A frequency agile tracking quantum sensing system based on diamond NV color centers

Abstract

The present invention discloses a frequency agile tracking quantum sensing system based on diamond NV color center, which realizes fast frequency jump by quickly changing the frequency tuning word in a register, utilizes the linear region of the fluorescence amplitude and frequency of the first-order differential spectrum line of the diamond NV color center fluorescence spectrum line, and demodulates the amplitude change through a phase-locked module so that a microwave source module can quickly compensate for the frequency deviation value, completes the fast dynamic tracking of the microwave resonance frequency, greatly shortens the measurement time of the system once, and increases the sampling rate of the quantum sensing system to more than 10k, meeting the demand for backward compatibility of mutual inductors in the field of power measurement.

Description

Technical Field

[0001] The present invention relates to the field of quantum sensing technology, and in particular to a frequency agile tracking quantum sensing system based on diamond NV color centers. Background Art

[0002] Quantum sensing technology refers to the use of quantum effects to measure certain physical quantities, such as magnetic field, electric field, temperature and other physical quantities. It has obvious advantages over traditional sensors in terms of sensitivity, environmental adaptability and range. At present, quantum sensing systems mainly include cold atoms, ion traps, atomic vapor, superconducting circuits and solid-state spins. Among them, the solid-state spin system of diamond NV color center has excellent light readout and polarization properties, coherence time of milliseconds, and its high-sensitivity measurement at room temperature makes it have broad prospects in industrial applications. Especially in the field of power measurement, the reliable operation of the power system and the real-time status detection of electrical equipment are inseparable from the accurate and real-time acquisition of voltage and current information. Diamond NV color center quantum sensing, which is sensitive to electric and magnetic fields, is a hot topic for researchers.

[0003] Based on the detection of electric and magnetic fields by diamond NV color center quantum sensing, the ODMR spectrum can be obtained by continuous light detection magnetic resonance method, that is, using a microwave source to sweep the frequency in the appropriate frequency region, and drawing the spectrum according to the corresponding relationship between the intensity of fluorescence and the scanning frequency, the microwave resonance frequency value corresponding to the peak and bottom of the absorption peak is obtained, and then the magnitude of the magnetic field is calculated. The smaller the step size of the frequency sweep, the higher the accuracy of the obtained spectrum line, but each time the calculation result is obtained, the microwave source needs to perform a complete frequency sweep in the area, resulting in a complete magnetic field measurement that takes seconds, and the sampling rate of the system does not meet the requirements of backward compatibility of transformers in power system application scenarios.

[0004] Based on this background, the application of diamond NV color center quantum sensing system in the field of power measurement requires reducing the time of a single measurement process of the diamond NV color center quantum sensing system, increasing the sampling rate of the system, and meeting the requirements of backward compatibility of the mutual inductor. Therefore, a frequency agile tracking quantum sensing device and system that can maintain high precision in a large dynamic range is of great significance for the practical application and promotion of quantum sensing systems. Summary of the invention

[0005] In order to solve the technical problems existing in the background technology, the present invention proposes a frequency agile tracking quantum sensing system based on diamond NV color center.

[0006] The present invention proposes a frequency agile tracking quantum sensing system based on diamond NV color center, comprising: an excitation module, a sensing unit, a signal processing unit and a frequency agile microwave unit;

[0007] The sensing unit includes a diamond NV color center sample and a microwave antenna, the excitation module is used to emit laser to the diamond NV color center sample, the microwave antenna is used to act on the diamond NV color center sample with a magnetic field, and the diamond NV color center sample is used to obtain a magnetic field detection signal;

[0008] The signal processing unit includes a digital phase-locking module, a frequency calculation module and an interactive transmission module. The digital phase-locking module is used to extract and demodulate the magnetic field detection signal through the digital phase-locking module. The frequency calculation module is used to calculate the difference ΔV between the real-time signal demodulation amplitude V_1 and the locking amplitude V_0 of the digital phase-locking module, and calculate the resonance frequency deviation Δf according to the conversion coefficient k between the demodulation amplitude and the microwave frequency. The interactive transmission module is used to convert the frequency deviation Δf into a control instruction FTW;

[0009] The frequency agile microwave unit includes a receiving control module, a phase-locked loop (PLL) module and a direct digital frequency synthesizer (DDS) module. The receiving control module is used to convert the control instruction FTW into a frequency control word, the phase-locked loop module is used to provide a reference clock, and the DDS module is used to output a microwave source frequency adjustment signal according to the frequency control word and the reference clock.

