Quantum diamond atomic force microscope electronics control readout system and method

Abstract

This disclosure provides an electronic control readout system and method for quantum diamond atomic force microscopy. The system includes: a system control readout module, a magnetic measurement algorithm module, and a magnetic measurement control and readout module. The magnetic measurement control and readout module is used to respond to the control signal of the system control readout module by emitting a laser pulse sequence and a microwave pulse sequence of a preset frequency to the quantum diamond probe located at the i-th pixel position of the sample to be tested, and then acquiring the analog fluorescence signal of the quantum diamond probe at the i-th pixel position and outputting the digital fluorescence signal of the i-th pixel. The magnetic measurement algorithm module is used to respond to the control signal of the system control readout module by obtaining the resonance frequency at the i-th pixel position and the preset frequency at the i+1-th pixel position according to the fluorescence photon number of the i-th pixel corresponding to the digital fluorescence signal of the i-th pixel, the resonance frequency at the (i-1)-th pixel position, and a microwave frequency lookup table.

Description

Technical Field

[0001] This disclosure relates to the field of atomic force microscopy, and more specifically, to an electronic control readout system and method for a quantum diamond atomic force microscope. Background Technology

[0002] The Quantum Diamond Atomic Force Microscope (QDAFM) is a microscopic measurement instrument used for scanning magnetic imaging. It combines the quantum diamond nitrogen-vacancy center (NV) magnetic field measurement principle with the scanning principle of atomic force microscopy, enabling magnetic imaging of the sample under test. It features high resolution, high sensitivity, and non-destructive measurement capabilities.

[0003] In the process of realizing the present invention, the inventors discovered that the related technologies have at least the following problems: In the related technologies, the method of using discrete devices and software on a host computer to control and read data from the QDAFM experimental system has problems such as low device integration, long communication time between devices, low synchronization between devices, and poor flexibility of experimental methods, which greatly increases the time cost of the experiment and the difficulty of equipment maintenance. Summary of the Invention

[0004] In view of this, the present disclosure provides an electronic control readout system and method for quantum diamond atomic force microscopy.

[0005] One aspect of this disclosure provides an electronically controlled readout system for a quantum diamond atomic force microscope, comprising:

[0006] The system includes a control and readout module, a magnetization algorithm module, and a magnetization control and readout module.

[0007] The aforementioned magnetic measurement control and readout module is used to respond to the control signal of the aforementioned system control and readout module, to emit a laser pulse sequence and a microwave pulse sequence of a preset frequency to the aforementioned quantum diamond probe located at the i-th pixel position of the sample to be tested, and then to collect the analog fluorescence signal of the aforementioned quantum diamond probe at the i-th pixel position of the sample to be tested, and output the digital fluorescence signal of the i-th pixel, where i is an integer greater than or equal to 2.

[0008] The aforementioned magnetic measurement algorithm module is used to respond to the control signal of the aforementioned system control readout module. Based on the number of fluorescent photons of the i-th pixel corresponding to the digital fluorescence signal of the i-th pixel, the resonance frequency at the (i-1)-th pixel position of the sample under test, and a microwave frequency lookup table, it obtains the resonance frequency at the i-th pixel position of the sample under test and the preset frequency at the (i+1)-th pixel position of the sample under test. The index of the microwave frequency lookup table is the value of multiple fluorescent photons at the first pixel position of the sample under test, and the value of the microwave frequency lookup table is a plurality of preset frequencies that correspond one-to-one with the values ​​of the multiple fluorescent photons. The resonance frequency is the frequency value at the lowest point of the Lorentz curve fitted to the number of fluorescent photons and the preset frequency corresponding to each pixel position of the sample under test.

[0009] According to embodiments of this disclosure, the above-mentioned magnetic measurement algorithm module includes:

[0010] The lookup table storage unit is used to store the values ​​of multiple fluorescent photon counts at the first test pixel position of the sample to be tested, and multiple preset frequencies that correspond one-to-one with the values ​​of the multiple fluorescent photon counts.

[0011] The preset frequency calculation unit is used to obtain the resonance frequency at the position of the i-th pixel and the preset frequency at the position of the i+1-th pixel of the sample based on the number of fluorescent photons of the i-th pixel corresponding to the digital fluorescence signal of the i-th pixel, the resonance frequency at the position of the i-1-th pixel of the sample to be tested, and the microwave frequency lookup table.

