Diamond NV color center-based low-frequency quantum electric field measurement method and comprehensive performance test platform

Abstract

The invention relates to the technical field of electric field measurement, in particular to a low-frequency quantum electric field measurement method based on a diamond NV color center and a comprehensive performance test platform, and the method comprises the steps: controlling an electrode system to which alternating voltage is applied, and enabling the electrode system to generate an alternating electric field; based on a magnetic field generated by the alternating electric field in an electric field area generated by the electrode system, executing magnetic field response measurement on an NV color center in a magnetic field response area to obtain magnetic field response data; and based on the magnetic field response data and the geometric parameters of the electrode system, performing electric field calculation processing to obtain the electric field intensity of the alternating electric field. According to the invention, the precision and reliability of low-frequency electric field measurement are effectively improved.

Description

Technical Field

[0001] This application relates to the field of electric field measurement technology, and in particular to a low-frequency quantum electric field measurement method and comprehensive performance testing platform based on diamond NV color centers. Background Technology

[0002] Low-frequency electric field measurement refers to the technique of quantitatively detecting alternating electric fields in the frequency range of 20Hz to 2.5kHz. It is widely used in electromagnetic compatibility testing, bioelectromagnetic effects research, and environmental electromagnetic monitoring. Within this frequency band, the electric field changes relatively slowly, requiring highly sensitive sensors for direct measurement, and is easily affected by environmental noise.

[0003] Traditional low-frequency electric field measurement techniques mainly include two methods: capacitive sensors and antenna sensors. Capacitive sensors measure electric field strength by utilizing the charge change induced on the sensing electrodes by an electric field. They typically consist of two parallel plate electrodes, and the electric field strength is determined by measuring the charge or voltage on the sensing electrodes. Antenna sensors, on the other hand, are based on the principle of electromagnetic induction, acquiring electric field information by measuring the voltage induced in the antenna by the electric field.

[0004] However, while these traditional methods can meet basic measurement needs in a static laboratory environment, they generally suffer from drawbacks such as limited sensitivity, narrow bandwidth, and susceptibility to interference, making it difficult to meet the measurement accuracy and reliability requirements of practical applications. Summary of the Invention

[0005] This application addresses the problems of difficulty in direct measurement of low-frequency electric fields, insufficient sensitivity, and susceptibility to interference in existing technologies by providing a low-frequency electric field measurement technology based on indirect magnetic field measurement, which effectively improves the accuracy and reliability of low-frequency electric field measurement.

[0006] In a first aspect, this application provides a low-frequency electric field measurement method based on diamond NV centers, executed by a controller, the method comprising: Control the electrode system to which an alternating voltage is applied, so that the electrode system generates an alternating electric field; Based on the magnetic field generated by the alternating electric field in the electric field region of the electrode system, the magnetic field response is measured on the NV color center located in the magnetic field response region to obtain magnetic field response data; Based on the magnetic field response data and the geometric parameters of the electrode system, the electric field strength of the alternating electric field is obtained by performing electric field calculation.

[0007] Secondly, this application also provides a comprehensive performance testing platform for low-frequency quantum electric field measurement based on diamond NV color centers, the platform comprising: An electrode system control device is used to control an electrode system to which an alternating voltage is applied, so that the electrode system generates an alternating electric field. A magnetic field response measurement device is used to measure the magnetic field response of NV color centers located within the magnetic field response region based on the magnetic field generated by the alternating electric field in the electric field region generated by the electrode system, and to acquire magnetic field response data. The electric field calculation and processing device is used to perform electric field calculation and processing based on magnetic field response data and the geometric parameters of the electrode system to obtain the electric field strength of the alternating electric field.

[0008] The aforementioned low-frequency quantum electric field measurement method and comprehensive performance testing platform based on diamond NV centers (nodal radix centers) generates an alternating electric field by precisely controlling the electrode system. This field is then used to generate a naturally occurring magnetic field within the electric field region of the electrode system, serving as the measurement medium. Furthermore, the NV center, a highly sensitive quantum sensor, is employed to precisely measure the magnetic field. This indirect measurement method cleverly circumvents the inherent problems of weak and easily interfered low-frequency electric field signals, shifting the measurement challenge from the electric field domain to the magnetic field domain, and fully leveraging the inherent advantages of NV centers in magnetic field measurement.

[0009] By combining magnetic field response data with the geometric parameters of the electrode system for electric field calculation, a reliable conversion mechanism from magnetic field measurements to electric field strength is established, ensuring the accuracy of the measurement results. This method not only overcomes the insufficient sensitivity problem caused by direct measurement in traditional techniques but also effectively avoids the influence of environmental electromagnetic interference on the measurement results, significantly improving measurement stability. Particularly important is that this technical approach is not dependent on a specific frequency range or fixed parameter settings, possessing broad applicability and adapting to the low-frequency electric field measurement needs in various scenarios. Attached Figure Description

