Diamond NV color center quantum sensing teaching machine based on industrial camera

Abstract

The embodiment of the invention discloses a diamond NV color center quantum sensing teaching machine based on an industrial camera. Comprising an integrated circuit module used for generating microwaves and radio frequency waves and providing a constant-current power supply; the integrated laser module is connected with the integrated circuit module and is configured to generate laser by using a constant-current power supply; the on / off of the laser is controlled by radio frequency waves; the integrated light path module is arranged to be connected with the integrated circuit module and the integrated laser module respectively, and is configured to receive the laser generated by the integrated laser module, excite the diamond NV color center under the action of the laser, and collect a fluorescence image formed by the diamond NV color center by using an industrial camera; the microwave generated by the integrated circuit module is received to control the diamond NV color center to spin; and the control module is used for controlling the integrated optical path module and the integrated circuit module.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of quantum sensing, and particularly relates to a diamond NV color center quantum sensing teaching machine based on an industrial camera. BACKGROUND

[0002] Quantum technologies such as quantum computing, quantum communication and quantum sensing are expected to break through the limitations of traditional technologies, significantly improve computing speed, ensure the absolute security of information communication, and improve the measurement accuracy by several orders of magnitude. Among existing quantum platforms such as trapped ions, neutral atoms and superconducting qubits, solid-state defect platforms have attracted widespread attention. Among them, the diamond nitrogen-vacancy (NV) center has long quantum coherence time at room temperature due to its spin degree of freedom, and can be conveniently initialized and read out through laser irradiation and fluorescence detection, and can be coherently manipulated under microwave radiation pulses. These unique properties make it the subject of in-depth research. The comprehensive use of these unique properties has given rise to the optical detection magnetic resonance technology, which has laid the foundation for the application of NV centers in various quantum technology fields.

[0003] The diamond NV center can be regarded as a quantum bit working at room temperature and normal pressure. Through experiments such as Rabi oscillation, Ramsey interference, Hahn echo and spin relaxation measurement, coherent manipulation of quantum bits can be demonstrated. Such experiments are fundamental and universal in many quantum platforms, so using diamond NV centers to carry out experiments has become an economical and convenient way for students or enthusiasts to master the basic principles of quantum technology. Currently, many start-up quantum technology companies have launched commercialized equipment, such as the diamond quantum computing teaching machine of Guoyi Quantum, the quantum magnetic force sensing teaching machine of Guosheng Quantum, the quNV quantum sensing teaching instrument of the German qutools company, and the quantum sensing teaching instrument of Advanced Quantum.

[0004] Existing NV color center quantum teaching equipment is usually based on a microscope structure, which uses an objective lens to focus laser light onto a diamond sample and improve the collection efficiency of weak NV color center fluorescence. However, these devices use high-sensitivity photodetectors or single-photon detectors for fluorescence acquisition, which on the one hand requires the use of expensive high-sensitivity photodetectors and photon counting or fluorescence acquisition units, increasing the complexity and cost of the equipment. On the other hand, the focusing of the laser spot, the diamond sample and the microwave radiator is difficult in quantum sensing experiments, and students cannot establish a direct impression of NV color center fluorescence and its microwave regulation in experiments, which increases the difficulty of the experiment and reduces the experimental effect. SUMMARY

[0005] Therefore, some embodiments disclose a diamond NV color center quantum sensing teaching machine based on an industrial camera, which comprises:

[0006] An integrated circuit module is configured to generate and control microwave and radio frequency waves, and provide a constant current power supply.

[0007] An integrated laser module is configured to generate laser light using the constant current power supply, and control the laser light on and off using the radio frequency waves.

[0008] An integrated optical path module is configured to receive the laser light generated by the integrated laser module, excite diamond NV color centers under the action of the laser light, and collect fluorescence imaging of the diamond NV color centers using an industrial camera; receive the microwave generated by the integrated circuit module and control the spin of the diamond NV color centers; and the industrial camera collects the fluorescence imaging under the control of the integrated circuit module.

[0009] A control module is configured to control the integrated optical path module and the integrated circuit module.

[0010] Further, some embodiments disclose a diamond NV color center quantum sensing teaching machine based on an industrial camera, wherein the integrated circuit module comprises:

[0011] A single-chip microcomputer;

[0012] A signal source is connected to the single-chip microcomputer; the signal source comprises a microwave signal source and a radio frequency signal source; the microwave signal source is configured to excite diamond NV color centers to generate optical detection magnetic resonance signals, and the radio frequency signal source is configured to drive an acousto-optic modulator of the integrated laser module.