[0012] The parameter register is used to store the resonant frequency at the i-th pixel position of the sample to be tested and the preset frequency at the (i+1)-th pixel position of the sample to be tested.

[0013] According to embodiments of this disclosure, the above-mentioned magnetic measurement control and readout module includes:

[0014] The microwave generating unit is used to control the microwave generator to emit microwaves of a stable preset frequency according to the preset frequency at the position of the i-th pixel to be tested of the sample to be tested.

[0015] A sequence generator is used to convert laser light into the aforementioned laser pulse sequence and to convert microwave light of the aforementioned preset frequency into the aforementioned microwave pulse sequence of the aforementioned preset frequency.

[0016] An analog-to-digital converter circuit is used to acquire the analog fluorescence signal of the quantum diamond probe at the i-th pixel position of the sample to be tested, and to convert the analog fluorescence signal into the digital fluorescence signal.

[0017] According to embodiments of this disclosure, the system further includes a scanning control module;

[0018] The scanning control module is used to respond to the control signal of the system control readout module to control the quantum diamond probe of the quantum diamond atomic force microscope to move to the i-th pixel position of the sample to be tested.

[0019] According to embodiments of this disclosure, the scanning control module includes:

[0020] The displacement stage stabilization detection circuit is used to process the probe analog signal, output the probe digital signal to the system control readout module, and output the probe excitation analog signal to the quantum diamond probe of the quantum diamond atomic force microscope. The probe analog signal is an analog voltage signal corresponding to the interaction force between the quantum diamond probe of the quantum diamond atomic force microscope and the i-th pixel of the sample to be tested.

[0021] The analog input / output unit is used to output a digital signal of the displacement stage to the system control readout module based on the displacement stage analog signal related to the position of the displacement stage where the quantum diamond probe is located, and to output a displacement stage movement analog signal to the displacement stage to control the movement of the displacement stage, wherein the displacement stage movement analog signal includes a vertical movement analog signal and a horizontal movement analog signal of the displacement stage.

[0022] According to embodiments of this disclosure, the system control readout module includes:

[0023] The scanning digital signal processing unit is used to process the displacement stage digital signal related to the position of the displacement stage where the quantum diamond probe is located, and generate the displacement stage movement digital signal that controls the displacement stage where the quantum diamond probe is located to move. The displacement stage movement digital signal includes a vertical movement digital signal and a horizontal movement digital signal of the displacement stage.

[0024] The magnetic digital signal processing unit is used to output a microwave pulse sequence of a preset frequency corresponding to the i-th pixel position of the sample to be tested, and to process the digital fluorescence signal at the i-th pixel position of the sample to be tested, and output the fluorescence photon count.

[0025] The central logic processing unit is used to control the signal transmission between the aforementioned scanning digital signal processing unit, the aforementioned magnetometry digital signal processing unit, and the aforementioned magnetometry algorithm module.

[0026] According to embodiments of this disclosure, the above-mentioned scanning digital signal processing unit includes:

[0027] A digital lock-in amplifier is used to measure the probe digital signal as described above, output a lock-in amplified probe digital signal, and output a probe excitation digital signal to excite the vibration of the quantum diamond probe. The probe digital signal is a digital voltage signal corresponding to the force between the quantum diamond probe of the quantum diamond atomic force microscope and the i-th pixel position of the sample to be tested.

[0028] The feedback calculation subunit is used to perform feedback calculation on the above-mentioned lock-in amplified probe digital signal to generate a vertical movement digital signal of the displacement stage that controls the displacement stage where the quantum diamond probe is located to move in the vertical direction.

[0029] The digital scanning waveform generation subunit is used to output the vertical movement digital signal of the displacement stage and, according to the preset movement path, to output the horizontal movement digital signal of the displacement stage that controls the quantum diamond probe to move in the horizontal direction. The preset movement path represents the path for scanning each pixel position of the sample to be tested.

[0030] According to embodiments of this disclosure, the above-mentioned magnetic measurement digital signal processing unit includes:

[0031] The counting / acquisition subunit is used to count the above digital fluorescence signals to obtain the number of fluorescence photons;

[0032] The microwave frequency switching subunit is used to generate a microwave frequency digital signal that controls the microwave to switch to the preset frequency according to the preset frequency.

[0033] The digital sequence signal generation subunit is used to generate a sequence digital signal that controls the timing of the generation of the aforementioned microwave pulse sequence and the aforementioned laser pulse sequence.

