Current measurement method based on quantum technology

Abstract

A current measurement method based on a quantum technology judges the range of formant appearance after current change of a measured wire through a frequency sweep result based on feature points, adaptively locks microwave frequency for frequency sweep, reduces the time cost of the frequency sweep process, greatly compresses the microwave frequency sweep time, and improves the measurement accuracy. The quantum state signal extraction speed can be remarkably improved while the relative high sensitivity is kept, non-contact real-time current measurement is achieved, and the method is characterized by comprising the steps that an atom source is close to a measured wire to couple a magnetic field signal generated by current in the measured wire; the atomic quantum state control system of the atomic source is connected with an upper computer through an electrical integration module, based on the optical detection magnetic resonance technology, in the measurement process, feature points are selected near formants of optical detection magnetic resonance for frequency sweeping, the positions of the feature points are updated in a self-adaptive mode based on the frequency sweeping result of the feature points, and the measurement accuracy is improved. A microwave signal frequency band is adaptively matched with a formant, a current measurement value is obtained, global frequency sweeping is replaced by feature point frequency sweeping, and the measurement speed is increased.

Description

Technical Field

[0001] This invention relates to the field of quantum precision measurement technology, and in particular to a current measurement method based on quantum technology. Background Technology

[0002] In the 1990s, scientists discovered the unique energy level structure of diamond NV (nitrogen-vacancy) color centers. Benefiting from their stability and long coherence time, NV color centers are widely used in quantum precision measurement of magnetic fields. The ultra-high sensitivity of NV color centers to magnetic fields, combined with the correspondence of electromagnetic induction, has led scientists to gradually apply them to non-contact indirect current measurement, which aligns perfectly with the current measurement needs of fields such as new energy vehicles, microelectronic devices, and power systems. Traditional methods for current detection mainly include in-circuit measurement and flux measurement. In-circuit measurement requires adding a detection circuit (such as a multimeter) to the circuit, but this method is difficult to use when the device is packaged for protection. Flux measurement relies on current changes for detection, and the resulting measurement error accumulation leads to low accuracy. Quantum precision measurement technology based on NV color centers offers advantages such as high sensitivity, miniaturization, operation at room temperature, and no measurement error accumulation. Current quantum current measurement schemes based on diamond color centers calculate the current using ODMR (Optically Detected Magnetic Resonance) obtained through wide-field scanning. However, the process of obtaining results through frequency sweeping takes several minutes, and the mismatch between the rate of current change and the rate of quantum state signal extraction makes existing methods difficult to meet the real-time current monitoring requirements of the aforementioned application scenarios. Besides NV color centers in diamond, color centers in many other materials (such as SiC) also possess similar properties. Summary of the Invention

[0003] This invention addresses the deficiencies or shortcomings of existing technologies by providing a current measurement method based on quantum technology. By analyzing the frequency sweep results based on feature points using a microwave matching adaptive algorithm, the range of resonance peaks after changes in the current of the measured conductor is determined. The microwave frequency is then adaptively locked for frequency sweeping, reducing the time cost of the frequency sweeping process and significantly compressing the microwave frequency sweeping time. This method can significantly improve the quantum state signal extraction speed while maintaining relatively high sensitivity, thus achieving non-contact real-time current measurement.

[0004] The technical solution of the present invention is as follows:

[0005] A current measurement method based on quantum technology is characterized by including bringing an atomic source close to the conductor under test to couple the magnetic field signal generated by the current in the conductor. The atomic quantum state manipulation system of the atomic source is connected to a host computer through an electrical integrated module. Based on optically detected magnetic resonance (OMR) technology, during the measurement process, feature points are selected near the resonance peak of OMR for frequency sweeping. The feature point positions are adaptively updated based on the feature point frequency sweep results, so that the microwave signal frequency band adaptively matches the resonance peak and obtains the current measurement value. By using feature point frequency sweeping instead of global frequency sweeping, the measurement speed is improved.