[0013] Two attenuators are connected to the microwave signal source and the radio frequency signal source, respectively, and are configured to adjust the signal power generated by the microwave signal source and the radio frequency signal source, respectively.

[0014] Two switches are connected to the two attenuators, respectively, and are configured to control the on-off of the signals, respectively.

[0015] Two power amplifiers are connected to the two switches, respectively, and are configured to amplify the signals.

[0016] A digital delay pulse generator is connected to the two switches and the industrial camera, and is configured to receive signals from the control module to control the switches and the industrial camera.

[0017] A voltage-controlled constant current source is connected to the single-chip microcomputer, and is configured to generate a constant current source.

[0018] Some embodiments disclose a diamond NV color center quantum sensing teaching machine based on an industrial camera, wherein the integrated circuit module further comprises a band-pass filter arranged between the switch and the power amplifier.

[0019] Some embodiments disclose an industrial camera-based diamond NV color center quantum sensing teaching machine, an integrated laser module includes a semiconductor laser, a single-wavelength variable beam splitter, an acousto-optic modulator, a mirror, an aperture, and a fiber coupler arranged in sequence; the laser generated by the semiconductor laser enters the acousto-optic modulator after passing through the single-wavelength variable beam splitter, and after Bragg diffraction occurs in the acousto-optic modulator, the generated light spot is reflected by the mirror and then enters the aperture for filtering, and the selected first-order diffraction light spot is selected to enter the fiber coupler, and finally enters the optical fiber connected with the fiber coupler.

[0020] Some embodiments disclose an industrial camera-based diamond NV color center quantum sensing teaching machine, an integrated optical path module includes a sample stage, an objective lens, a mirror, a dichroic mirror, a plano-convex lens, a filter, and an industrial camera arranged in sequence, wherein the incident light direction of the dichroic mirror is provided with a fiber collimator; the incident laser passes through the fiber collimator and is reflected by the dichroic mirror to enter the mirror, and then is reflected by the mirror to enter the objective lens, and then is focused on the diamond NV color center on the sample stage to excite fluorescence, and the generated fluorescence passes through the objective lens, the mirror, the dichroic mirror, the filter, and the plano-convex lens in sequence and is collected by the industrial camera.

[0021] Some embodiments disclose an industrial camera-based diamond NV color center quantum sensing teaching machine, the sample stage includes:

[0022] A PCB board support;

[0023] A diamond sample arranged on the PCB board support;

[0024] A copper wire arranged closely to the surface of the diamond sample.

[0025] Some embodiments disclose an industrial camera-based diamond NV color center quantum sensing teaching machine, the sample stage is arranged on a three-dimensional displacement stage.

[0026] Some embodiments disclose an industrial camera-based diamond NV color center quantum sensing teaching machine, further comprising a magnet arranged in the sample stage to provide a magnetic field for the diamond NV color center on the sample stage.

[0027] The diamond NV color center quantum sensing teaching machine based on an industrial camera disclosed by the embodiments of the application adopts a modular design and is composed of an integrated optical path module, an integrated laser module, an integrated circuit module and a control module; the integrated optical path module composed of an industrial camera, a laser and an objective lens realizes imaging of laser focusing, diamond sample NV color center fluorescence and microwave copper wire radiation, reduces the difficulty of quantum sensing experiment operation, and enables NV color center fluorescence and microwave regulation to be more intuitively displayed; the region of interest (ROI) function is used to select the NV color center fluorescence region, the pixel points of the actual industrial camera are reduced, and the frame rate of the camera can reach more than 1 thousand; the software triggering function of the industrial camera and the software control of the microwave source in the self-developed integrated electronic module are used to realize the detection of continuous light detection magnetic resonance (ODMR) spectrum, and further combined with a small magnet, a thermocouple or a magnetic solenoid, the magnetic field and temperature detection based on the ODMR spectrum are realized, which lays a foundation for learning quantum sensing principle and sensitivity calculation. Further, a digital delay pulse generator is used to generate three pulse sequences, which are used to cooperatively control the laser, the microwave and the external trigger of the industrial camera, realize Rabi oscillation, Ramsey interference, Hahn echo and spin relaxation experiment, and lay a foundation for learning quantum bit coherent manipulation, quantum bit and environment interaction and quantum sequence extension quantum coherence time. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 The quantum sensing teaching machine disclosed by some embodiments is composed of a schematic diagram;