[0010] Preferably, the sensing unit further comprises a dichroic mirror and a confocal objective lens;

[0011] The laser emitted by the excitation module is reflected by the dichroic mirror and focused by the confocal objective lens, and then irradiates the diamond NV color center sample. The excitation fluorescence of the diamond NV color center sample is emitted through the confocal objective lens and the dichroic mirror in sequence.

[0012] Preferably, it also includes a fluorescence collection unit, which is used to convert the excitation fluorescence signal of the diamond NV color center sample into an electrical signal.

[0013] Preferably, the fluorescence collection unit comprises a filter set and a photodetector, the filter set is used to filter out light in non-target bands, and the photodetector is used to convert the fluorescence signal into an electrical signal.

[0014] Preferably, it also includes an analog-to-digital conversion module, which is used to convert the electrical signal into a digital signal.

[0015] Preferably, the frequency agile microwave unit further includes a microwave amplification module, and the microwave amplification module is used to amplify the power of the microwave signal output by the DDS module.

[0016] Preferably, the frequency agile microwave unit further comprises a circulator, and the circulator is used to prevent the high-frequency microwave signal from flowing back.

[0017] Preferably, the frequency calculation module is also used to calculate the magnitude of the measured magnetic field in real time according to the relationship between the magnetic field and the microwave resonance frequency.

[0018] Preferably, it also includes a host computer unit, which is used to display the frequency deviation value Δf and the magnetic field strength obtained by the signal processing unit in real time.

[0019] Preferably, it also includes a host computer unit, which is used to control the frequency agile microwave unit to perform frequency sweeping, obtain the optical detection magnetic resonance (ODMR) spectrum line, and lock the microwave resonance frequency and the signal demodulation amplitude at the frequency.

[0020] In the present invention, the proposed frequency agile tracking quantum sensing system based on diamond NV color center realizes rapid frequency jump by quickly changing the frequency tuning word in the register, utilizes the linear region of the fluorescence amplitude and frequency of the first-order differential spectrum line of the diamond NV color center fluorescence spectrum line, and demodulates the amplitude change through the phase-locked module so that the microwave source module can quickly compensate for the frequency deviation value, complete the rapid dynamic tracking of the microwave resonance frequency, greatly shorten the measurement time of the system once, and increase the sampling rate of the quantum sensing system to more than 10k, meeting the demand for backward compatibility of transformers in the field of power measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a connection block diagram of an implementation of a frequency agile tracking quantum sensing system based on diamond NV color centers proposed by the present invention.

[0022] Figure 2 This is a schematic diagram of the optical path of a sensing unit in an embodiment of a frequency agile tracking quantum sensing system based on diamond NV color centers proposed by the present invention.

[0023] Figure 3 This is a connection block diagram of a signal processing unit in an embodiment of a frequency agile tracking quantum sensing system based on diamond NV color centers proposed by the present invention.

[0024] Figure 4 This is a connection block diagram of a frequency agile microwave unit in an embodiment of a frequency agile tracking quantum sensing system based on diamond NV color centers proposed by the present invention.

[0025] Figure 5 This is a quantum sensing principle diagram of an implementation of a frequency agile tracking quantum sensing system based on diamond NV color centers proposed by the present invention. DETAILED DESCRIPTION