[0006] The atomic source is a diamond NV color center. The atomic quantum state manipulation system includes an acousto-optic modulator connected to the diamond NV color center. The acousto-optic modulator is connected to a laser. The diamond NV color center is connected to a microwave module in an electrical integrated module via a microwave amplifier and a microwave switch. The diamond NV color center is connected to a data acquisition module in the electrical integrated module via a photoelectric converter. The acousto-optic modulator and the microwave switch are respectively connected to a timing pulse module in the electrical integrated module. The data acquisition module, the microwave module, and the timing pulse module are all connected to the host computer via an FPGA module. The magnetic field generated by the current in the tested wire and the coupling effect of the laser and microwave cause the diamond NV color center to undergo a corresponding fluorescence change. The generated fluorescence is converted into an electrical signal by the photoelectric converter and collected by the data acquisition module.

[0007] Includes the following steps:

[0008] Step 1: Perform a microwave frequency sweep and fluorescence detection covering the entire measurement range, and plot the ODMR curve;

[0009] Step 2: Based on the mathematical model, fit the ODMR curve and extract the NV color center quantum state signal;

[0010] Step 3: Based on the fitted curve, select several observation points in the resonance peak region as feature points (equidistant points are recommended, but non-equidistant points are also acceptable).

[0011] Step 4: Perform a new round of microwave frequency sweep and fluorescence detection only on the feature points;

[0012] Step 5: Based on the offset estimation algorithm, the offset direction and distance of the resonance peak are calculated using the two detection results of the feature points. The new resonance peak curve is obtained by fitting the offset information, the NV color center quantum state signal is extracted, and new feature points are selected.

[0013] Step 6: Repeat steps 4 and 5 until a new resonance peak is locked, then return to step 3.

[0014] The mathematical model in step 2 is expressed as follows:

[0015] ,

[0016] In the formula, y is the measured current, n represents the number of resonance peaks, and j is the sequence number. Let represent the amplitude of the j-th resonance peak, e be the natural constant, and x be the microwave sweep frequency. The x-coordinate of the vertex of the j-th resonance peak is represented by the x-coordinate of the vertex of the j denoted by , represents the half-height and half-width of the j-th resonance peak, and m represents the offset of the j-th resonance peak on the vertical axis.

[0017] Step 3 includes the following expression:

[0018] ,

[0019] in It represents the x-coordinate of the i-th feature point. is the number of feature points selected for each resonance peak, l is the distance in the x-direction between adjacent feature points, and N is a natural number.

[0020] Step 5 includes the following expression:

[0021] ,

[0022] ,

[0023] in It is the offset direction of the value in the i-th position of the sequence. It is the measured value of the i-th characteristic point after the current changes. It is the measured value of the i-th characteristic point before the current change. It is the resonance peak shift distance. yes x-coordinate yes x-coordinate It is the measured value at any characteristic point after the current changes. It represents any feature point.

[0024] The technical effects of this invention are as follows: This invention provides a current measurement method based on quantum technology, which can perform microwave matching adaptive algorithm analysis based on the frequency sweep results of feature points, accurately determine the range of resonance peaks after current changes, adaptively lock the microwave frequency for frequency sweeping, reduce the time cost of the frequency sweeping process while maintaining a certain level of accuracy, and significantly compress the microwave frequency sweeping time, providing a reliable solution for real-time current measurement based on diamond color centers. Attached Figure Description

[0025] Figure 1This is a schematic diagram of the system structure involved in implementing the quantum technology-based current measurement method of the present invention.

[0026] Figure 2 yes Figure 1 A schematic diagram of the composition of the integrated module of China Electronics Technology Group Corporation (CETC).

[0027] Figure 3 This is a schematic diagram of the process of implementing a current measurement method based on quantum technology according to the present invention. Figure 3 The process includes: Step 1, wide-field frequency sweep (global frequency sweep); Step 2, selecting feature points based on resonance peaks; Step 3, sweeping the feature points after current change; Step 4, judging the offset properties; if the resonance peak is nearby, jump to Step 5, otherwise return to Step 1; Step 5, apply the offset estimation algorithm; Step 6, lock the new resonance peak, and then return to Step 2.

[0028] Figure 4 A schematic diagram of the scheme for selecting characteristic points for a single resonance peak.