[0029] Figure 2 The integrated circuit module disclosed by some embodiments is composed of a schematic diagram;

[0030] Figure 3 The integrated laser module disclosed by some embodiments is composed of a schematic diagram;

[0031] Figure 4 The integrated optical path module disclosed by some embodiments is composed of a schematic diagram;

[0032] Figure 5 Optical detection of magnetic resonance (ODMR) experiment and quantum sensing result; wherein (a) NV color center microscopic imaging; (b) ODMR spectrum under different magnetic fields; (c) change of ODMR spectrum with magnetic field; (d) magnetic field quantum sensing; (e) change of ODMR spectrum with temperature; (f) temperature quantum sensing;

[0033] Figure 6 NV color center spin coherence manipulation experiment result; (a) Rabi oscillation experiment; (b) Ramsey experiment; (c) Hahn echo experiment; (d) spin relaxation experiment.

[0034] Reference signs

[0035] 1 integrated circuit module 2 integrated laser module

[0036] 3 integrated optical path module 4 control module

[0037] 11 single-chip microcomputer 12 radio frequency signal source

[0038] 13 microwave signal source 14 attenuator

[0039] 15 switch 16 power amplifier

[0040] 17 digital delay pulse generator 18 voltage-controlled constant current source

[0041] 21 semiconductor laser

[0042] 23 single-wavelength variable beam splitter 24 acousto-optic modulator

[0043] 25 mirror 26 diaphragm

[0044] 27 fiber coupler 31 industrial camera

[0045] 32 plano-convex lens 33 filter

[0046] 34 dichroic mirror 35 mirror

[0047] 36 objective lens 37 sample stage

[0048] 38 fiber collimator 39 magnet

[0049] 371 displacement stage 372 sample holder

[0050] 372 radiation body 374 microwave antenna DETAILED DESCRIPTION

[0051] The term "example" as used herein should not be construed as a limitation on the present embodiments unless specifically indicated otherwise. The performance index tests in the present embodiments are carried out by using the conventional test methods in the art, unless otherwise specified. It should be understood that the terms described in the present embodiments are merely used for describing the specific embodiments and are not intended to limit the disclosure of the present embodiments.

[0052] Unless otherwise specified, the technical and scientific terms used herein have the same meanings as commonly understood by those skilled in the art to which the present embodiments belong; the test methods and technical means not specifically indicated in the present embodiments refer to the test methods and technical means commonly used by those skilled in the art.

[0053] The terms "substantial" and "approximately" as used herein are used in relation to small fluctuations. For example, they can mean less than or equal to ± 5%, such as less than or equal to ± 2%, such as less than or equal to ± 1%, such as less than or equal to ± 0.5%, such as less than or equal to ± 0.2%, such as less than or equal to ± 0.1%, such as less than or equal to ± 0.05%. Numerical data may, in the examples herein, be presented in a range format. It is to be understood that such a range format is used only for convenience and brevity and thus should be taken as a recitation only of the explicit values that are included in the range. A description followed by a range of values herein, for example, "1-5%" is to be interpreted to include not only the explicitly recited values, but also the individual values within the range, and the sub-ranges within the range. For example, the values 1-5% should be interpreted to include not only the explicitly recited values of 1-5%, but also values such as 2, 3.5, and 4, and sub-ranges such as 1-3%, 2-4%, and 3-5%, etc. The same applies to ranges reciting only one numerical value. Furthermore, such an interpretation should apply regardless of the breadth of the range or the characteristics being described.

[0054] In this document, including in the claims, the conjunctions, such as "comprising", "including", "containing", "having", "involving", "holding", "characterized by", etc. are to be understood as open-ended, i.e. as meaning "including but not limited to". Only the conjunctions "consisting of" and "consisting exclusively of" are closed conjunctions.

[0055] For a better understanding of the present application, numerous specific details are given in the following detailed description. The person skilled in the art will understand that the application can be practiced without certain specific details, which are provided for a better understanding of the present application. In the examples, methods, means, instruments, devices, etc. that are well known to the person skilled in the art are not described in detail in order to highlight the gist of the present application.