[0026] The diamond NV color center is a lattice defect. Its formation process is that a nitrogen atom replaces a carbon atom in diamond, and there is a hole next to it. The defect formed by this structure is the diamond NV color center, which has C_3v symmetry. The theoretical mechanism of quantum sensing based on diamond NV color centers comes from the spin characteristics of diamond NV color centers. The energy level structure of diamond NV color centers can be divided into three states: ground state |g〉, excited state |e〉 and metastable state |s〉, among which the ground state 3A2 and excited state 3E are both triplet states, respectively, Ms = 0 and Ms = ±1. The +1 and -1 states are degenerate states in the absence of a magnetic field, and the degenerate states will separate in the presence of a magnetic field. When the diamond NV color center is irradiated by a laser with a wavelength less than 637nm, the electrons in the ground state of the NV color center will transition to the excited state. Since the electrons in the excited state are unstable, they will produce radiation transitions to the ground state. However, not all electrons in the excited state Ms = ±1 return to the ground state along the original path. Some of them will first decay to a metastable state and then return to the ground state through a radiationless transition. Therefore, when continuous light irradiates the NV color center, the electrons will tend to the ground state Ms = 0. At this time, the laser completes the polarization process and the red fluorescence emitted is the strongest. When microwaves are applied to the NV color center, when the microwave frequency is different from the energy level frequency between Ms = 0 and Ms = ±1, an absorption peak will appear in the fluorescence continuous wave spectrum. Furthermore, due to the Zeeman splitting effect of the diamond NV color center, the Ms = ±1 energy level will degenerate under the action of the magnetic field, and the magnitude of the magnetic field is linearly related to the degree of splitting, as shown in the following formula:

[0027] f = 2.87 GHz ± γ·B·cosθ;

[0028] Among them, f is the microwave resonance frequency, γ is the gyromagnetic ratio, γ≈2.8MHz / Gs, B is the magnetic field strength around the NV color center, and θ is the angle between the magnetic field strength around the NV color center and the NV axis. As can be seen from the formula, the ODMR spectrum can be obtained by continuous light detection magnetic resonance method, that is, using a microwave source to sweep the frequency in an appropriate frequency region, and drawing the spectrum according to the corresponding relationship between the intensity of fluorescence and the scanning frequency, the microwave resonance frequency value corresponding to the peak bottom of the absorption peak is obtained, and then the magnitude of the magnetic field is calculated. The smaller the step size of the frequency sweep, the higher the accuracy of the spectrum line obtained, but each time the calculation result is obtained, the microwave source needs to perform a complete frequency sweep in the area, resulting in a complete magnetic field measurement that needs to reach the second level. The sampling rate of the system does not meet the requirements of backward compatibility of transformers in power system application scenarios.

[0029] Therefore, in order to realize the application of diamond NV, the frequency modulation method is adopted, so that the microwave source emits modulated microwaves, and then the modulated wave carrying fluorescence information is demodulated by using a phase-locked amplifier to obtain the first-order differential spectrum of the original ODMR spectrum line. The linear region of the fluorescence intensity of this spectrum line and the microwave frequency depends on the half-width of the original ODMR spectrum line. The method of using modulated microwaves plus phase-locked amplifier demodulation can reduce noise interference and move the effective signal to a cleaner area of ​​the spectrum.

[0030] like Figures 1 to 5 As shown, Figure 1 This is a connection block diagram of an implementation of a frequency agile tracking quantum sensing system based on diamond NV color centers proposed by the present invention. Figure 2 This is a schematic diagram of the optical path of a sensing unit in one embodiment of a frequency agile tracking quantum sensing system based on diamond NV color centers proposed by the present invention. Figure 3 This is a connection block diagram of a signal processing unit in one embodiment of a frequency agile tracking quantum sensing system based on diamond NV color centers proposed by the present invention. Figure 4 This is a connection block diagram of a frequency agile microwave unit in one embodiment of a frequency agile tracking quantum sensing system based on diamond NV color centers proposed by the present invention. Figure 5 This is a quantum sensing principle diagram of an implementation of a frequency agile tracking quantum sensing system based on diamond NV color centers proposed by the present invention.

[0031] Reference Figure 1 The present invention proposes a frequency agile tracking quantum sensing system based on diamond NV color center, comprising: an excitation module 1, a sensing unit 2, a signal processing unit 4 and a frequency agile microwave unit 6;

[0032] Reference Figure 2 , the sensing unit 2 includes a diamond NV color center sample 9 and a microwave antenna 10, the excitation module 1 is used to emit laser to the diamond NV color center sample 9, the microwave antenna 10 is used to act on the diamond NV color center sample 9 with a magnetic field, and the diamond NV color center sample 9 is used to obtain a magnetic field detection signal;