[0029] The reference numerals in the attached diagram are listed below: 1-Test lead wire; 2-Laser; 3-Acousto-optic modulator; 4-Diamond sample; 5-Photoelectric converter; 6-Electrical integrated module; 7-Microwave amplifier; 8-Microwave switch; 9-Host computer; 601-FPGA module (FPGA, Field Programmable Gate Array); 602-Data acquisition module; 603-Timing pulse module; 604-Microwave module; 605-Input / output interface; 606-Physical interface. Detailed Implementation

[0030] The following is in conjunction with the attached diagram ( Figures 1-4 The present invention will be described below.

[0031] Figure 1 This is a schematic diagram of the system structure involved in implementing the quantum technology-based current measurement method of the present invention. Figure 2 yes Figure 1 A schematic diagram of the composition of the integrated module of China Electronics Technology Group Corporation (CETC). Figure 3 This is a schematic diagram of the process of implementing a current measurement method based on quantum technology according to the present invention. Figure 4 A schematic diagram illustrating the selection scheme for characteristic points of a single resonance peak. (Reference) Figures 1 to 4As shown, a current measurement method based on quantum technology includes bringing an atomic source (e.g., diamond sample 4) close to the test wire 1 to couple the magnetic field signal generated by the current in the test wire 1. The atomic quantum state manipulation system of the atomic source is connected to a host computer 9 through an electrical integration module 6. Based on optically detected magnetic resonance (OMR) technology, during the measurement process, feature points are selected near the resonance peak of the OMR for frequency sweeping. The feature point positions are adaptively updated based on the feature point frequency sweeping results, so that the microwave signal frequency band adaptively matches the resonance peak and obtains the current measurement value. By using feature point frequency sweeping instead of global frequency sweeping, the measurement speed is improved. The atomic source is a diamond NV color center. The atomic quantum state manipulation system includes an acousto-optic modulator 3 connected to the diamond NV color center (i.e., diamond sample 4). The acousto-optic modulator 3 is connected to a laser 2. The diamond NV color center is connected to a microwave module 604 in an electrical integrated module 6 via a microwave amplifier 7 and a microwave switch 8. The diamond NV color center is connected to a data acquisition module 602 in an electrical integrated module 6 via a photoelectric converter 5. The acousto-optic modulator 3 and the microwave switch 8 are respectively connected to a timing pulse module 603 in an electrical integrated module 6. The data acquisition module 602, the microwave module 604, and the timing pulse module 603 are all connected to the host computer 9 via an FPGA module 601. The magnetic field generated by the current in the tested lead wire 1 and the coupling effect of the laser and microwave cause the diamond NV color center to undergo a corresponding fluorescence change. The generated fluorescence is converted into an electrical signal by the photoelectric converter 5 and collected by the data acquisition module 602.

[0032] A current measurement method based on quantum technology includes the following steps: Step 1, performing a microwave frequency sweep and fluorescence detection covering the entire measurement range, and plotting the ODMR curve; Step 2, fitting the ODMR curve based on a mathematical model, and extracting the NV center quantum state signal; Step 3, selecting several observation points in the resonance peak region as feature points based on the fitted curve (equidistant is recommended, but non-equidistant is also acceptable); Step 4, performing a new round of microwave frequency sweep and fluorescence detection only on the feature points; Step 5, using the offset estimation algorithm, calculating the offset direction and distance of the resonance peak using the two detection results of the feature points, fitting a new resonance peak curve with the offset information, extracting the NV center quantum state signal, and selecting new feature points; Step 6, repeating steps 4 and 5 until a new resonance peak is locked, then returning to step 3.

[0033] The mathematical model in step 2 is expressed as follows:

[0034] ,

[0035] In the formula, y is the measured current, n represents the number of resonance peaks, and j is the sequence number. Let represent the amplitude of the j-th resonance peak, e be the natural constant, and x be the microwave sweep frequency. The x-coordinate of the vertex of the j-th resonance peak is represented by the x-coordinate of the vertex of the j denoted by , represents the half-height and half-width of the j-th resonance peak, and m represents the offset of the j-th resonance peak on the vertical axis.

[0036] Step 3 includes the following expression:

[0037] ,

[0038] in It represents the x-coordinate of the i-th feature point. is the number of feature points selected for each resonance peak, l is the distance in the x-direction between adjacent feature points, and N is a natural number.

