Direct current measuring system based on diamond NV color center

Abstract

The invention discloses a direct current measurement system based on a diamond NV color center, and the system comprises a drive control module which is used for controlling a laser excitation module to emit laser, transmitting the laser to the NV color center of a diamond substrate, and enabling the NV color center to emit fluorescence; the microwave excitation module generates a frequency modulation microwave signal based on a to-be-detected electrified conductor magnetic field, and the frequency modulation microwave signal performs microwave modulation on the electron spin state of the NV color center; the magnetism gathering module is used for gathering magnetism around the electrified wire to be measured to form a stable and uniform magnetic field for NV color center measurement; the photoelectric detection module is used for collecting fluorescence emitted by the NV color center; the fluorescence analysis processing module is used for analyzing the intensity and the frequency of the fluorescence; determining the magnetic field of the electrified conductor according to the fluorescence intensity and frequency; and determining the current value of the to-be-measured electrified conductor based on the magnetic field. Under the condition that the module space is saved, the accuracy and the stability of module operation are ensured.

Description

Technical Field

[0001] The invention relates to the field of electric energy metering, and in particular to a direct current measurement system based on diamond NV color centers. Background Art

[0002] With the rapid development of quantum information technology, quantum sensing measurement systems based on diamond NV centers have attracted widespread attention due to their unique physical properties. Diamond NV centers (nitrogen-vacancy centers) are a new type of quantum sensor material with high sensitivity and stability in magnetic field measurement, providing a new opportunity for the development of current precision sensing measurement technology. For the precision current sensing measurement technology of diamond NV centers, relevant research has been carried out mainly around high-sensitivity measurement methods, measurement device development, and measurement performance simulation, and certain research results have been achieved. However, at present, most current sensing systems and equipment based on NV centers are in the stage of prototype system construction and equipment development. The current sensing measurement equipment based on NV centers has a relatively complex structure and a large volume, and it is difficult to combine with other electronic devices to form a complete current measurement product. Therefore, it is urgent to study the miniaturized current measurement module based on diamond NV centers and its integration and testing methods to provide technical support for the implementation of quantum sensing measurement equipment. Summary of the invention

[0003] In view of the above technical problems, the present invention provides a direct current measurement system based on diamond NV color center, comprising: a diamond substrate, a laser excitation module, a laser transmission module, a microwave excitation module, a microwave transmission module, a photoelectric detection module, a fluorescence analysis module and a drive control module;

[0004] The drive control module is used to control the laser excitation module to emit laser, and transmit the laser to the NV color center of the diamond substrate through the laser transmission module, so that the NV color center emits fluorescence; the drive control module controls the microwave excitation module to generate a frequency-modulated microwave signal based on the magnetic field of the energized conductor to be tested, and the frequency-modulated microwave signal performs microwave modulation on the electronic spin state of the diamond NV color center through the microwave transmission module;

[0005] After the frequency modulated microwave signal is received by the photoelectric control and measurement module, it is sent to the fluorescence analysis and processing module;

[0006] The magnetic field focusing module is used to gather the magnetic field around the energized conductor to be tested, forming a stable and uniform magnetic field in the air gap for NV color center measurement;

[0007] Photoelectric detection module, used to collect the fluorescence emitted by the NV color center;

[0008] The fluorescence analysis and processing module is used to analyze the fluorescence intensity and frequency of the fluorescence emitted by the NV color center; determine the magnetic field size of the current-carrying conductor according to the fluorescence intensity and frequency; and determine the current value of the current-carrying conductor to be tested based on the magnetic field size.

[0009] Furthermore, it also includes:

[0010] The diamond substrate, laser excitation module, laser transmission module, microwave excitation module, microwave transmission module, photoelectric detection module, fluorescence analysis module and drive control module are integrated into an integrated NV color center current measurement module by using an on-chip integrated micro-nano integration method.

[0011] Align the laser excitation module and the photoelectric control and measurement module with the center of the diamond NV color center, and use optical fiber or waveguide to connect the devices;

[0012] Automatically align the device for miniaturization and alignment;

[0013] Match the microwave excitation module with the resonance frequency of the NV color center, and use micro-wires, thin-film circuits and integrated circuits to make micro-nano-level electrical connections between devices;

[0014] The module is packaged using an airtight packaging structure.