[0056] The technical features disclosed in the embodiments of the present application can be combined in any manner without conflict, and the technical solutions obtained by the combination belong to the disclosure of the embodiments of the present application.

[0057] In some embodiments, as shown in Figure 1 The industrial camera-based diamond NV color center quantum sensing teaching machine comprises:

[0058] An integrated circuit module 1 is configured to generate microwaves, radio frequency waves, and provide a constant current power supply;

[0059] An integrated laser module 2 is connected with the integrated circuit module 1 and configured to generate laser light by using the constant current power supply; and the radio frequency waves are used to control the on-off of the laser light.

[0060] The integrated optical path module 3 is connected with the integrated circuit module 1 and the integrated laser module 2 respectively, configured to receive the laser generated by the integrated laser module 2, excite the diamond NV color center under the action of the laser, and collect the fluorescence imaging formed by the diamond NV color center by using an industrial camera; and receive the microwave generated by the integrated circuit module 1 and control the spin of the diamond NV color center.

[0061] The control module 4 is used for controlling the integrated optical path module 3 and the integrated circuit module 1. Generally, the control module includes a computer and a quantum sensing software module based on a Jupyter environment.

[0062] Generally, the integrated optical path module receives the laser from the integrated laser module to excite the NV color center, receives the command from the control module to realize the collection of the fluorescence imaging by using the industrial camera, and receives the microwave from the integrated circuit module to realize the manipulation of the spin of the NV color center; the integrated laser module receives the constant current power and the radio frequency signal from the integrated electronic module, the constant current power is used to drive the laser, and the radio frequency is used to drive the acousto-optic modulator to interrupt the laser, and the laser pulse is transmitted to the integrated optical path module through a multimode optical fiber; the integrated circuit module receives the command transmitted by the computer of the control module to generate the microwave, the radio frequency and the constant current power, and transmits them to the integrated optical path module and the integrated laser module respectively; the software module on the computer issues the command to the integrated circuit module to realize the control of the microwave and the radio frequency, receives the fluorescence imaging transmitted by the industrial camera to determine the position of the laser and the position of the NV color center layer, and realizes the quantum sensing experiments such as ODMR spectrum, Rabi oscillation, Ramsey interference, Hahn echo and spin relaxation through the analysis of the fluorescence imaging.

[0063] In some embodiments, as shown in FIG. 1, the integrated circuit module includes: Figure 2

[0064] The single-chip microcomputer 11;

[0065] The signal source is connected with the single-chip microcomputer 11; the signal source includes a microwave signal source 13 and a radio frequency signal source 12; the microwave signal source 13 is used to excite the diamond NV color center to generate an optical detection magnetic resonance signal, and the radio frequency signal source 12 is used to drive the acousto-optic modulator of the integrated laser module;

[0066] The attenuator 14 is provided with two, which are respectively connected with the microwave signal source 13 and the radio frequency signal source 12; and are respectively used to adjust the signal power generated by the microwave signal source 13 and the radio frequency signal source 12;

[0067] The switch 15 is provided with two, which are respectively connected with the two attenuators 14, and are respectively used to control the on-off of the microwave signal source 13 and the radio frequency signal source 12;

[0068] The power amplifier 16 is provided with two, which are respectively connected with the two switches 15, and are used to amplify the signal; ​

[0069] The digital delay pulse generator 17 is connected with the two switches 15 and the industrial camera with integrated optical module respectively, and is configured to receive the signal of the control module 4 to control the switches 15, so as to control the on-off of the microwave signal source 13 and the radio frequency signal source 12; and the on-off of the industrial camera;

[0070] The voltage-controlled constant current source 18 is connected with the single-chip microcomputer 11, and is configured to generate a constant current source.

[0071] The microwave signal source 13, the attenuator 14, the switch 15, and the power amplifier 16 are sequentially connected, and are further connected with a microwave antenna, and are configured to excite the diamond NV color center to generate a light detection magnetic resonance signal; the radio frequency signal source 12, the attenuator 14, the switch 15, and the power amplifier 16 are sequentially connected, and are further connected with an acousto-optic modulator of an integrated laser module, and are configured to drive the acousto-optic modulator.