[0039] Step 5 includes the following expression:

[0040] ,

[0041] ,

[0042] in It is the offset direction of the value in the i-th position of the sequence. It is the measured value of the i-th characteristic point after the current changes. It is the measured value of the i-th characteristic point before the current change. It is the resonance peak shift distance. yes x-coordinate yes x-coordinate It is the measured value at any characteristic point after the current changes. It represents any feature point.

[0043] This invention addresses the mismatch between the quantum state signal extraction speed and the current change rate in current quantum current measurements using diamond. It provides a quantum technology-based current measurement method by reducing the number of frequency sweep points and adaptively selecting a specific microwave frequency for the next sweep using the proposed measurement method, thereby calculating the measured current in real time. The measurement system includes a laser, an acousto-optic modulator, a diamond sample, a photoelectric converter, an electrical integrated system, a microwave amplifier, a microwave switch, and a host computer. The measurement method provided by this invention can significantly improve the quantum state signal extraction speed while maintaining relatively high sensitivity, which has significant application value for improving the real-time performance of diamond color center quantum measurement systems.

[0044] refer to Figures 1 to 4As shown, a current measurement method based on quantum technology includes an atomic source (including but not limited to diamond NV color centers), an atomic quantum state manipulation system (including but not limited to lasers, acousto-optic modulators, microwave amplifiers, and microwave switches), and other auxiliary systems (including but not limited to photoelectric converters, electrical systems, and host computers).

[0045] The aforementioned quantum technology-based current measurement method uses optically detected magnetic resonance (OMR) technology. During the measurement process, a small number of feature points are selected near the resonance peak of the OMR for frequency sweeping. The feature point positions are adaptively updated based on the feature point frequency sweeping results, so that the microwave signal frequency band adaptively matches the resonance peak and obtains the current measurement value. By using feature point frequency sweeping instead of global frequency sweeping, the measurement speed is improved.

[0046] The quantum technology-based current measurement method includes the following steps:

[0047] Step 1: Perform a microwave frequency sweep and fluorescence detection covering the entire measurement range, and plot the ODMR curve;

[0048] Step 2: Based on the mathematical model, fit the ODMR curve with data and extract the NV color center quantum state signal;

[0049] Step 3: Based on the fitted curve, select several observation points in the resonance peak region as feature points according to the properties of the feature points (equidistant points are recommended, but non-equidistant points are also acceptable).

[0050] Step 4: Perform a new round of microwave frequency sweep and fluorescence detection only on the feature points;

[0051] Step 5: Based on the offset estimation algorithm, the offset direction and distance of the resonance peak are calculated using the two detection results of the feature points. The new resonance peak curve is obtained by fitting the offset information, the NV color center quantum state signal is extracted, and new feature points are selected.

[0052] Step 6: Repeat steps 4 and 5.

[0053] The mathematical model for the quantum technology-based current measurement method is determined by the following formula:

[0054]

[0055] In the formula, n represents the number of resonance peaks. Represents the amplitude of the j-th resonance peak. The x-coordinate of the vertex of the j-th resonance peak is represented by the x-coordinate of the vertex of the j denoted by , represents the half-height and half-width of the j-th resonance peak, and m represents the offset of the j-th resonance peak on the vertical axis.

[0056] The aforementioned quantum technology-based current measurement method uses a feature point that possesses the following properties: it can reflect information about the entire ODMR spectrum; its positional distribution is universal for curves with the same mathematical model; and it has a certain degree of tolerance for measurement errors.

[0057] The aforementioned quantum technology-based current measurement method uses the following formula to determine the characteristic points: for a single resonance peak, a specific frequency point (e.g., when the atomic source is the diamond NV color center, a frequency point of 2870 MHz is selected), the peak vertex, and three pairs of points symmetrical about the peak are selected as characteristic points.

[0058] ,

[0059] in is the x-coordinate of the i-th feature point, l is the distance in the x-direction between adjacent feature points, and N is a natural number.

[0060] The quantum technology-based current measurement method, specifically the offset estimation algorithm, infers the offset direction and distance by utilizing the changes in measured values ​​of feature points before and after a current change, thereby pinpointing the new resonance peak location. The offset direction is determined by detecting changes in the values ​​of a seven-bit sequence, with each bit in the sequence determined using the following formula:

[0061]

[0062] In the formula This represents the measured value at the i-th feature point before the current change. This represents the measured value of the i-th feature point after the current change;

[0063] The offset distance is determined by the following formula:

[0064]

[0065]

[0066] In the formula Indicates the resonance peak shift distance. Indicates the corresponding measured value x-coordinate Indicates the corresponding measured value The x-coordinate.