[0015] Furthermore, the NV color center is integrated on a diamond substrate.

[0016] Furthermore, the laser excitation module is used to generate accurate timing control signals, adjust laser parameter data according to measurement requirements, and achieve accurate control of laser pulses.

[0017] Furthermore, the laser pulse includes: pulse width, repetition frequency and energy.

[0018] Furthermore, the laser transmission module is used to adjust the shape and direction of the laser beam to ensure that the laser can be focused on the NV color center.

[0019] Furthermore, the microwave excitation module is used to apply resonant microwave energy to the NV color center and manipulate the spin state of the NV color center.

[0020] Furthermore, the photoelectric detection module is also used to convert the fluorescence signal of the NV color center into an electrical signal.

[0021] Furthermore, the diamond substrate, laser excitation module, laser transmission module, microwave excitation module, microwave transmission module, photoelectric detection module, fluorescence analysis module and drive control module adopt an airtight packaging structure.

[0022] Furthermore, the fluorescence analysis and processing module performs analog-to-digital conversion and filtering on the fluorescence signal emitted by the NV color center, and then performs frequency analysis through fast Fourier transform.

[0023] The present invention provides a direct current measurement system based on diamond NV color center. When laying out the modules, the position and relative distance of each module are fully considered to minimize the interference between them and ensure the reasonable wiring of the optical path and circuit. The optical components are precisely aligned and integrated based on the self-calibration mechanism to ensure the effective transmission of laser and fluorescence signals. The heat dissipation structure and thermal isolation material are used, and the signal processing module and the photoelectric detection module are tightly integrated. The module is packaged based on the airtight packaging technology using the thermal interface, which ensures the accuracy, stability and reliability of the module operation while saving the module space. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a structural diagram of a direct current measurement system based on diamond NV color centers provided by an embodiment of the present invention;

[0025] Figure 2 The diamond substrate structure involved in the embodiment of the present invention;

[0026] Figure 3 This is the laser excitation module structure involved in the embodiment of the present invention;

[0027] Figure 4 The microwave excitation module structure involved in the embodiment of the present invention;

[0028] Figure 5 The photoelectric detection module structure involved in the embodiment of the present invention;

[0029] Figure 6 The present invention relates to a current measurement method based on diamond NV color centers. DETAILED DESCRIPTION

[0030] Many specific details are set forth in the following description to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways than those described herein, and those skilled in the art can make similar generalizations without violating the connotation of the present invention, so the present invention is not limited to the specific implementation disclosed below.

[0031] In order to solve the problem of miniaturization and practical application of direct current measurement modules based on diamond NV color centers, the present invention proposes a direct current measurement system based on diamond NV color centers, which mainly includes: a diamond substrate, a laser excitation module, a laser transmission module, a microwave excitation module, a microwave transmission module, a photoelectric detection module, a fluorescence analysis module and a drive control module; the above components are integrated into an integrated NV color center current measurement module by adopting an on-chip integrated micro-nano integration method; the optical path and the circuit are reasonably wired in consideration of heat flux density and space limitations, that is, the laser excitation module and the photoelectric detection module are aligned with the center position of the diamond NV color center, optical fiber and waveguide technology are used to connect optical devices, and micro-nano processing technology is used to perform miniaturization and automatic alignment of optical devices; the microwave excitation module is matched with the resonance frequency of the NV color center, and micro-conductors, thin film circuits and integrated circuits are used for micro-nano electrical connection between devices; the signal transmission interface adopts a high-speed, low-latency and high-bandwidth communication interface; the module is packaged by an airtight packaging structure; the overall logical structure of the current measurement module of the diamond NV color center is as follows Figure 1 shown.

