…M) i …M n / 2 (3)

[0084] N = (N1 N2 N3 … N) i …N n / 2 (4)

[0085] In equations (3) and (4), M i Let N represent the i-th block matrix in matrix M. i This represents the i-th block matrix in matrix N;

[0086] Step 6: The logical XOR unit _M' is applied to the i-th block matrix M. i Each element in each column is evaluated. If any element in a column falls within the range of 0 ± Δ, the corresponding element is set to a logical value of 0; otherwise, the corresponding element is set to a logical value of 1, resulting in the block matrix M. i Logical value matrix M' i ; and for the i-th logical value matrix M' i Perform an XOR logical operation on each column to obtain the XOR result for each column;

[0087] When the XOR result is 1, the frequency extraction unit_M will extract the i-th block matrix M of matrix M. i The non-zero elements in the corresponding column are used as frequency extraction values, denoted as . And continue to perform judgments and XOR logic operations on other block matrices in matrix M;

[0088] When the XOR result is 0, the logical XOR unit _M' judges the logical value matrix M'. i Should both columns be subjected to an XOR logical operation?

[0089] If the logical value matrix M' i If both columns have been processed, then the other blocks in matrix M are judged and subjected to XOR logical operations.

[0090] If the logical value matrix M' i If the operations on both columns are not fully completed, then the logical value matrix M' iAfter performing an XOR operation on the next column of elements, the other block matrices in matrix M are then judged and subjected to XOR operations.

[0091] Step 7: The logic XOR unit _N' performs judgment and XOR logic operation on the block matrix in matrix N according to step 4, and obtains the frequency extraction value through the frequency extraction unit _N, denoted as .

[0092] Step 8: Within one working cycle, four extraction frequency values ​​are obtained according to the process of steps 1-7, and after being sorted in ascending order, they are recorded as f1, f2, f3, and f4; the field strength calculation unit uses equation (5) to calculate the intensity B of the static magnetic field (28). e ;

[0093]

[0094] In equation (5), g is the Landé factor, μ B It is the Bohr magneton.