[0067] This invention relates to a current measurement method based on quantum technology. Compared with conventional measurement methods, this method significantly improves measurement speed while maintaining measurement accuracy. The method abandons the previous global frequency sweep approach, instead selecting a small number of feature points near each resonance peak for frequency sweeping, thereby increasing measurement speed. This invention falls within the field of quantum precision measurement and has significant application value for non-contact real-time current measurement.

[0068] refer to Figure 1 As shown, a current measurement method based on quantum technology includes a system comprising a test conductor 1, a laser 2, an acousto-optic modulator 3, a diamond sample 4, a photoelectric converter 5, an electrical integrated system 6, a microwave amplifier 7, a microwave switch 8, and a host computer 9. The photoelectric converter 5, the microwave switch 8, the acousto-optic modulator 3, and the host computer 9 are connected to the electrical integrated system 6 via a connecting device, and the microwave amplifier 7 is connected to the microwave switch 8 via a connecting device. The connecting device is a cable. The laser 2 emits a light source with a wavelength of 532 nm. The magnetic field generated by the current flowing through the test conductor 1, coupled with the laser and microwave, causes a corresponding fluorescence change in the diamond sample 4. The host computer 9 is used to set experimental parameters, receive and process results, and generate graphs. The fluorescence generated by the diamond sample 4 reaches the photodetector 5, is converted into an electrical signal, and transmitted to the electrical integrated system 6 via the connecting device.

[0069] refer to Figure 2 As shown, the electrical integrated system 6 includes an FPGA module 601, a microwave module 604, a data acquisition module 602, and a timing pulse module 603. The electrical integrated system 6 is connected to other instruments and equipment via an input / output interface 605, and its internal modules are connected via physical interfaces 606. The FPGA module 601 receives parameters from the host computer 9 and generates corresponding signals, which are output to the timing pulse module 603 and the microwave module 604. It also receives signals from the data acquisition module 603, processes the data, and outputs it to the host computer 9. The microwave module 604 receives parameters from the FPGA module 601 and generates microwave signals, which are output to the microwave switch 8. The data acquisition module 602 receives parameters from the photoelectric converter 5 and outputs them to the FPGA module 601. The timing pulse module 603 receives parameters from the FPGA module 601 and outputs them to the microwave switch 8 and the acousto-optic modulator 3.

[0070] refer to Figure 3As shown, the present invention proposes a current measurement method based on quantum technology, comprising the following steps: Step 1, wide-field band scanning; Step 2, selecting feature points based on resonance peaks; Step 3, sweeping the frequency of feature points after current change; Step 4, judging the offset properties; if the resonance peak is nearby, jump to Step 5, otherwise return to Step 1; Step 5, apply the offset estimation algorithm; Step 6, lock the new resonance peak; then return to Step 2.

[0071] refer to Figure 4 As shown, for a single resonance peak, a specific frequency point (e.g., when the atomic source is a diamond NV color center, a frequency point at 2870MHz is selected), the peak apex, and three pairs of points symmetrical about the peak are selected as characteristic points.

[0072] A characteristic embodiment of the current measurement process of this invention is as follows:

[0073] (1) Output control commands through the host computer 9, including setting the instrument output, setting experimental parameters (microwave sweep frequency setting, timing pulse setting), selecting the experimental type, and setting the data storage location;

[0074] (2) The pulse generation module 603 generates pulses to control the on / off state of the microwave switch 8 and the acousto-optic modulator 3. The laser generated by the laser source 2 is periodically transmitted to the diamond sample 4. The microwave signal generated by the microwave module 604 is amplified by the power amplifier 7 and periodically transmitted to the diamond sample 4.

[0075] (3) The magnetic field generated by the current flowing through the test wire 1 and the coupling effect of the laser and microwave cause the diamond sample 4 to undergo corresponding fluorescence changes. The generated fluorescence is converted into an electrical signal by the photoelectric converter 5 and collected by the data acquisition module 602.