[0034] According to embodiments of this disclosure, the system control readout module and the magnetic measurement algorithm module described above can be integrated into an FPGA.

[0035] Another aspect of this disclosure provides an electronically controlled readout method for quantum diamond atomic force microscopy, comprising:

[0036] In response to the control signal of the system control readout module, a laser pulse sequence and a microwave pulse sequence of a preset frequency are emitted to the quantum diamond probe located at the i-th pixel position of the sample to be tested. Then, the analog fluorescence signal of the quantum diamond probe at the i-th pixel position of the sample to be tested is acquired, and the digital fluorescence signal of the i-th pixel is output, where i is an integer greater than or equal to 2.

[0037] In response to the control signal of the system control readout module, the resonance frequency at the i-th test pixel position and the preset frequency at the i+1-th test pixel position of the sample are obtained according to the fluorescence photon count of the i-th pixel corresponding to the digital fluorescence signal of the i-th pixel, the resonance frequency at the (i-1)-th test pixel position of the sample, and the microwave frequency lookup table. The index of the microwave frequency lookup table is the value of multiple fluorescence photon counts at the first test pixel position of the sample, the value of the microwave frequency lookup table is the multiple preset frequencies that correspond one-to-one with the values ​​of the multiple fluorescence photon counts, and the resonance frequency is the frequency value at the lowest point of the Lorentz curve fitted to the fluorescence photon count and the preset frequency corresponding to each test pixel position of the sample.

[0038] According to embodiments of this disclosure, an electronic control readout system for a quantum diamond atomic force microscope is employed, comprising: a system control readout module, a magnetic measurement algorithm module, and a magnetic measurement control and readout module. The magnetic measurement control and readout module, in response to a control signal from the system control readout module, emits a laser pulse sequence and a microwave pulse sequence of a preset frequency to the quantum diamond probe located at the i-th pixel position of the sample under test. Then, it acquires the analog fluorescence signal of the quantum diamond probe at the i-th pixel position of the sample under test and outputs the digital fluorescence signal of the i-th pixel. The magnetic measurement algorithm module, in response to a control signal from the system control readout module, obtains the resonance frequency at the i-th pixel position and the preset frequency at the i+1-th pixel position of the sample under test based on the number of fluorescent photons of the i-th pixel corresponding to the digital fluorescence signal of the i-th pixel, the resonance frequency at the (i-1)-th pixel position of the sample under test, and a microwave frequency lookup table. This technique enables synchronous control and signal readout of laser, microwave, and other equipment using a single system, exhibiting high equipment integration and good experimental method flexibility. Simultaneously, the signals and data corresponding to each pixel position of the sample under test are processed in real time. The data transmission time is short and the synchronization is high, which ensures the measurement accuracy and efficiency of the system and reduces the time cost of the experiment and the difficulty of equipment maintenance. Attached Figure Description

[0039] The above and other objects, features and advantages of this disclosure will become clearer from the following description of embodiments with reference to the accompanying drawings, in which:

[0040] Figure 1 A schematic diagram of an electronic control readout system for a quantum diamond atomic force microscope according to an embodiment of the present disclosure is shown.

[0041] Figure 2 This schematic diagram illustrates the determination of the resonant frequency at the position of the pixel to be tested in a sample according to an embodiment of the present disclosure.

[0042] Figure 3 This illustration schematically shows a diagram of determining the preset frequency and fluorescence photon number of the pixel to be tested in a sample according to an embodiment of the present disclosure;

[0043] Figure 4 A schematic diagram of a magnetization algorithm module according to an embodiment of the present disclosure is shown.

[0044] Figure 5 A schematic diagram of a magnetometry control and readout module according to an embodiment of the present disclosure is shown.

[0045] Figure 6 A schematic diagram of a scanning control module according to an embodiment of the present disclosure is shown; and

[0046] Figure 7 A schematic diagram of a system control readout module according to an embodiment of the present disclosure is shown. Detailed Implementation

[0047] The embodiments of the present disclosure will now be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the disclosure. In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the embodiments of the present disclosure for ease of explanation. However, it will be apparent that one or more embodiments may be practiced without these specific details. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concepts of the present disclosure.