[0033] Reference Figure 3 The signal processing unit 4 includes a digital phase-locking module 12, a frequency calculation module 13 and an interactive transmission module 14. The digital phase-locking module 12 is used to extract and demodulate the magnetic field detection signal through the digital phase-locking module 12. The frequency calculation module 13 is used to calculate the difference ΔV between the real-time signal demodulation amplitude V_1 and the locking amplitude V_0 of the digital phase-locking module 12, and calculate the resonance frequency deviation Δf according to the conversion coefficient k between the demodulation amplitude and the microwave frequency. The interactive transmission module 14 is used to convert the frequency deviation Δf into a control instruction FTW;

[0034] Reference Figure 4 The frequency agile microwave unit 6 includes a receiving control module 15, a phase-locked loop module 16 and a DDS module 17. The receiving control module 15 is used to convert the control instruction FTW into a frequency control word, the phase-locked loop module 16 is used to provide a reference clock, and the DDS module 17 is used to output a microwave source frequency adjustment signal according to the frequency control word and the reference clock.

[0035] In the specific working process of the frequency agile tracking quantum sensing system based on diamond NV color center of this embodiment, the microwave antenna converts the microwave radio frequency signal into a high-quality alternating magnetic field to act on the diamond NV color center, and the diamond NV color center sample emits fluorescence under the excitation of the laser;

[0036] After the fluorescence signal is converted, it is extracted and demodulated by the digital phase-locked module, and then the difference ΔV between the real-time signal demodulation amplitude V_1 and the locking amplitude V_0 of the digital phase-locked module 12 is calculated by the frequency calculation module 13, and the resonance frequency deviation Δf is calculated according to the conversion coefficient k between the demodulation amplitude and the microwave frequency, and the frequency deviation Δf is converted into a control instruction FTW by the interactive transmission module 14;

[0037] The receiving control module 15 converts the control instruction FTW into a frequency control word, and the DDS module 17 outputs a microwave source frequency adjustment signal according to the frequency control word and the reference clock provided by the phase-locked loop module 16, thereby achieving frequency agile following of the diamond NV color center.

[0038] In this embodiment, the proposed frequency agile tracking quantum sensing system based on diamond NV color center realizes rapid frequency jump by quickly changing the frequency tuning word in the register, and utilizes the linear region of the fluorescence amplitude and frequency of the first-order differential spectrum of the diamond NV color center fluorescence spectrum. The phase-locked module demodulates the amplitude change so that the microwave source module can quickly compensate for the frequency deviation value, complete the rapid dynamic tracking of the microwave resonance frequency, greatly shorten the measurement time of the system, and increase the sampling rate of the quantum sensing system to more than 10k, meeting the demand for backward compatibility of transformers in the field of power measurement.

[0039] In a specific embodiment, the excitation module is a 532nm laser. The sensing unit 2 also includes a dichroic mirror 7 and a confocal objective lens 8; the laser emitted by the excitation module 1 is reflected by the dichroic mirror 7 to the confocal objective lens 8 for focusing, and then irradiates the diamond NV color center sample 9, and the excitation fluorescence of the diamond NV color center sample 9 is emitted through the confocal objective lens 8 and the dichroic mirror 7 in turn.

[0040] Specifically, the dichroic mirror is tilted 45° to reflect 532nm laser light, and through the 600-800nm ​​band fluorescence, the confocal objective lens focuses the 532nm laser light reflected by the dichroic mirror. The diamond NV color center sample is a block solid containing a certain concentration of diamond NV color centers. The microwave antenna converts the microwave radio frequency signal into a high-quality alternating magnetic field to act on the diamond NV color center. The diamond NV color center sample emits red fluorescence in the 600-800nm ​​band under the excitation of the 532nm laser, which is collected by the confocal objective lens and then transmitted through the dichroic mirror.

[0041] During the fluorescence signal conversion process, the system of this embodiment further includes a fluorescence collection unit 3, which is used to convert the excitation fluorescence signal of the diamond NV color center sample 9 into an electrical signal.

[0042] Specifically, the fluorescence collection unit 3 includes a filter set and a photodetector, wherein the filter set is used to filter out light in non-target bands, and the photodetector is used to convert the fluorescence signal into an electrical signal.

[0043] In addition, this embodiment further includes an analog-to-digital conversion module, and the analog-to-digital conversion module is used to further convert the electrical signal into a digital signal.