[0072] Some embodiments of the diamond NV color center quantum sensing teaching machine based on an industrial camera further comprise a band-pass filter arranged between the switch and the power amplifier.

[0073] In some embodiments, the single-chip microcomputer is selected as STM32, the voltage-controlled constant current source is selected as KW-VCCS1000, the radio frequency source and the microwave source are selected as a radio frequency source chip ADF4351, the attenuator is selected as a radio frequency attenuator chip HMC624A, the switch is selected as a radio frequency switch Mini-Circuits: ZASWA-2-50DR+, the band-pass filter is selected as BPF88-108MHz, and the power amplifier is selected as a radio frequency power amplifier KDT700MPA-035 and KDT2038PA-045. Among them, the computer communicates with the single-chip microcomputer STM32 through USB, the single-chip microcomputer STM32 realizes radio frequency and microwave signals near 100MHz and 2.87GHz by configuring the registers of the radio frequency source and the microwave source chips ADF4351, and the single-chip microcomputer STM32 realizes the attenuation of the radio frequency and microwave signals by configuring the registers of the attenuator HMC624A; the digital delay pulse generator ASG sends three TTL signals, controls the on-off of the radio frequency and microwave signals through the radio frequency switch, triggers the industrial camera to collect the fluorescence imaging graph, and the radio frequency signal is amplified through the radio frequency power amplifier KDT700MPA-035 after passing through the band-pass filter, and then is output to the integrated laser module to drive the acousto-optic modulator AOM to realize the on-off of the laser; the microwave signal is directly output to the integrated optical module after being amplified through the radio frequency power amplifier KDT2038PA-045, and is used to control the spin of the NV color center; in addition, the single-chip microcomputer STM32 controls the voltage-controlled constant current source KW-VCCS1000 by controlling the digital-to-analog conversion to output an analog voltage, and outputs a constant current power supply to the integrated laser module to drive the semiconductor laser.

[0074] In some embodiments, such as Figure 3 As shown, the integrated laser module includes a semiconductor laser 21, a single-wavelength variable beam splitter 23, an acousto-optic modulator 24, a mirror 25, an aperture 26, and an optical fiber coupler 27 arranged sequentially. The laser generated by the semiconductor laser 21 enters the acousto-optic modulator 24 after passing through the single-wavelength variable beam splitter 23. After Bragg diffraction occurs in the acousto-optic modulator 24, the resulting light spot is reflected by the mirror 25 and enters the aperture 26. After being filtered by the aperture 26, the controllable first-order diffraction light spot enters the optical fiber coupler 27, and finally enters the multimode optical fiber connected to the optical fiber coupler.

[0075] Typically, the integrated laser module receives a constant current power supply and an RF signal from the integrated circuit module. The constant current power supply drives the semiconductor laser to generate a green laser with a wavelength of 532nm and a maximum power of 100mW. The laser beam power can be adjusted by a single-wavelength variable beam splitter. The acousto-optic modulator generates a grating with a periodic refractive index change under the drive of the RF signal (frequency of 100MHz, provided by the integrated circuit module). When the incident laser passes through this grating, Bragg diffraction occurs, generating zero-order and first-order beams. After being reflected by a mirror, the zero-order beam is blocked by an aperture, while the first-order beam can pass through. Finally, it is coupled into a multimode fiber through an optical fiber coupler.

[0076] In some embodiments, such as Figure 4 As shown, the integrated optical path module includes a sample stage 37, an objective lens 36, a reflector 25, a dichroic mirror 34, a plano-convex mirror 32, a filter 33, and an industrial camera 31 arranged sequentially. The sample stage 37 includes a displacement stage 371, with a sample holder 372 mounted above it. A radiator 372 for loading diamond samples is fitted onto the sample holder 372. A microwave receiving device is connected to the radiator 372 and the diamond sample loaded thereon. The microwave antenna 374 for the signal; wherein, the incident light direction of the dichroic mirror 34 is provided with an optical fiber collimator 38; the incident laser light passes through the optical fiber collimator 38 and is reflected by the dichroic mirror 34 into the reflecting mirror 35, and after being reflected by the reflecting mirror 35, it enters the objective lens 36, and is then focused onto the diamond NV color center on the sample stage 37 to excite fluorescence. The generated fluorescence passes sequentially through the objective lens 36, the reflecting mirror 35, the dichroic mirror 34, the filter 33, and the plano-convex mirror 32 before being collected by the industrial camera 31;

[0077] Magnet 39 is adapted to sample stage 37 to provide a magnetic field to the diamond NV color center on sample stage 37.