[0032] The drive control module is used to control the laser excitation module to emit laser, and transmit the laser to the NV color center of the diamond substrate through the laser transmission module, so that the NV color center emits fluorescence; the drive control module controls the microwave excitation module to generate a frequency-modulated microwave signal based on the magnetic field of the energized conductor to be tested, and the frequency-modulated microwave signal performs microwave modulation on the electronic spin state of the diamond NV color center through the microwave transmission module;

[0033] After the frequency modulated microwave signal is received by the photoelectric control and measurement module, it is sent to the fluorescence analysis and processing module;

[0034] The magnetic field focusing module is used to gather the magnetic field around the energized conductor to be tested, forming a stable and uniform magnetic field in the air gap for NV color center measurement;

[0035] Photoelectric detection module, used to collect the fluorescence emitted by the NV color center;

[0036] The fluorescence analysis and processing module is used to analyze the fluorescence intensity and frequency of the fluorescence emitted by the NV color center; determine the magnetic field size of the current-carrying conductor according to the fluorescence intensity and frequency; and determine the current value of the current-carrying conductor to be tested based on the magnetic field size.

[0037] The diamond substrate mainly includes NV color center, optoelectronic control submodule, filter and signal transmission antenna. The diamond substrate is made by chemical vapor deposition method and is a convex polyhedral crystal composed of carbon atoms. Each carbon atom is connected to the surrounding carbon atoms by covalent bonds. The structure of the diamond substrate is as follows: Figure 2 shown.

[0038] The NV color center is integrated on the diamond substrate and is a defect in the diamond lattice, formed by a nitrogen atom replacing a carbon atom and forming a vacancy at its adjacent position.

[0039] The photoelectric control submodule is a planar comb-shaped structure, integrated with micrometer or nanometer-level electrodes, which is convenient for generating a highly localized uniform electric field. The electronic spin state of the NV color center is mainly controlled by the interaction with the external electric field.

[0040] The photoelectric control submodule, front and rear coatings, filters and signal transmission antenna configured on the diamond substrate provide a stable physical environment for the photoelectric detection of diamond NV color centers.

[0041] The laser excitation module mainly includes a pump source, a laser medium, a frequency doubling crystal, a resonance module, a temperature monitoring module, and an excitation control module. Figure 3 shown.

[0042] The pump source is a semiconductor pump module, which is a diode laser based on a wavelength of 808nm and is used to excite the laser medium.

[0043] The laser medium is yttrium vanadate (YVO4) doped with neodymium (Nd) or other doped materials, which can generate laser when excited by light of appropriate wavelength.

[0044] The laser medium is yttrium vanadate (YVO4) doped with neodymium (Nd) or other doped materials, which can generate laser when excited by light of appropriate wavelength.

[0045] The temperature monitoring module includes a plurality of highly sensitive semiconductor temperature sensors, which convert temperature changes into electrical signals for monitoring the heat generated by the laser during operation.

[0046] The laser excitation control module is mainly used to generate accurate timing control signals, adjust laser parameters according to measurement requirements, and achieve accurate control of laser pulses, including pulse width, repetition frequency and energy.

[0047] The laser transmission module integrates multiple optical components such as lenses, beam splitters, dichroic mirrors, plan achromatic objectives and beam collimators on a single chip using micro-nano processing technology to adjust the shape and direction of the laser beam and ensure that the laser can be effectively focused on the NV color center.

[0048] The microwave excitation module mainly includes a microwave source, a power amplification submodule, a frequency tuning and control submodule, and an impedance matching submodule. The microwave excitation module applies resonant microwave energy to the NV color center, manipulates the spin state of the NV color center, and realizes magnetic resonance measurement, such as Figure 4 shown.

[0049] The microwave source comprises a microwave signal generator for generating a microwave signal with a specific frequency and power.

[0050] The power amplification submodule mainly includes a power amplifier, which is used to enhance the power of the microwave signal and ensure that the microwave signal has sufficient energy to interact with the NV color center.

[0051] The frequency tuning and control submodule mainly includes an electronic coordinator, which is used to control the resonant frequency so that the external electromagnetic waves match the resonant frequency of the electromagnetic control transmission module, thereby generating the maximum electric field strength and improving the response sensitivity of the NV color center to microwave signals.

[0052] The control submodule is mainly used to generate control signals, adjust the output of the microwave source, and ensure the stability and repeatability of the microwave signal.