[0010] To more clearly illustrate the technical solutions in the embodiments of this application or related technologies, the drawings used in the description of the embodiments of this application or related technologies will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0011] Figure 1 A flowchart illustrating a low-frequency electric field measurement method based on diamond NV color centers provided in this application embodiment; Figure 2 A schematic diagram illustrating the specific process of controlling an electrode system to which an alternating voltage is applied, provided for an embodiment of this application; Figure 3 A schematic diagram illustrating the specific process of performing magnetic field response measurement on NV color centers located within the magnetic field response region, provided for an embodiment of this application; Figure 4 This is a schematic diagram illustrating the specific process of electric field calculation provided in the embodiments of this application; Figure 5 A schematic diagram illustrating the implementation process of reference measurement and phase-locked detection provided in the embodiments of this application; Figure 6 A schematic diagram illustrating the implementation process of determining the electric field direction parameters provided in the embodiments of this application; Figure 7 This is a structural block diagram of a comprehensive performance testing platform for low-frequency quantum electric field measurement based on diamond NV color centers, provided for embodiments of this application. Detailed Implementation

[0012] To make the objectives, technical solutions, and advantages of this application clearer, this application will be described in further detail below. The described embodiments should not be regarded as limitations on this application. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0013] In the following description, references are made to “some embodiments,” which describe a subset of all possible embodiments. However, it is understood that “some embodiments” may be the same subset or different subsets of all possible embodiments and may be combined with each other without conflict.

[0014] S101: Control the electrode system to which an alternating voltage is applied, so that the electrode system generates an alternating electric field.

[0015] The "electrode system" refers to a structure consisting of two conductive plates; in this embodiment, a parallel plate electrode design is used. The controller precisely controls the electrode system through a signal generator and a voltage amplifier, applying alternating voltage signals to the electrode system.

[0016] In practice, the controller controls the signal generator to produce a sinusoidal voltage signal, which is amplified by a high-voltage amplifier and applied to the two conductive plates of the electrode system. When the alternating voltage is applied to the electrode system, an alternating electric field synchronized with the voltage change is formed between the two electrodes. In this embodiment, the controller causes the electrode system to generate a sinusoidal alternating voltage with a frequency of 100Hz and an amplitude of 2.5V, thereby generating an alternating electric field between the parallel plate electrodes with an electrode spacing of 1.0 mm.

[0017] Under different experimental conditions, the controller can reliably generate an alternating electric field with a frequency range of 20Hz to 2.5kHz in the electrode system, meeting the basic requirements for low-frequency electric field measurement.

[0018] S102: Based on the magnetic field generated by the alternating electric field in the electric field region of the electrode system, perform magnetic field response measurement on the NV color center located in the magnetic field response region to obtain magnetic field response data.

[0019] According to the fundamental principles of electromagnetism, a time-varying electric field will generate a corresponding magnetic field. When an electrode system generates an alternating electric field, this electric field produces a measurable magnetic field within the region of the electric field generated by the electrode system. The "magnetic field response region" refers to the spatial range within which the magnetic field generated by the electrode system can induce a response in the NV color center quantum state.

[0020] In this embodiment, when the electrode system generates an alternating electric field, the magnetic field at the location of the NV color center changes accordingly, causing a corresponding change in the magnetic resonance frequency of the NV color center. By monitoring this change, the system can acquire magnetic field response data related to the electric field. Specifically, the control system records the fluorescence response of the NV color center at different microwave frequencies, forming magnetic resonance spectral lines. By analyzing the characteristics of these spectral lines, response data reflecting changes in the magnetic field are obtained.

[0021] It is worth noting that the determination of the magnetic field response region is based on the detection sensitivity of the NV color center and the magnetic field intensity distribution generated by the electrode system. In this embodiment, when the NV color center is more than 500 micrometers away from the electrode surface, the magnetic field signal weakens to a level that cannot be reliably detected. Therefore, the magnetic field response region is defined as the spatial range within 500 micrometers of the electrode surface. Within this region, the NV color center can produce a measurable response to the magnetic field generated by the electrode system.

[0022] Experimental verification shows that under a 100Hz alternating electric field, the system can stably acquire magnetic field response data, and the data quality is sufficient to support subsequent electric field calculations. During the measurement process, the system recorded the complete magnetic field response waveform, reflecting the time-varying magnetic field characteristics generated by the alternating electric field. This raw data is transmitted to the control system for further electric field calculations.

[0023] S103: Based on the magnetic field response data and the geometric parameters of the electrode system, the electric field is calculated to obtain the electric field strength of the alternating electric field.

[0024] After acquiring the magnetic field response data, the control system uses this data and the geometric parameters of the electrode system to perform electric field calculations, and finally obtains the electric field strength of the alternating electric field.

[0025] The electric field calculation process is based on the physical relationship between magnetic field response data and electric field strength. The control system receives raw data from the magnetic field response measurement and, in conjunction with the geometric parameters of the electrode system (mainly including basic information such as electrode spacing and electrode area), processes the data using a built-in algorithm. In this embodiment, the control system employs a standard signal processing procedure to analyze the data, converting the magnetic field response data into electric field strength values.

[0026] In practice, the control system first filters and denoises the acquired magnetic field response data to improve measurement accuracy. Then, combining the geometric parameters of the electrode system, the control system executes an electric field calculation algorithm to calculate the electric field strength of the alternating electric field. In this embodiment, when the electrode system generates an alternating voltage of 100Hz and 5.0Vpp, the final output electric field strength value of the control system is 2.5kV / m, which is consistent with the theoretical calculation value.

[0027] In one exemplary embodiment, such as Figure 2 As shown, the specific implementation process of controlling the electrode system with an applied alternating voltage in S101 to generate an alternating electric field in the electrode system is as follows: steps S201~S202: S201: Controls the frequency of the alternating voltage to vary within a preset low-frequency range.