[0078] Generally, the integrated optical path module can be built with an optical cage structure based on an inverted microscope structure. The main optical elements used include optical fibers, optical fiber collimators, dichroic mirrors, mirrors, objectives, sample stages, 650 nm long-pass filters, 200 mm focal length plano-convex lenses, CMOS industrial cameras (MER2-160-249U3M-HS-6P, Daheng), and three-dimensional displacement stages. Two three-dimensional displacement stages are used to move the sample and the magnet, respectively. The entire optical path is installed on a breadboard, facilitating the handling and installation of the integrated optical path.

[0079] The 532 nm laser output by the integrated laser module is coupled into the integrated optical path module through a multimode optical fiber, enters the 45°-installed dichroic mirror after passing through the collimator, enters the objective lens after being reflected by the dichroic mirror and the mirror, and is finally focused on the diamond on the sample stage. Adjusting the three-dimensional displacement stage to move the sample stage realizes the relative movement of the diamond sample and the laser spot, adjusts the laser spot to the fluorescent micro-nano diamond particles, realizes the laser excitation of the NV color center, and returns the fluorescence of the NV color center through the original path, focuses on the photosensitive surface of the industrial camera after passing through the dichroic mirror and the filter.

[0080] In some embodiments, the sample stage includes a PCB board support, the diamond sample is arranged on the PCB board support, and a copper wire is arranged close to the surface of the diamond sample. Generally, the middle part of the copper wire is close to the surface of the diamond sample, the two ends of the copper wire are soldered to the PCB board support through soldering, and are further soldered to pins through soldering, and are connected to SMA wires through the pins to input microwaves. Further, a thermocouple can be arranged on the PCB board support corresponding to the diamond sample to heat the diamond for temperature sensing.

[0081] Some embodiments disclose a diamond NV color center quantum sensing teaching machine based on an industrial camera, wherein the sample stage is arranged on the three-dimensional displacement stage.

[0082] The technical details are further exemplarily described below in conjunction with embodiments.

[0083] Generally, the experimental process of the diamond color center quantum sensing teaching machine based on an industrial camera is as follows: first, 532 nm laser irradiation is applied to the diamond sample, the reflected microscopic imaging captured by the CMOS is obtained through the GalaxyViewer software, and the laser is focused on the micron diamond by adjusting the displacement stage. Then, the software in the Jupyter environment is used to realize continuous ODMR, magnetic field and temperature quantum sensing based on ODMR, Rabi oscillation, Ramsey, Hahn echo, and spin relaxation experiment.

[0084] Preparation of diamond sample for quantum sensing experiment

[0085] In order to be able to use a lower sensitivity industrial camera to directly collect the fluorescence of the NV center of the diamond sample, a fluorescent micron diamond with a diameter of 150 μm from Adámas company or a self-made bulk diamond sample can be used as the sample for quantum sensing experiment. The fluorescent micron diamond is prepared by high temperature and high pressure method, and then treated by electron irradiation and high temperature annealing. The concentration of NV center is about 3-4 ppm. The self-made bulk diamond sample is 111 diamond prepared by CVD or HTHP, which is also treated by electron irradiation and high temperature annealing. The concentration of NV center is about 0.4 ppm. Under the irradiation of 40 mW 532 nm laser (multimode fiber coupling power), the fluorescence signal of NV center in the sample is very strong, which can be observed by industrial camera in a short exposure time (within 500 μs), meeting the needs of all quantum experiments.

[0086] If micron diamond is used for quantum sensing experiment, the 150 μm micron diamond can be moved to the carrier glass slide using tweezers, and then the glass slide is placed on the PCB substrate of the sample stage. A 10 μm copper wire is pulled, which needs to be ensured to be close to the micron diamond, and the two sections are connected with two SMA interfaces respectively. Finally, the sample stage is connected with the three-dimensional displacement stage and placed above the objective lens. If bulk diamond is used for quantum sensing experiment, the CVD diamond sample can be bonded to the PCB substrate, and a 18 μm diameter copper wire is welded on the surface of the diamond. The microwave circuit connected to the PCB board is connected through tin, and the solution is immersed and treated with ethanol solution. The solution is solidified by evaporation to realize the firm adhesion of the wire to the surface of the diamond, so as to significantly enhance the coupling efficiency of microwave radiation and near-surface NV center. Finally, the sample stage is connected with the three-dimensional displacement stage and placed above the objective lens.