[0076] (4) Application of FPGA module 601, such as Figure 3 This illustrates a current measurement method based on quantum technology.

[0077] (5) The host computer 9 receives the data processing results from the electrical integration module 6 and plots the current measurement result-time curve.

[0078] Contents not described in detail in this specification are prior art known to those skilled in the art. It is hereby indicated that the above description is intended to help those skilled in the art understand this invention, but does not limit the scope of protection of this invention. Any equivalent substitutions, modifications, improvements, and / or simplifications of the above descriptions that do not depart from the essential content of this invention fall within the scope of protection of this invention.

Claims

1. A current measurement method based on quantum technology, characterized in that, The method includes bringing an atomic source close to the conductor under test to couple the magnetic field signal generated by the current in the conductor. The atomic quantum state manipulation system of the atomic source is connected to a host computer through an electrical integration module. Based on optically detected magnetic resonance technology, during the measurement process, feature points are selected near the resonance peak of the optically detected magnetic resonance for frequency sweeping. The feature point positions are adaptively updated based on the feature point frequency sweeping results, so that the microwave signal frequency band adaptively matches the resonance peak and obtains the current measurement value. By using feature point frequency sweeping instead of global frequency sweeping, the measurement speed is improved.

2. The current measurement method based on quantum technology according to claim 1, characterized in that, The atomic source is a diamond NV color center. The atomic quantum state manipulation system includes an acousto-optic modulator connected to the diamond NV color center. The acousto-optic modulator is connected to a laser. The diamond NV color center is connected to a microwave module in an electrical integrated module via a microwave amplifier and a microwave switch. The diamond NV color center is connected to a data acquisition module in the electrical integrated module via a photoelectric converter. The acousto-optic modulator and the microwave switch are respectively connected to a timing pulse module in the electrical integrated module. The data acquisition module, the microwave module, and the timing pulse module are all connected to the host computer via an FPGA module. The magnetic field generated by the current in the tested wire and the coupling effect of the laser and microwave cause the diamond NV color center to undergo a corresponding fluorescence change. The generated fluorescence is converted into an electrical signal by the photoelectric converter and collected by the data acquisition module.

3. The current measurement method based on quantum technology according to claim 1, characterized in that, Includes the following steps: Step 1: Perform a microwave frequency sweep and fluorescence detection covering the entire measurement range, and plot the ODMR curve; Step 2: Based on the mathematical model, fit the ODMR curve and extract the NV color center quantum state signal; Step 3: Based on the fitted curve, select several observation points in the resonance peak region as feature points; Step 4: Perform a new round of microwave frequency sweep and fluorescence detection only on the feature points; Step 5: Based on the offset estimation algorithm, the offset direction and distance of the resonance peak are calculated using the two detection results of the feature points. The new resonance peak curve is obtained by fitting the offset information, the NV color center quantum state signal is extracted, and new feature points are selected. Step 6: Repeat steps 4 and 5 until a new resonance peak is locked, then return to step 3.

4. The current measurement method based on quantum technology according to claim 3, characterized in that, The mathematical model in step 2 is expressed as follows: ， In the formula, y is the measured current, n represents the number of resonance peaks, and j is the sequence number. Let represent the amplitude of the j-th resonance peak, e be the natural constant, and x be the microwave sweep frequency. The x-coordinate of the vertex of the j-th resonance peak is represented by the x-coordinate of the vertex of the j denoted by , represents the half-height and half-width of the j-th resonance peak, and m represents the offset of the j-th resonance peak on the vertical axis.

5. The current measurement method based on quantum technology according to claim 3, characterized in that, Step 3 includes the following expression: ， in It represents the x-coordinate of the i-th feature point. is the number of feature points selected for each resonance peak, l is the distance in the x-direction between adjacent feature points, and N is a natural number.

6. The current measurement method based on quantum technology according to claim 3, characterized in that, Step 5 includes the following expression: ， ， in It is the offset direction of the value in the i-th position of the sequence. It is the measured value of the i-th characteristic point after the current changes. It is the measured value of the i-th characteristic point before the current change. It is the resonance peak shift distance. yes x-coordinate yes x-coordinate It is the measured value at any characteristic point after the current changes. It represents any feature point.

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