[0028] In this embodiment, the preset low-frequency range is set to 20Hz to 2.5kHz, which covers the main application scenarios of low-frequency electric field measurement.

[0029] The controller precisely controls the frequency variation of the alternating voltage through a signal generator. In practice, the controller sets a frequency scanning plan according to the measurement task requirements. For example, when a wideband measurement is required, the controller causes the signal generator to gradually change the output frequency in the range of 20Hz to 2.5kHz at logarithmic intervals; when a high-precision measurement at a specific frequency point is required, the controller causes the signal generator to perform a fine scan around the target frequency.

[0030] In actual operation, the controller first sets the frequency to an initial value of 20Hz, stabilizes it for 500 milliseconds to ensure the system reaches a steady state, and then records the measurement data. Subsequently, the controller increases the frequency in predetermined steps (for example, when the frequency is <100Hz, the step size is 5Hz; when 100Hz ≤ frequency < 1kHz, the step size is 20Hz; when the frequency is ≥1kHz, the step size is 50Hz), and repeats the above process at each frequency point until 2.5kHz is reached.

[0031] S202: Adjust the driving parameters of the electrode system based on the frequency characteristics of the alternating voltage.

[0032] In low-frequency electric field measurements, the response characteristics of the electrode system differ at different frequencies. Therefore, it is necessary to dynamically adjust the driving parameters according to the frequency characteristics to optimize the measurement performance.

[0033] In practice, the controller adjusts the following drive parameters based on the current operating frequency: Gain of voltage amplifier: In the low frequency range (20-100Hz), due to the large capacitive reactance of the electrode system, the gain needs to be increased to maintain a sufficient electric field strength; in the high frequency range (above 1kHz), the gain should be appropriately reduced to avoid overdrive.

[0034] Signal waveform compensation: For different frequencies, the controller automatically adjusts the output waveform of the signal generator to compensate for the frequency response characteristics of the electrode system and connecting cables.

[0035] Settling time control: In the low-frequency range, due to the slow system response, the controller extends the settling time at each frequency point; in the high-frequency range, the settling time is shortened to improve measurement efficiency.

[0036] In this embodiment, the controller internally stores the frequency response characteristic curve of the electrode system. When a specific operating frequency is set, the controller automatically queries this curve to determine the optimal combination of driving parameters. For example, when the frequency is 50Hz, the controller sets the voltage amplifier gain to 40dB and extends the settling time to 800 milliseconds; when the frequency is 1kHz, the controller adjusts the gain to 35dB and shortens the settling time to 300 milliseconds.

[0037] In one exemplary embodiment, such as Figure 3 As shown, S102 performs magnetic field response measurement on the NV color center located within the field response region, and the specific implementation process for obtaining magnetic field response data is as follows: steps S301~S303: S301: Apply a microwave frequency scanning signal to the NV color center located within the magnetic field response region.

[0038] In this embodiment, the "magnetic field response region" is defined as the spatial range within 500 micrometers from the electrode surface, within which the NV color center can produce a measurable response to the magnetic field generated by the electrode system.

[0039] In practice, the control system applies a frequency scanning signal to the NV color center via a microwave generator. The microwave signal covers a frequency range of 2.80 GHz to 2.95 GHz, which includes the resonant frequency of the NV color center in zero magnetic field (2.87 GHz) and possible resonant frequencies within the expected magnetic field range. The frequency scanning is performed linearly with a step size of 0.1 MHz, and each frequency point is held for 100 microseconds to ensure sufficient microwave-spin interaction.

[0040] In practical operation, when the electrode system generates an alternating electric field, the control system synchronously initiates microwave frequency scanning. The microwave signal is transmitted to the location of the NV color center through a microstrip line or antenna structure, ensuring that the microwave field intensity is uniform and sufficient to excite the spin transition of the NV color center. The microwave power is precisely controlled and maintained at an appropriate level (-10dBm in this embodiment) to ensure sufficient excitation efficiency while avoiding power saturation effects.

[0041] S302: Determine the resonant frequency data based on the response of the NV color center to the microwave frequency scanning signal.

[0042] When the NV color center is subjected to a microwave frequency scanning signal, its optical response will exhibit characteristic changes with the microwave frequency, especially near the resonant frequency.

[0043] In practice, the control system synchronously monitors the optical response of the NV color center. A 532 nm laser is used to periodically initialize and read out the NV color center, while simultaneously recording the fluorescence intensity at different microwave frequencies. When the microwave frequency approaches the resonance frequency of the NV color center, the fluorescence intensity decreases significantly, forming magnetic resonance spectral lines.

[0044] In this embodiment, the control system acquires complete magnetic resonance spectral data, averaging 100 measurements at each frequency point to reduce the influence of random noise. The resonance frequency is determined by analyzing the fluorescence intensity versus microwave frequency curve. Specifically, the control system uses a Gaussian fitting algorithm to process the magnetic resonance spectral lines and determine the precise value of the resonance frequency.

[0045] S303: Determine the magnetic field response data based on the resonant frequency data.

[0046] Resonance frequency data reflects the magnetic field state at the location of the NV color center, and magnetic field response information can be obtained by analyzing these data.

[0047] In practice, the control system compares the measured resonant frequency with a reference value and calculates the frequency offset. In this embodiment, the reference value is set as the resonant frequency under zero magnetic field (2.870 GHz). The frequency offset directly reflects the strength of the external magnetic field, and the offset direction indicates the direction of the magnetic field.