[0044] In the specific design of the frequency agile microwave unit, the frequency agile microwave unit 6 further includes a microwave amplification module 18, which is used to amplify the power of the microwave signal output by the DDS module 17. In addition, the frequency agile microwave unit 6 further includes a circulator 19, which is used to prevent the high-frequency microwave signal from flowing back.

[0045] In other specific embodiments, the frequency calculation module 13 is also used to calculate the magnitude of the measured magnetic field in real time according to the relationship between the magnetic field and the microwave resonance frequency. The system of this embodiment also includes a host computer unit 5, which is used to display the frequency deviation value Δf and the magnetic field strength obtained by the signal processing unit 4 in real time. In the specific control method of the host computer, the host computer unit 5 can also be used to control the frequency agile microwave unit 6 to sweep the frequency, obtain the ODMR spectrum, and lock the microwave resonance frequency and the signal demodulation amplitude at this frequency.

[0046] The frequency agile tracking quantum sensing system based on diamond NV color centers of this embodiment is described in detail below through specific examples.

[0047] The present invention provides a frequency agile tracking quantum sensing system based on diamond NV color centers, such as Figure 1As shown, the frequency agile tracking quantum sensing system based on diamond NV color center includes an excitation module 1, a sensing unit 2, a fluorescence collection unit 3, a signal processing unit 4, a host computer unit 5, and a frequency agile microwave unit 6; wherein the excitation module is a 532nm laser, the laser power of which is controlled within 400mW in this embodiment, and emits a 532nm laser to the sensing unit 2, the purpose of which is to polarize the diamond NV color center;

[0048] like Figure 2 As shown, the sensing unit includes a dichroic mirror 7, a confocal objective lens 8, a diamond NV color center sample 9, and a microwave antenna 10; wherein the dichroic mirror 7 is tilted at 45°, reflects 532nm laser, and passes fluorescence in the 600-800nm ​​band; the confocal objective lens 8 focuses the 532nm laser reflected by the dichroic mirror 7, and irradiates the diamond NV color center sample 9 placed on the microwave antenna 10; wherein the diamond NV color center sample 9 is a block solid containing a certain concentration of diamond NV color centers, and the microwave antenna 10 converts the microwave radio frequency signal into a high-quality alternating magnetic field to act on the diamond NV color center, and the diamond NV color center sample 9 emits red fluorescence in the 600-800nm ​​band under the excitation of the 532nm laser, which is collected by the confocal objective lens 8. Since the dichroic mirror 7 can pass the light in the 600-800nm ​​band, the red fluorescence is transmitted to the fluorescence collection unit 3 via the dichroic mirror 7;

[0049] The fluorescence collection unit 3 includes a filter set and a photodetector; the filter set filters out light in non-target bands and retains the red fluorescence in the 600-800nm ​​band generated by the diamond NV color center sample 9; the photodetector converts the red fluorescence signal into an electrical signal, which is transmitted to the signal processing unit 4;

[0050] like Figure 3 The signal processing unit 4 includes an analog-to-digital conversion module (ADC) 11, a digital phase-locking module 12, a frequency calculation module 13, and an interactive transmission module 14; wherein the ADC 11 collects the analog signal output by the photodetector and converts it into a digital signal; the digital phase-locking module 12 extracts and demodulates the signal with fluorescence amplitude information; the frequency calculation module 13 calculates the difference ΔV between the real-time signal demodulation amplitude V_1 and the locking amplitude V_0 of the digital phase-locking module 12, and calculates the resonance frequency deviation Δf according to the conversion coefficient k between the demodulation amplitude and the microwave frequency; wherein the interactive transmission module 14 plays the following two roles: one is to transmit the real-time signal demodulation amplitude V_1 and the resonance frequency deviation Δf to the upper computer unit in real time, and the other is to convert the frequency deviation Δf into a control instruction FTW and transmit it to the frequency agile microwave unit;