[0053] The microwave transmission module mainly includes a coaxial cable to transmit microwave signals to the diamond NV center. The signal transmission module is a parallel combination structure of multiple small capacitors, which transmits external electrical signals to the NV center through the capacitive coupling effect, and transmits the response signal of the NV center back to the reading system.

[0054] The photoelectric detection module mainly includes a fluorescence detection module, a fiber coupling submodule, a spectrum filtering module, a photoelectric conversion module, a preamplification module and a signal processing module, which are used to convert the fluorescence signal of the NV color center into an electrical signal, such as Figure 5 shown.

[0055] The surface of the fluorescence detection module is coated with a layer of high-reflectivity metal coating to increase the light collection efficiency of the detection module;

[0056] The fiber coupling module is mainly used to efficiently collect and transmit fluorescence, guide the fluorescence signal to the photoelectric conversion module, and can also focus the laser on the NV color center.

[0057] The spectral filtering module is mainly used to filter light of a specific wavelength, reduce background noise, and improve the signal-to-noise ratio.

[0058] The photoelectric conversion module mainly converts optical signals into electrical signals. It mainly includes photodiodes, photomultiplier tubes (PMTs) and avalanche photodiodes (APDs). These devices have high sensitivity and fast response time and can detect single photons.

[0059] The preamplifier module is mainly used to amplify the signal to ensure signal quality.

[0060] The signal processing module is mainly used to further process the amplified electrical signal, including filtering, amplification and conversion operations.

[0061] Magnetic focusing module: The magnetic focusing module is made of high magnetic permeability materials and is used to concentrate the magnetic field and enhance the sensitivity of the NV color center to electric field changes. The magnetic field around the energized wire is gathered to form a stable and uniform magnetic field in the air gap for NV color center measurement;

[0062] Drive control module: mainly uses FPGA technology to form an integrated drive control module, which is responsible for generating and controlling the magnetic field and detecting photoelectric signals. It includes sub-functional modules such as laser excitation drive, microwave source drive, signal amplification and data processing.

[0063] The fluorescence analysis and processing module is mainly used to perform analog-to-digital conversion, filtering and other processing on the collected weak fluorescence signals, and finally realize spectrum analysis through Fast Fourier Transform (FFT).

[0064] The NV color center current measurement module is integrated using on-chip integrated micro-nano integration technology, and optical path and circuit wiring are performed based on heat flux density and space limitation analysis, that is, the laser excitation module and the photoelectric detection module are aligned with the center position of the diamond NV color center, and the microwave excitation module is matched with the resonance frequency of the NV color center; a finger-shaped heat dissipation structure and thermal isolation materials are used to ensure the stability and reliability of the chip; optical fiber and waveguide technology are used to connect optical devices, and micro-nano processing technology is used to automatically align the miniaturization of optical devices and the collimation; micro-wires, thin film circuits and integrated circuits are used to make micro-nano electrical connections between devices; a high-speed, low-latency and high-bandwidth communication interface is used for the signal transmission interface; and the module as a whole adopts an airtight packaging structure.

[0065] The current measurement method based on diamond NV color center mainly uses the optical properties and spin quantum coherence of diamond NV color center to perform magnetic measurement and indirectly realize current measurement. The main measurement process is as follows: Figure 6 shown.

[0066] (1) First, the laser excitation module emits a laser with a wavelength of 532nm to the diamond NV color center, which stimulates the energy level transition of the diamond NV color center;

[0067] (2) When the NV color center is de-excited, it emits fluorescence;

[0068] (3) The microwave excitation module generates frequency modulated microwaves based on the magnetic field of the current-carrying conductor;

[0069] (4) Frequency-modulated microwaves modulate the electron spin state of the diamond NV color center;

[0070] (5) The modulated signal is received by the photodetector and sent to the fluorescence analysis processor for fluorescence intensity and frequency analysis, and the magnetic field of the current-carrying conductor is calculated based on the Zeeman effect;

[0071] (6) By monitoring the magnetic induction intensity around the current-carrying conductor, the magnitude of the current can be inferred.