[0087] Experimental preparation

[0088] Preparation of diamond sample and installation of integrated optical path module;

[0089] Correct connection of three integrated modules and connection with computer;

[0090] Use Jupyter program to open laser, connect CMOS camera to obtain fluorescence microscopy imaging through GalaxyViewer software, adjust the stage to make the sample imaging clear;

[0091] Move the laser spot to the place where the fluorescent micro-nanoparticles are or the place where the bulk sample is close to the copper wire. Use Jupyter program to set the microwave frequency to 2.87 GHz and higher power. Turn off the microwave to observe whether the fluorescence changes to determine whether the equipment is running correctly, such as Figure 5 (a) shown in;

[0092] Quantum sensing experiment

[0093] Using the designed Jupyter program for continuous ODMR experiment, configure the center position and width of microwave sweep, microwave output power, camera exposure time, experimental repetition number, then run the program to obtain ODMR spectrum, and use Lorentz linear fitting to obtain the information of center frequency, contrast and line width;

[0094] Introduce external magnetic field by magnet at given pressure, split ODMR spectrum by Zeeman effect, adjust magnetic field to make external magnetic field and NV axis have different relationship, obtain 2, 4, 6 and 8 valley ODMR spectrum, as shown in (b) of Figure 5 ;

[0095] Use 111 face cut diamond sample, ODMR spectrum shows 4 valleys and 2.87GHz symmetry when magnet is above the sample, when magnet is gradually close to diamond sample, valley deviates from 2.87GHz and central valley gradually disappears, the size of vertical magnetic field can be deduced from the frequency of the outermost two valleys, as shown in (c) of Figure 5 ;

[0096] Using the designed Jupyter program, magnetic field can be tracked in quasi real time according to the above principle, and quantum sensing of magnetic field can be realized, as shown in (d) of Figure 5 ;

[0097] Tighten the thermoelectric cooling fin to the diamond sample and heat or cool, the whole ODMR spectrum will move, the frequency between two valleys is zero field splitting, which changes linearly with temperature near room temperature Figure 5 (e), using this feature, quasi real-time detection of temperature can be realized, as shown in (f) of Figure 5 .

[0098] For NV color center spin coherent manipulation experiment, still use 111 face cut diamond sample, make microwave frequency resonate with one of the two outermost valleys, select corresponding spin transition to form a two-level quantum bit for subsequent experiment;

[0099] Using the designed Jupyter program for Rabi oscillation experiment, apply laser pulse to polarize NV color center spin, then apply microwave pulse with variable length, then apply laser pulse and observe the change of fluorescence contrast, finally obtain a curve of fluorescence contrast oscillating and decaying with microwave pulse length, get π / 2 and π pulse time by fitting, as shown in (a) of Figure 6 ;

[0100] Ramsey experiments were performed using a pre-designed Jupyter program. A laser pulse was applied to polarize the spin of the NV center, followed by a (π) / (2) microwave pulse, allowing the NV center to evolve freely for a period of time. Another (π) / (2) microwave pulse was then applied, followed by a laser pulse, and the change in fluorescence contrast was observed. Finally, an oscillating decay curve of fluorescence contrast over the free evolution time was obtained. The dephase T2* time was obtained by fitting the curve, as shown in the figure. Figure 6 As shown in (b);

[0101] The Hahn echo experiment was conducted using a pre-designed Jupyter program. The sequence used was similar to that of the Ramsey experiment, but the free evolution was divided into two parts, and a π microwave pulse was inserted in the middle. The fluorescence contrast showed an exponential decay trend with the total free evolution time. The dephase T2 time was obtained by fitting.

[0102] like Figure 6 As shown in (c);

[0103] Spin relaxation time experiments were conducted using a pre-designed Jupyter program. The sequence used was the same as in the Rabi oscillation experiment, but the microwave pulses were replaced with free evolution. The resulting exponential decay curve of fluorescence contrast with free evolution time was fitted to obtain the spin relaxation time T1, as shown below. Figure 6 As shown in (d).