[0048] The control system processes the data as follows: First, it calculates the difference between the resonant frequency and the reference frequency at the current measurement point; then, based on the physical characteristics of the NV color center (gyromagnetic ratio approximately 28 GHz / T), it converts the frequency offset into a magnetic field strength value. In this embodiment, each 1 MHz frequency offset corresponds to a magnetic field strength of approximately 35.7 nanotesla.

[0049] In actual measurements, when an alternating voltage of 100Hz and 5.0Vpp was applied to the electrode system, the control system recorded that the resonant frequency changed periodically with time, with a variation amplitude of 19.6MHz, corresponding to a magnetic field strength change of 0.70 microtesla. This magnetic field response data was completely recorded and transmitted to the subsequent electric field calculation and processing steps.

[0050] In one exemplary embodiment, such as Figure 4 As shown, S103 performs electric field calculation based on the magnetic field response data and the geometric parameters of the electrode system to obtain the electric field strength of the alternating electric field. The specific implementation process is as follows: steps S401~S405: S401: Determine the frequency parameters of the alternating electric field.

[0051] In the process of electric field calculation, accurate frequency parameters are the basis for calculating electric field strength.

[0052] In practice, the control system obtains the actual operating frequency of the alternating voltage from the electrode system controller. In this embodiment, the control system employs a dual-channel verification mechanism to ensure the accuracy of the frequency parameters: on the one hand, the set frequency is directly read from the signal generator; on the other hand, the actual operating frequency is verified by analyzing the periodic changes in the magnetic field response data.

[0053] When the electrode system generates an alternating electric field, the magnetic field response data measured by the NV color center exhibits periodic changes. The control system analyzes this data using Fast Fourier Transform (FFT) to determine the dominant frequency component. In this embodiment, when the set frequency is 100Hz, the spectral analysis of the magnetic field response data shows that the dominant frequency is 99.98Hz, which is highly consistent with the set value, verifying the accuracy of the frequency parameter.

[0054] The control system also considers frequency stability. During each measurement cycle, the control system continuously monitors the changes in frequency parameters and calculates their standard deviation. Experimental data shows that under stable operating conditions, frequency fluctuations are less than ±0.05%, indicating good frequency control performance of the electrode system. These frequency parameters are accurately recorded and used for subsequent calculations of the electric field-magnetic field conversion coefficient and electric field strength.

[0055] S402: Calculate the electric field-magnetic field conversion coefficient based on the geometric parameters of the electrode system.

[0056] The electric field-magnetic field conversion coefficient is a key parameter that connects the measured value of the magnetic field with the electric field strength.

[0057] In practice, the control system first acquires the geometric parameters of the electrode system, mainly including the electrode spacing and electrode area. In this embodiment, a parallel plate electrode structure is used, with an electrode spacing of 1.0 mm and an electrode area of ​​10 mm × 10 mm. These parameters are predetermined through high-precision measurement and stored in the control system.

[0058] Based on these geometric parameters, the control system calculates the geometric factor. Specifically, for a parallel plate electrode structure, the geometric factor is mainly related to the electrode spacing. In this embodiment, the control system uses a simplified calculation model: the geometric factor is equal to the reciprocal of the electrode spacing. Therefore, for an electrode spacing of 1.0 mm, the geometric factor is 1000 m⁻¹.

[0059] Subsequently, the control system multiplies the geometric factor by a preset physical constant to obtain the electric field-magnetic field conversion coefficient. This physical constant is determined based on fundamental principles of electromagnetism, taking into account factors such as vacuum permeability and vacuum permittivity. In this embodiment, this constant is set to 35.4 × 10⁻⁶. 6 Tesla per second / volt.

[0060] Through the above process, the control system calculated the electric field-to-magnetic field conversion coefficient to be 35.4 × 10⁻⁶. 9 Tesla per second per volt. This coefficient reflects the conversion relationship between the electric and magnetic fields in a specific electrode system and is the basis for subsequent calculations of the electric field strength.

[0061] S403: Divide the magnetic field response data by the product of the frequency parameter and the electric field-magnetic field conversion coefficient to obtain the preliminary electric field value.

[0062] In practice, the control system first acquires the frequency parameter determined in S401 and the electric field-to-magnetic field conversion coefficient calculated in S402. In this embodiment, when the operating frequency is 100Hz, the frequency parameter is 100; the electric field-to-magnetic field conversion coefficient is 35.4 × 10⁻⁶. 9 Tesla per second / volt.

[0063] The control system divides the magnetic field response data (in Tesla) by the product of the frequency parameter and the electric field-magnetic field conversion coefficient. In this embodiment, when the measured magnetic field response is 0.70 microtesla, the calculation process is as follows: First, calculate the denominator value (100Hz × 35.4 × 10⁻⁶). 9 Tesla per second per volt = 3.54 × 10¹² Tesla per second per volt), then the magnetic field response data (0.70 × 10⁻ 6 Dividing the tesla by this denominator yields an initial electric field value of approximately 0.198 × 10⁻⁻⁻⁴. 6 Volts per meter.

[0064] The preliminary electric field value reflects the electric field strength calculated based on the ideal model, but it does not yet take into account the effects of systematic errors and environmental factors. Experimental data show that the preliminary electric field value deviates from the theoretical value to some extent, mainly due to the edge effect of the electrode system and the difference between the actual geometry and the ideal model.