[0072] The present invention designs a direct current measurement module based on diamond NV color center, and proposes a direct current measurement system based on diamond NV color center. When laying out the modules, the positions and relative distances of the modules are fully considered to minimize the interference between them and ensure the reasonable wiring of the optical path and circuit. The optical components are precisely aligned and integrated based on the self-calibration mechanism to ensure the effective transmission of laser and fluorescence signals. The heat dissipation structure and thermal isolation material are used, and the signal processing module and the photoelectric detection module are tightly integrated. The module is packaged based on the airtight packaging technology using a thermal interface, and the accuracy, stability and reliability of the module operation are guaranteed while saving the module space.

[0073] The current measurement method based on diamond NV color centers proposed in the present invention can accurately realize current measurement as small as mA and roughly kA level, and has the characteristics of good stability and high accuracy. It has broad application prospects in the field of electromagnetic measurement.

[0074] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0075] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0076] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0077] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0078] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents, and any modifications or equivalents that do not depart from the spirit and scope of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A direct current measurement system based on diamond NV color centers, characterized in that: include: Diamond substrate, laser excitation module, laser transmission module, microwave excitation module, microwave transmission module, photoelectric detection module, fluorescence analysis module and drive control module; The drive control module is used to control the laser excitation module to emit laser, and transmit the laser to the NV color center of the diamond substrate through the laser transmission module, so that the NV color center emits fluorescence; the drive control module controls the microwave excitation module to generate a frequency-modulated microwave signal based on the magnetic field of the energized conductor to be tested, and the frequency-modulated microwave signal performs microwave modulation on the electronic spin state of the diamond NV color center through the microwave transmission module; After the frequency modulated microwave signal is received by the photoelectric control and measurement module, it is sent to the fluorescence analysis and processing module; The magnetic field focusing module is used to gather the magnetic field around the energized conductor to be tested, forming a stable and uniform magnetic field in the air gap for NV color center measurement; Photoelectric detection module, used to collect the fluorescence emitted by the NV color center; The fluorescence analysis and processing module is used to analyze the fluorescence intensity and frequency of the fluorescence emitted by the NV color center; determine the magnetic field size of the current-carrying conductor according to the fluorescence intensity and frequency; and determine the current value of the current-carrying conductor to be tested based on the magnetic field size.

2. The system according to claim 1, characterized in that Also includes: The diamond substrate, laser excitation module, laser transmission module, microwave excitation module, microwave transmission module, photoelectric detection module, fluorescence analysis module and drive control module are integrated into an integrated NV color center current measurement module by using an on-chip integrated micro-nano integration method. Align the laser excitation module and the photoelectric control and measurement module with the center of the diamond NV color center, and use optical fiber or waveguide to connect the devices; Automatically align the device for miniaturization and alignment; Match the microwave excitation module with the resonance frequency of the NV color center, and use micro-wires, thin-film circuits and integrated circuits to make micro-nano-level electrical connections between devices; The module is packaged using an airtight packaging structure.

3. The system according to claim 1, characterized in that The NV color center is integrated on a diamond substrate.

4. The system according to claim 1, characterized in that The laser excitation module is used to generate accurate timing control signals, adjust laser parameter data according to measurement requirements, and achieve accurate control of laser pulses.

5. The system according to claim 4, characterized in that The laser pulse includes: pulse width, repetition frequency and energy.

6. The system according to claim 1, characterized in that The laser transmission module is used to adjust the shape and direction of the laser beam to ensure that the laser can be focused on the NV color center.

7. The system according to claim 1, characterized in that The microwave excitation module is used to apply resonant microwave energy to the NV color center and manipulate the spin state of the NV color center.

8. The system according to claim 1, characterized in that The photoelectric detection module is also used to convert the fluorescence signal of the NV color center into an electrical signal.

9. The system according to claim 1, characterized in that The diamond substrate, laser excitation module, laser transmission module, microwave excitation module, microwave transmission module, photoelectric detection module, fluorescence analysis module and drive control module adopt an airtight packaging structure.

10. The system according to claim 1, characterized in that The fluorescence analysis and processing module performs analog-to-digital conversion and filtering on the fluorescence signal emitted by the NV color center, and then performs frequency analysis through fast Fourier transform.

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