[0051] Among them, the relationship between the demodulation amplitude difference ΔV and the resonance frequency deviation Δf is as follows: Figure 5 As shown, in the linear region of the first-order differential demodulation spectrum of the ODMR spectrum, the demodulation amplitude and the resonance frequency show a linear correlation, corresponding to ΔV=k*Δf, and the conversion coefficient k is the slope of the linear region. For the same diamond NV color center sample, when the area and area of ​​the diamond NV color center sample 9 receiving 532nm laser irradiation remain unchanged, the value of the slope k is unchanged. Therefore, by measuring the change of the demodulation amplitude in real time, the change of the resonance frequency can be obtained, and then the resonance frequency in the new magnetic field environment can be obtained. The size of the resonance frequency is based on the relationship between the resonance frequency of the diamond NV color center and the magnetic field size. Get the magnitude of the measured magnetic field;

[0052] like Figure 4 As shown, the frequency agile microwave unit includes a receiving control module 15, a phase-locked loop (PLL) unit 16, a DDS module 17, a microwave amplification module 18, and a circulator 19; wherein the receiving control module 15 receives the control instruction FTW transmitted by the interactive transmission module 14, converts it into a frequency control word, and transmits it to the DDS module 17; the phase-locked loop (PLL) unit 16 provides a high-speed and stable reference clock for the DDS module 17; the DDS module 17 outputs a signal of a specified frequency according to the frequency control word and the clock provided by the phase-locked loop (PLL) unit 16, and the center frequency of the microwave signal at this time is the same as the resonance frequency; the microwave amplification module 18 amplifies the power of the high-frequency microwave signal output by the DDS module 17; the circulator 19 prevents the high-frequency microwave signal from flowing back and damaging the electronic devices in the frequency agile microwave unit, thereby protecting the system safety; wherein, since the output frequency of the direct digital frequency synthesizer (DDS) depends on the frequency tuning word, by utilizing the advantages of FPGA parallel computing speed and high-speed SPI transmission, the frequency tuning word in the DDS module can be changed in a very short time to specify the center frequency of the output microwave signal, thereby realizing frequency agile following. Since the time for the signal demodulation amplitude change obtained in each measurement is very short, and the time for the frequency to follow the changing resonance frequency is very short, it also makes up for the problem of the narrow linear region of the first-order differential demodulation spectrum of the ODMR spectrum to a certain extent; compared with the system of measuring the magnetic field by the frequency domain sweep method of the diamond NV color center, the frequency agile design greatly reduces the time for the system to complete a measurement result, improves the measurement bandwidth of the system, and can meet the requirements for the sensor sampling rate when measuring the power system;

[0053] The host computer unit 5 has two functions: one is to control the frequency agile microwave unit 6 to perform frequency sweeping, obtain the optical detection magnetic resonance (ODMR) spectrum line, and lock the microwave resonance frequency and the signal demodulation amplitude at this frequency; the other is to display the frequency deviation value Δf in real time through the signal processing unit 4, and calculate the size of the measured magnetic field in real time according to the relationship between the magnetic field and the microwave resonance frequency.

[0054] Among them, the filter group is a low-pass filter and a high-pass filter, which filters out light in the 600-800nm ​​band; the locked amplitude is the demodulation amplitude corresponding to the trough of the ODMR spectrum line obtained by the frequency agile microwave unit by equally spaced frequency scanning in the 2.7-3GHz frequency domain; the host computer unit 5 first locks the resonant frequency at a trough of the ODMR spectrum line and the demodulation amplitude at this frequency, which is equivalent to the initialization operation of the quantum sensing system before performing frequency agile following work, and then performs frequency agile following.

[0055] The frequency agile tracking quantum sensing system based on diamond NV color centers of this embodiment can achieve the following beneficial effects:

[0056] (1) The present invention realizes rapid frequency jump by rapidly changing the frequency tuning word in the register, utilizes the linear region of the fluorescence amplitude and frequency of the first-order differential spectrum of the diamond NV color center fluorescence spectrum, and demodulates the amplitude change through the phase-locked module so that the microwave source module can quickly compensate for the frequency deviation value, complete the rapid dynamic tracking of the microwave resonance frequency, greatly shorten the measurement time of the system, and increase the sampling rate of the quantum sensing system to more than 10k, meeting the demand for backward compatibility of transformers in the field of power measurement.