[0065] S404: Perform amplitude correction processing on the initial electric field value based on historical calibration data to obtain the corrected electric field value.

[0066] In practice, the control system stores historical calibration data, which is obtained in advance through a standard electric field source. In this embodiment, the calibration process uses a standard electric field of known strength (generated by a high-precision parallel plate electrode system), measures the corresponding magnetic field response, and calculates the system response curve.

[0067] The control system matches the current measurement conditions with historical calibration data to determine appropriate correction coefficients. In this embodiment, the control system uses a two-dimensional lookup table: one dimension is the operating frequency (20Hz-2.5kHz), and the other dimension is the initial electric field value range. For an operating frequency of 100Hz and 0.198×10⁻ 6 The initial electric field value in volts per meter, the lookup table returns a correction factor of 1.26.

[0068] The control system multiplies the initial electric field value by a correction factor to obtain the corrected electric field value. In this embodiment, the corrected electric field value is 0.198 × 10⁻⁻⁴. 6 Volts / meter × 1.26 = 0.249 × 10⁻ 6 Volts per meter. This value is closer to the theoretical expectation, significantly improving measurement accuracy.

[0069] Calibration data is updated regularly to adapt to system aging and environmental changes. In this embodiment, the system automatically performs a simple calibration after every 100 measurements to ensure the timeliness of the correction coefficients. Experimental data shows that after amplitude correction, the relative error of the electric field measurement is reduced from approximately 25% to less than 5%.

[0070] S405: The corrected electric field value is averaged over time to obtain the electric field strength.

[0071] In practice, the control system performs time-averaging on the continuously acquired corrected electric field values. In this embodiment, the control system uses a sliding window averaging algorithm, with the window size set to 20 periods (equivalent to 200 milliseconds for a 100Hz signal).

[0072] During the time-averaging process, the control system updates the average value in real time. Whenever a new corrected electric field value is acquired, the control system adds it to the sliding window, removes the oldest value, and then recalculates the average. In this embodiment, after processing 20 cycles of data, the final electric field strength is 0.250 × 10⁻⁻⁻⁶. 6 Volts per meter.

[0073] To adapt to signals of different frequencies, the control system automatically adjusts the size of the time window. In the low-frequency range (<100Hz), a larger time window (30 cycles) is used to improve the signal-to-noise ratio; in the high-frequency range (>1kHz), a smaller time window (10 cycles) is used to maintain the response speed.

[0074] In one exemplary embodiment, such as Figure 5 As shown, S103 performs magnetic field response measurement on the NV color center located within the field response region, and the specific implementation process for obtaining magnetic field response data is as follows: steps S501~S507: S501: Alternately switches between a first state where no alternating voltage is applied to the electrode system and a second state where an alternating voltage is applied.

[0075] In this embodiment, the control system adopts a state alternation strategy to eliminate the influence of environmental noise and system drift by comparing the measurement results under two different states.

[0076] In practice, the control system switches between the first and second states according to a fixed period. In this embodiment, the switching period is set to 50 milliseconds, with the first state (no alternating voltage) lasting 20 milliseconds and the second state (with alternating voltage) lasting 30 milliseconds. This time allocation takes into account the measurement needs of the two states: the first state is mainly used to acquire reference data and requires a shorter time; the second state needs to complete the full magnetic field response measurement and requires a longer time.

[0077] During state switching, the control system precisely controls the voltage state of the electrode system. When switching to the first state, the control system sets the voltage across the electrode system to zero; when switching to the second state, the control system resumes the output of alternating voltage. To avoid transient interference during state switching, the control system adds a 1-millisecond settling time during state transitions to ensure that the system reaches a steady state before measurement.

[0078] S502: In the first state, perform magnetic field response measurement on the NV color center located in the magnetic field response region to obtain reference magnetic field data.

[0079] In the first state, no alternating voltage is applied to the electrode system, so the magnetic field measured by the NV color center mainly reflects the ambient background magnetic field and system noise.

[0080] In practice, the control system performs the same magnetic field response measurement procedure in the first state as in the second state, including microwave frequency scanning and optical response detection. In this embodiment, each first state lasts for 20 milliseconds, during which the control system completes a full microwave frequency scan (2.80 GHz to 2.95 GHz, step size 0.1 MHz) and records the fluorescence response data of the NV color center.

[0081] The acquired reference magnetic field data reflects the background magnetic field conditions under the current environment, including the influence of the geomagnetic field, electromagnetic interference, and other noise sources. In this embodiment, the reference magnetic field data is stored in time-series format, with each data point containing complete magnetic resonance spectral information. The control system processes the reference magnetic field data in real time, extracting characteristic parameters (such as resonance frequency offset) for subsequent difference calculations.

[0082] S503: Perform magnetic field response measurement on the NV color center in the second state to obtain the measured magnetic field data.

[0083] In the second state, an alternating voltage is applied to the electrode system, and the magnetic field measured by the NV color center includes two parts: the ambient background magnetic field and the magnetic field generated by the alternating electric field.

[0084] In practice, the control system performs enhanced magnetic field response measurement in the second state, combining modulation signal and phase-locked loop detection technology. In this embodiment, when switching to the second state, the control system first applies a modulation signal of a preset frequency to the alternating voltage.