[0104] The technical solutions and technical details disclosed in the embodiments of this invention are merely illustrative of the inventive concept of this invention and do not constitute a limitation on the technical solutions of the embodiments of this invention. Any conventional changes, substitutions, or combinations made to the technical details disclosed in the embodiments of this invention have the same inventive concept as this invention and are within the protection scope of the claims of this invention.

Claims

1. A teaching machine for diamond NV color center quantum sensing based on an industrial camera, characterized in that, include: Integrated circuit modules are used to generate and control microwave and radio frequency waves and provide constant current power. An integrated laser module is connected to the integrated circuit module and configured to generate laser using a constant current power supply; the laser is controlled to be turned on and off using radio frequency waves. An integrated optical path module is configured to be connected to the integrated circuit module and the integrated laser module respectively, and to receive the laser generated by the integrated laser module, excite the diamond NV color center under the action of the laser, and use an industrial camera to collect fluorescence images formed by the diamond NV color center; receive the microwave generated by the integrated circuit module to control the spin of the diamond NV color center; and the industrial camera collects fluorescence images under the control of the integrated circuit module. The control module is used to control the integrated optical path module and the integrated circuit module.

2. The diamond NV color center quantum sensing teaching machine based on an industrial camera according to claim 1, characterized in that, The integrated circuit module includes: Microcontroller; A signal source is configured to be connected to the microcontroller; the signal source includes a microwave signal source and a radio frequency signal source; the microwave signal source is used to excite the diamond NV color center to generate a photodetector magnetic resonance signal, and the radio frequency signal source is used to drive the acousto-optic modulator of the integrated laser module; Attenuators; two attenuators are provided, respectively connected to the microwave signal source and the radio frequency signal source; used to adjust the signal power generated by the microwave signal source and the radio frequency signal source respectively; Two switches are provided, each connected to one of the two attenuators, for controlling the on / off state of the signal respectively. There are two power amplifiers, each connected to one of the two switches, used to amplify the signal; A digital delay pulse generator is configured to receive signals from the control module to control the switches and the industrial camera, respectively. A voltage-controlled constant current source is connected to the microcontroller to generate a constant current source.

3. The diamond NV color center quantum sensing teaching machine based on an industrial camera according to claim 2, characterized in that, The integrated circuit module also includes a bandpass filter disposed between the switch and the power amplifier.

4. The diamond NV color center quantum sensing teaching machine based on an industrial camera according to claim 1, characterized in that, The integrated laser module includes a semiconductor laser, a single-wavelength variable beam splitter, an acousto-optic modulator, a mirror, an aperture, and an optical fiber coupler arranged sequentially. The laser light generated by the semiconductor laser enters the acousto-optic modulator after passing through the single-wavelength variable beam splitter. After Bragg diffraction occurs in the acousto-optic modulator, the resulting light spot is reflected by the mirror and then filtered by the aperture. The first-order diffraction light spot that can be controlled is then selected to enter the optical fiber coupler, and finally enters the optical fiber connected to the optical fiber coupler.

5. The diamond NV color center quantum sensing teaching machine based on an industrial camera according to claim 1, characterized in that, The integrated optical path module includes a sample stage, an objective lens, a reflector, a dichroic mirror, a plano-convex mirror, a filter, and an industrial camera arranged sequentially. The incident light direction of the dichroic mirror is provided with an optical fiber collimator. The incident laser light passes through the optical fiber collimator, is reflected by the dichroic mirror, enters the reflector, is reflected by the reflector, enters the objective lens, and is then focused onto the diamond NV color center on the sample stage to excite fluorescence. The generated fluorescence passes sequentially through the objective lens, reflector, dichroic mirror, filter, and plano-convex mirror before being collected by the industrial camera.

6. The diamond NV color center quantum sensing teaching machine based on an industrial camera according to claim 5, characterized in that, The sample stage includes: PCB board support; A diamond sample is placed on the PCB board support. Copper wires are placed in close contact with the surface of the diamond sample.

7. The diamond NV color center quantum sensing teaching machine based on an industrial camera according to claim 5, characterized in that, The sample stage is set on a three-dimensional displacement stage.

8. The diamond NV color center quantum sensing teaching machine based on an industrial camera according to claim 5, characterized in that, It also includes a magnet, adapted to the sample stage, for providing a magnetic field to the diamond NV color centers on the sample stage.

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