[0057] (2) In order to make the quantum sensing system actually applicable to power measurement scenarios, the present invention adopts small boards for the development of phase-locked modules and microwave source modules in response to the complexity of the on-site environment. While ensuring the performance, the volume of the quantum sensing device and system is greatly reduced, the portability is increased, and the miniaturization and integration development are facilitated.

[0058] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A frequency agile tracking quantum sensing system based on diamond NV color centers, characterized in that: include: An excitation module (1), a sensing unit (2), a signal processing unit (4) and a frequency agile microwave unit (6); The sensing unit (2) comprises a diamond NV color center sample (9) and a microwave antenna (10), the excitation module (1) is used to emit laser light to the diamond NV color center sample (9), the microwave antenna (10) is used to apply a magnetic field to the diamond NV color center sample (9), and the diamond NV color center sample (9) is used to obtain a magnetic field detection signal; The signal processing unit (4) comprises a digital phase-locking module (12), a frequency calculation module (13) and an interactive transmission module (14); the digital phase-locking module (12) is used to extract and demodulate the magnetic field detection signal through the digital phase-locking module (12); and the frequency calculation module (13) is used to calculate the difference between the real-time signal demodulation amplitude V_1 and the locking amplitude V_0 of the digital phase-locking module (12). , and calculate the resonance frequency deviation based on the conversion coefficient k between the demodulated amplitude and the microwave frequency The interactive transmission module (14) is used to transmit the frequency deviation Converted into control instruction FTW; The frequency agile microwave unit (6) comprises a receiving control module (15), a phase-locked loop module (16) and a DDS module (17), wherein the receiving control module (15) is used to convert the control instruction FTW into a frequency control word, the phase-locked loop module (16) is used to provide a reference clock, and the DDS module (17) is used to output a microwave source frequency adjustment signal according to the frequency control word and the reference clock; It also includes a host computer unit (5), which is used to control the frequency agile microwave unit (6) to perform frequency sweeping, obtain ODMR spectrum lines, and lock the microwave resonance frequency and the signal demodulation amplitude at the frequency.

2. The frequency agile tracking quantum sensing system based on diamond NV color centers according to claim 1 is characterized in that: The sensing unit (2) further comprises a dichroic mirror (7) and a confocal objective lens (8); The laser light emitted by the excitation module (1) is reflected by the dichroic mirror (7) to the confocal objective lens (8) for focusing, and then irradiates the diamond NV color center sample (9). The excitation fluorescence of the diamond NV color center sample (9) is emitted in sequence through the confocal objective lens (8) and the dichroic mirror (7).

3. The frequency agile tracking quantum sensing system based on diamond NV color center according to claim 1 is characterized in that: It also comprises a fluorescence collection unit (3), wherein the fluorescence collection unit (3) is used to convert the excitation fluorescence signal of the diamond NV color center sample (9) into an electrical signal.

4. The frequency agile tracking quantum sensing system based on diamond NV color center according to claim 3 is characterized in that: The fluorescence collection unit (3) comprises a filter set and a photodetector, wherein the filter set is used to filter out light in a non-target wavelength band, and the photodetector is used to convert the fluorescence signal into an electrical signal.

5. The frequency agile tracking quantum sensing system based on diamond NV color center according to claim 3 is characterized in that: It also includes an analog-to-digital conversion module, which is used to convert the electrical signal into a digital signal.

6. The frequency agile tracking quantum sensing system based on diamond NV color center according to claim 1, characterized in that: The frequency agile microwave unit (6) further comprises a microwave amplification module (18), wherein the microwave amplification module (18) is used to amplify the power of the microwave signal output by the DDS module (17).

7. The frequency agile tracking quantum sensing system based on diamond NV color center according to claim 1 is characterized in that: The frequency agile microwave unit (6) further comprises a circulator (19), wherein the circulator (19) is used to prevent the high-frequency microwave signal from flowing back.

8. The frequency agile tracking quantum sensing system based on diamond NV color center according to claim 1, characterized in that: The frequency calculation module (13) is also used to calculate the magnitude of the measured magnetic field in real time according to the relationship between the magnetic field and the microwave resonance frequency.

9. The frequency agile tracking quantum sensing system based on diamond NV color centers according to claim 8, characterized in that: It also includes a host computer unit (5), which is used to display the frequency deviation value obtained by the signal processing unit (4) in real time and magnetic field strength.

Images