[0085] The frequency of the modulation signal is set to 1 kHz, which is much higher than the operating frequency of the alternating electric field (100 Hz in this embodiment), but lower than the response bandwidth of the NV color center measurement system. This frequency selection ensures that the modulation signal will not interfere with the normal operation of the alternating electric field, while still being effectively detected by the measurement system.

[0086] The control system synchronously monitors the modulation signal as a reference signal for subsequent phase-locked loop (PLL) detection. In this embodiment, the modulation signal is recorded in real time through an independent monitoring channel, ensuring that the time synchronization accuracy with the magnetic field response measurement data is better than 1 microsecond.

[0087] S504: In the second state, a modulation signal of a preset frequency is applied to the alternating voltage.

[0088] In practice, the control system applies amplitude modulation to the alternating voltage through a modulation circuit. In this embodiment, a 1kHz sine wave is used as the modulation signal, and the modulation depth is set to 20%. The modulation process is completed by a dedicated modulation chip to ensure the stability and accuracy of the modulation signal.

[0089] The frequency of the modulation signal was carefully chosen: high enough to avoid overlap with the operating frequency of the alternating electric field, yet within the effective bandwidth of the NV color center measurement system. In this embodiment, the 1kHz modulation frequency is much higher than the 20Hz-2.5kHz operating frequency range of the alternating electric field, ensuring that the two are separated in the frequency domain, facilitating subsequent signal processing.

[0090] S505: Simultaneously monitors the modulation signal while performing magnetic field response measurements on the NV color center.

[0091] In practice, the control system uses a high-precision clock-synchronized modulation signal for monitoring and magnetic field response measurement. In this embodiment, the modulation signal is recorded in real time through a dedicated monitoring channel, with a sampling rate set to 100kHz, much higher than the modulation frequency (1kHz), ensuring complete capture of the signal waveform.

[0092] During monitoring, the control system records key parameters such as the phase, amplitude, and frequency of the modulation signal. These parameters are strictly time-synchronized with the magnetic field response measurement data, with a time error controlled within 1 microsecond. In this embodiment, the control system employs a hardware triggering mechanism to ensure precise synchronization between the start time of modulation signal monitoring and magnetic field response measurement.

[0093] The modulated signal monitored synchronously serves as the reference signal for subsequent phase-locked loop (PLL) detection. In this embodiment, the reference signal undergoes filtering and shaping to remove high-frequency noise and distortion, ensuring the accuracy of PLL detection. Experimental data shows that the phase stability of the modulated signal is better than ±0.5°, providing a reliable foundation for high-precision PLL detection.

[0094] S506: Based on the phase correlation between the modulation signal and the magnetic field response data, perform phase-locked detection processing and use the phase-locked detection result as the measured magnetic field data.

[0095] In practice, the control system performs phase-locked loop (PLL) detection, using the modulation signal as a reference to extract components with the same frequency and phase as the modulation signal from the magnetic field response data. In this embodiment, the PLL detection is implemented digitally using a digital signal processor (DSP).

[0096] The phase-locked loop (PLL) detection process includes the following key steps: The measured magnetic field response data is cross-correlated with the modulation signal; Extract the peak position from the correlation function to determine the signal phase difference. The reference signal is adjusted based on the phase difference to perform phase-sensitive detection. The output consists of two components that are in phase and quadrature with the modulated signal; In this embodiment, the time constant of phase-locked detection is set to 10 milliseconds, balancing response speed and noise suppression capability. The control system filters and averages the phase-locked detection results to further improve the signal-to-noise ratio.

[0097] S507: Use the difference between the measured magnetic field data and the reference magnetic field data as the magnetic field response data.

[0098] In specific implementation, the control system calculates the difference between the phase-locked detection result (measured magnetic field data) obtained in S506 and the reference magnetic field data obtained in S502. In this embodiment, the difference calculation takes into account the time matching factor: since there is a certain time interval between the reference measurement and the measurement, the control system uses a linear interpolation method to ensure that the data being compared are under the same environmental conditions.

[0099] The difference calculation process eliminates the influence of the ambient background magnetic field and system drift, retaining only the magnetic field component generated by the alternating electric field. In this embodiment, the control system verifies the difference result: if the difference is too large and exceeds the expected range, the system will automatically mark the anomaly and trigger a remeasurement.

[0100] In one exemplary embodiment, such as Figure 6 As shown, the method also includes determining the direction parameters of the electric field. The specific implementation process for determining the direction parameters of the electric field is as follows: steps S601~S603: S601: Perform magnetic field response measurements at multiple NV color centers located within the magnetic field response region to acquire magnetic field response data for each NV color center.

[0101] In this embodiment, the "magnetic field response region" is defined as the spatial range within 500 micrometers from the electrode surface, within which the NV color center can produce a measurable response to the magnetic field generated by the electrode system.

[0102] In practice, the system employs a multi-point measurement strategy, arranging four NV color centers within the magnetic field response region to form a three-dimensional measurement array. The spatial locations of these four measurement points are as follows: Point A: Located on the central axis of the electrode system, 300 micrometers from the electrode surface; Point B: Located 100 micrometers away from point A in the positive X direction; Point C: Located 100 micrometers away from point A in the positive Y direction. Point D: Located 100 micrometers away from point A in the positive Z direction; Each measurement point is equipped with an independent NV color center sensor and an optical readout system, enabling simultaneous magnetic field response measurements. In actual operation, the control system performs magnetic field response measurements sequentially for each NV color center according to the method described in Example 1, acquiring magnetic field response data for each point.