Claims

1. A diamond NV color center magnetic field measurement system based on data matrix analysis, characterized in that, include: Optical path module, microwave module, probe module, and magnetometry electronics module; The optical path module consists of a first half-wave plate (2), a beam splitter (3), a second half-wave plate (4), and a lens (5) arranged sequentially in front of the laser source (1); a neutral density plate (6) is arranged on one side of the beam splitter (3); The probe module is provided in front of the lens (5) and includes: a rotating sample holder and a long-pass filter (8); A diamond NV color center sample (7) under a static magnetic field (28) is placed on the rotating sample holder; a long-pass filter (8) is provided on the lower surface of the diamond NV color center sample (7); The magnetic measurement electronics module includes: a first photodetector PD (10), a second photodetector PD (9), a first main amplifier (11), a second main amplifier (13), a first filter (12), a second filter (14), a third filter (17), a phase cancellation circuit (15), a differentiator (16), an analog-to-digital converter (ADC) (18), an FPGA module (19), and a digital-to-analog converter (DAC) (20); The first photodetector PD (10), the first main amplifier (11), and the first filter (12) are sequentially arranged in front of the neutral density sheet (6); The second photodetector PD (9) is placed close to the bottom of the long-pass filter (8) and connected in sequence to the second main amplifier (13) and the second filter (14); The outputs of the first filter (12) and the second filter (14) are connected to the input of the cancellation circuit (15). The output of the cancellation circuit (15) consists of two signals, one of which is connected to an oscilloscope (27), and the other is connected in sequence to a differentiator (16), a third filter (17), an analog-to-digital converter (ADC) (18), an FPGA module (19), and a digital-to-analog converter (DAC) (20). The microwave module includes: a microwave source (23), a shield (24), a power amplifier (25), a PC terminal (22), and a switch (21); The microwave source (23) is connected to the FPGA module (19) through the switch (21); the switch (21) is also connected to the PC (22); The microwave source (23) is connected in sequence to the shield (24) and the power amplifier (25); the output terminal of the power amplifier (25) is connected to the diamond NV color center sample (7); The laser source (1) emits a laser of a certain wavelength and passes through the first half-wave plate (2) and the beam splitter (3) in sequence to split into two beams. One beam passes through the second half-wave plate (4) and the lens (5) in sequence and then illuminates the diamond NV color center sample (7). Under the control of the PC (22), the microwave source (23) emits microwave signals and transmits them to the diamond NV color center sample (7) after passing through the shield (24) and power amplifier (25) in sequence. The diamond NV color center sample (7) emits a fluorescence signal, which is received by the second photodetector PD (9) after passing through the long-pass filter (8) and converted into a second electrical signal. The signal is then transmitted to the second main amplifier (13) and the second filter (14) in sequence. The second filter (14) outputs the undenoised fluorescence signal and inputs it into the phase cancellation circuit (15). Another path of light passes through the neutral density plate (6) and is received by the first photodetector PD (10). After being converted into a first electrical signal, it is transmitted sequentially to the first main amplifier (11) and the first filter (12). The first filter (12) outputs the noise floor signal and inputs it into the phase cancellation circuit (15). After the cancellation circuit (15) processes the undenoised fluorescence signal and the background noise signal, the fluorescence modulation signal is obtained after being processed by the differentiator (16) and the third filter (17) and then transmitted to the analog-to-digital conversion module ADC (18) and the FPGA module (19) in sequence. The PC (22) sends the microwave frequency of the microwave source (23) to the FPGA module (19) through the switch (21); The FPGA module (19) processes the received fluorescence modulation signal and microwave frequency to obtain the strength of the static magnetic field (28). The data is then transmitted to the digital-to-analog converter module DAC (20) for processing, and the final simulated magnetic field strength V0 is output. The FPGA module (19) processes the received fluorescence modulation signal and microwave frequency within one sweep cycle according to the following steps: Step 1: If the FPGA module (19) receives the nth fluorescence modulation signal within the range of a working cycle, then... If it is internal, then set its logical value. If it is 0, otherwise, set its logical value to 0. =1, This represents the logic value of the nth fluorescence modulation signal; Indicates the allowable error range; Step 2: For the nth and (n+1)th logical values , Perform an OR operation; when the OR operation result is 1, then the nth and (n+1)th fluorescence modulation signals are determined to be valid signals, denoted as . and and the nth valid signal The sweep frequency is denoted as The (n+1)th valid signal The sweep frequency is denoted as Otherwise, it is considered an invalid signal. Step 3: Collect all valid signals and its sweep frequency By sequentially integrating, a matrix is ​​obtained. ; Step 4: The matrix Divided into dimensions by column The block matrix: When n is odd, for the matrix Add a column of identical data after the last column of data, denoted as . ; When n is even, it is denoted as ;in, This represents the i-th block matrix. This represents the (n+1) / 2th block matrix. This represents the n / 2th block matrix; Step 5: Use equations (1) and (2) to define the block matrix respectively. Calculations are performed to obtain the matrix. and ; (1) (2) (3) (4) In equations (3) and (4), Representation matrix The first in i A block matrix, Representation matrix The first in i A block matrix; Step 6, regarding the first i block matrix The elements in each column are evaluated. If any element in a column is in the correct position... If the element falls within the specified range, set its logical value to 0; otherwise, set its logical value to 1, thus obtaining the block matrix. Logical value matrix ; and regarding the first i Logical value matrix Perform an XOR logical operation on each column to obtain the XOR result for each column; When the XOR result is 1, the first... i block matrix The non-zero elements in the corresponding column are used as frequency extraction values, denoted as . and continue with the matrix Perform judgment and XOR logic operations on other block matrices in the matrix; When the XOR result is 0, the logical value matrix is ​​judged. Should both columns be XORed? If the logical value matrix If both columns have been processed, then the matrix... Perform judgment and XOR logic operations on other block matrices in the matrix; If the logical value matrix If the operations on both columns are not fully completed, then the logical value matrix... After performing an XOR operation on the next column of elements, then process the matrix. Perform judgment and XOR logic operations on other block matrices in the matrix; Step 7: Perform the matrix according to step 4. The block matrix is ​​used for judgment and XOR logic operation to obtain the frequency extraction value, denoted as . ; Step 8: Within one work cycle, obtain four extraction frequency values ​​according to the processes of steps 1-7, sort them in ascending order, and record them as follows: , , and The strength of the static magnetic field (28) is calculated using equation (5). ; (5) In equation (5), For Landes factor, It is the Bohr magneton.

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