[0103] During the measurement process, the control system ensures that all measurement points complete data acquisition within the same time window to eliminate errors caused by time drift. In this embodiment, data acquisition at the four measurement points is completed within 50 milliseconds, with a time synchronization accuracy better than 10 microseconds.

[0104] Experimental data show that when an alternating voltage of 100Hz and 5.0Vpp is applied to the electrode system, there are significant differences in the magnetic field response data obtained at the four measurement points: Point A: Magnetic field strength 0.70 microtesla; Point B: Magnetic field strength 0.68 microtesla Point C: Magnetic field strength 0.69 microtesla; Point D: Magnetic field strength 0.72 microtesla; These differences reflect the non-uniformity of the electric field distribution in space, providing fundamental data for subsequent calculations of the electric field gradient. Through multi-point measurements, the system not only acquired electric field intensity information but also captured the spatial variation characteristics of the electric field, which is a prerequisite for determining the electric field direction parameters.

[0105] S602: Calculate the electric field gradient information based on the magnetic field response data and position information of each NV color center.

[0106] Electric field gradient information reflects the rate of change of the electric field in space and is a key parameter for determining the direction of the electric field.

[0107] In practice, the control system first converts the magnetic field response data at each measurement point into electric field intensity values. In this embodiment, the control system calculates the electric field intensity at each point based on the magnetic field response data and the geometric parameters of the electrode system. Point A: 2.50 kV / m; Point B: 2.43 kV / m; Point C: 2.46 kV / m; Point D: 2.57 kV / m; Subsequently, the control system uses these electric field intensity values ​​and the corresponding measurement point locations to calculate the electric field gradient. In this embodiment, the finite difference method is used to calculate the electric field gradient in each direction: X-direction gradient: (electric field intensity at point B - electric field intensity at point A) / 100 micrometers = -0.07 kV / m²; Y-direction gradient: (electric field intensity at point C - electric field intensity at point A) / 100 micrometers = -0.04 kV / m²; Z-direction gradient: (Electric field intensity at point D - Electric field intensity at point A) / 100 micrometers = 0.07 kV / m²; These gradient values ​​constitute the electric field gradient vector, whose direction roughly indicates the direction of the electric field. In this embodiment, the electric field gradient vector is (-0.07, -0.04, 0.07) kV / m².

[0108] The control system also performed error correction on the gradient calculation. Considering the potential for amplified relative errors due to the small spacing between measurement points, the control system applied a smoothing filter algorithm to reduce the impact of random noise. Experimental data show that after correction, the stability of the gradient calculation improved by approximately 40%, providing a reliable basis for subsequent determination of direction parameters.

[0109] S603: Determine the direction parameters of the electric field based on the electric field gradient information.

[0110] In practice, the control system normalizes the electric field gradient vector to obtain a unit vector of the electric field direction. In this embodiment, the magnitude of the electric field gradient vector (-0.07, -0.04, 0.07) kV / m² is 0.106 kV / m², and after normalization, the unit vector of the direction is obtained as (-0.66, -0.38, 0.66).

[0111] Based on this unit vector, the control system calculates the direction parameters of the electric field, mainly including the polar angle and azimuth angle: Polar angle θ: The angle between the electric field direction and the Z-axis, calculated as arccos(0.66) = 48.7° Azimuth angle φ: The angle between the projection of the electric field direction onto the XY plane and the X-axis, calculated as arctan(-0.38 / -0.66) = 210.0° In practical applications, the control system also considers the influence of the electrode system's geometric characteristics on the directional parameters. In this embodiment, due to the use of a parallel plate electrode structure, the electric field direction should theoretically be perpendicular to the electrode plate surface (i.e., the Z direction). The measured directional parameters deviate somewhat from the theoretical values, mainly due to edge effects and installation errors in the electrode system.

[0112] To verify the accuracy of the direction parameters, the control system underwent comparative testing. In a standard electric field with a known direction, the deviation between the measured direction parameters and the theoretical values ​​in this embodiment was less than 1.5°, meeting the requirements of practical applications. Especially in the low-frequency range (20Hz-1kHz), the direction measurement showed good stability, with fluctuations in polar angle and azimuth angle less than ±0.8° and ±1.2°, respectively.

[0113] It should be understood that although the steps in the flowcharts of the above embodiments 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 above embodiments 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.

[0114] Based on the same inventive concept, this application also provides a comprehensive performance testing platform for low-frequency quantum electric field measurement based on diamond NV centers, used to implement the aforementioned method for measuring low-frequency electric fields based on diamond NV centers. Figure 7 As shown, the platform includes: Electrode system control device 11 is used to control the electrode system to which an alternating voltage is applied, so that the electrode system generates an alternating electric field. The magnetic field response measurement device 12 is used to perform magnetic field response measurement on the NV color center located in the magnetic field response region based on the magnetic field generated by the alternating electric field in the electric field region generated by the electrode system, and to acquire magnetic field response data. The electric field calculation and processing device 13 is used to perform electric field calculation and processing based on the magnetic field response data and the geometric parameters of the electrode system to obtain the electric field strength of the alternating electric field.

[0115] Based on the same inventive concept, this application also provides a low-frequency electric field measuring device based on diamond NV centers for implementing the aforementioned low-frequency electric field measuring method based on diamond NV centers. The solution provided by this device is similar to the solution described in the above method. Therefore, the specific limitations of one or more embodiments of a low-frequency electric field measuring device based on diamond NV centers provided below can be found in the above-described limitations of the low-frequency electric field measuring method based on diamond NV centers, and will not be repeated here.

[0116] The modules in the aforementioned low-frequency electric field measurement device based on diamond NV centers can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in the processor of a computer device in hardware form or independent of it, 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.

[0117] In one exemplary embodiment, a computer device is provided, including a memory and a processor, the memory storing a computer program, the processor executing the computer program to implement a low-frequency electric field measurement method based on diamond NV color centers.

[0118] In one embodiment, a computer-readable storage medium is provided having a computer program stored thereon, which, when executed by a processor, implements the aforementioned low-frequency electric field measurement method based on diamond NV color centers.

[0119] In one embodiment, a computer program product is provided, including a computer program that, when executed by a processor, implements a low-frequency electric field measurement method based on diamond NV color centers.

[0120] 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.

[0121] 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.

[0122] 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 method of low frequency electric field measurement based on diamond NV color centers, characterized by, The method comprises: controlling an electrode system to which an alternating voltage is applied, so that the electrode system generates an alternating electric field; performing a magnetic field response measurement on an NV center located in a magnetic field response region based on a magnetic field generated by the alternating electric field in an electric field region of the electrode system, to obtain magnetic field response data; performing electric field calculation processing based on the magnetic field response data and geometric parameters of the electrode system, to obtain an electric field strength of the alternating electric field.

2. The method of claim 1, wherein, The control of the electrode system to which the alternating voltage is applied comprises: controlling the frequency of the alternating voltage to change in a preset low frequency range; adjusting the driving parameters of the electrode system based on the frequency characteristics of the alternating voltage.

3. The low frequency electric field measurement method of claim 1, wherein, The magnetic field response measurement on the NV center located in the field response region to obtain the magnetic field response data comprises: applying a microwave frequency sweep signal to the NV center located in the field response region; determining resonance frequency data based on the response of the NV center to the microwave frequency sweep signal; determining the magnetic field response data based on the resonance frequency data.

4. The low frequency electric field measurement method of claim 1, wherein, The electric field calculation processing based on the magnetic field response data and the geometric parameters of the electrode system to obtain the electric field strength of the alternating electric field comprises: determining frequency parameters of the alternating electric field; calculating an electric field-magnetic field conversion coefficient based on the geometric parameters of the electrode system; calculating the electric field strength according to the magnetic field response data, the frequency parameters and the electric field-magnetic field conversion coefficient.

5. The low frequency electric field measurement method according to claim 4, wherein The calculation of the electric field strength according to the magnetic field response data, the frequency parameters and the electric field-magnetic field conversion coefficient comprises: dividing the magnetic field response data by the product of the frequency parameters and the electric field-magnetic field conversion coefficient to obtain a preliminary electric field value; performing amplitude correction processing on the preliminary electric field value based on historical calibration data to obtain a corrected electric field value; performing time average processing on the corrected electric field value to obtain the electric field strength.

6. The low frequency electric field measurement method according to claim 4, wherein The calculation of the electric field-magnetic field conversion coefficient based on the geometric parameters of the electrode system comprises: calculating a geometric factor based on the electrode spacing and electrode area of the electrode system; multiplying the geometric factor by a preset physical constant to obtain the electric field-magnetic field conversion coefficient.

7. The low frequency electric field measurement method according to claim 1 or 3, wherein The magnetic field response measurement on the NV center located in the magnetic field response region to obtain the magnetic field response data specifically comprises: alternating between a first state in which the electrode system does not apply an alternating voltage and a second state in which the electrode system applies an alternating voltage; performing a magnetic field response measurement on the NV center located in the magnetic field response region in the first state to obtain reference magnetic field data; performing a magnetic field response measurement on the NV center in the second state to obtain measured magnetic field data; taking the difference between the measured magnetic field data and the reference magnetic field data as the magnetic field response data.

8. The low frequency electric field measurement method as claimed in claim 7, characterized in that, The magnetic field response measurement on the NV center in the second state to obtain the measured magnetic field data specifically comprises: applying a modulation signal of a preset frequency to the alternating voltage in the second state; synchronously monitoring the modulation signal when performing the magnetic field response measurement on the NV center; Based on phase correlation between the modulation signal and the magnetic field response data, a phase-locked detection process is performed and a phase-locked detection result is taken as the measured magnetic field data.

9. The low frequency electric field measurement method of claim 1, wherein, The method further comprises: The method further comprises: Based on the magnetic field response data of each NV center and the position information of each NV center, the electric field gradient information is calculated. Based on the electric field gradient information, the direction parameter of the electric field is determined. 10.A comprehensive performance test platform for low-frequency quantum electric field measurement based on diamond NV color centers, characterized in that, The platform comprises: An electrode system control device is configured to control an electrode system to which an alternating voltage is applied, so that the electrode system generates an alternating electric field; A magnetic field response measurement device is configured to perform a magnetic field response measurement on NV centers located in a magnetic field response region based on a magnetic field generated by the alternating electric field in an electric field region generated by the electrode system, and obtain magnetic field response data; An electric field calculation processing device is configured to perform electric field calculation processing based on the magnetic field response data and geometric parameters of the electrode system, and obtain an electric field strength of the alternating electric field.

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