[0048] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0049] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

[0050] When using expressions such as "at least one of A, B, and C," the expression should generally be interpreted in accordance with the meaning commonly understood by a person skilled in the art (e.g., "a system having at least one of A, B, and C" should include, but is not limited to, systems having A alone, having B alone, having C alone, having A and B, having A and C, having B and C, and / or having A, B, and C, etc.). Similarly, when using expressions such as "at least one of A, B, or C," the expression should generally be interpreted in accordance with the meaning commonly understood by a person skilled in the art (e.g., "a system having at least one of A, B, or C" should include, but is not limited to, systems having A alone, having B alone, having C alone, having A and B, having A and C, having B and C, and / or having A, B, and C, etc.).

[0051] In related technologies, the method of controlling and reading data from a QDAFM experimental system using a combination of discrete devices and software on a host computer suffers from problems such as low device integration, long communication time between devices, low synchronization between devices, and poor flexibility of experimental methods, which greatly increases the time cost of experiments and the difficulty of equipment maintenance. Therefore, embodiments of this disclosure provide an electronic control and readout system and method for a quantum diamond atomic force microscope.

[0052] This disclosure provides an electronic control readout system for a quantum diamond atomic force microscope. The system includes: a system control readout module, a magnetic measurement algorithm module, and a magnetic measurement control and readout module. The magnetic measurement control and readout module, in response to a control signal from the system control readout module, emits a laser pulse sequence and a microwave pulse sequence of a preset frequency to a quantum diamond probe located at the i-th pixel position of the sample under test. It then acquires the analog fluorescence signal of the quantum diamond probe at the i-th pixel position of the sample under test and outputs the digital fluorescence signal of the i-th pixel, where i is an integer greater than or equal to 2. The magnetic measurement algorithm module is used in response to a control signal from the system control readout module. Based on the number of fluorescent photons of the i-th pixel corresponding to the digital fluorescence signal of the i-th pixel, the resonance frequency at the (i-1)-th pixel position of the sample under test, and the microwave frequency lookup table, the resonance frequency at the i-th pixel position of the sample under test and the preset frequency at the (i+1)-th pixel position of the sample under test are obtained. The index of the microwave frequency lookup table is the value of multiple fluorescent photons at the first pixel position of the sample under test, the value of the microwave frequency lookup table is multiple preset frequencies that correspond one-to-one with the values ​​of multiple fluorescent photons, and the resonance frequency is the frequency value at the lowest point of the Lorentz curve fitted by the number of fluorescent photons and the preset frequency corresponding to each pixel position of the sample under test.

[0053] According to embodiments of this disclosure, a quantum diamond atomic force microscope electronic control readout system is employed, comprising: a system control readout module, a magnetic measurement algorithm module, and a magnetic measurement control and readout module. The magnetic measurement control and readout module, in response to the control signal from the system control readout module, emits a laser pulse sequence and a microwave pulse sequence of a preset frequency to the quantum diamond probe located at the i-th pixel position of the sample under test. Then, it acquires the analog fluorescence signal of the quantum diamond probe at the i-th pixel position of the sample under test and outputs the digital fluorescence signal of the i-th pixel. The magnetic measurement algorithm module, in response to the control signal from the system control readout module, obtains the resonance frequency at the i-th pixel position and the preset frequency at the i+1-th pixel position of the sample under test based on the fluorescence photon number of the i-th pixel corresponding to the digital fluorescence signal of the i-th pixel, the resonance frequency at the (i-1)-th pixel position of the sample under test, and a microwave frequency lookup table. This technique enables synchronous control and signal readout of laser, microwave, and other equipment using the same system, exhibiting high equipment integration and good experimental method flexibility. Simultaneously, the signals and data corresponding to each pixel position of the sample under test are processed in real time. The data transmission time is short and the synchronization is high, which ensures the measurement accuracy and efficiency of the system and reduces the time cost of the experiment and the difficulty of equipment maintenance.

[0054] Figure 1 A schematic diagram of an electronic control readout system for a quantum diamond atomic force microscope according to an embodiment of the present disclosure is shown.

[0055] like Figure 1 As shown, the electronic control readout system of the quantum diamond atomic force microscope includes: system control readout module 1, magnetic measurement algorithm module 2, magnetic measurement control and readout module 3, and scanning control module 4.

[0056] The magnetic measurement control and readout module 3 is used to respond to the control signal of the system control and readout module 1, to emit a laser pulse sequence and a microwave pulse sequence of a preset frequency to the quantum diamond probe located at the i-th pixel position of the sample to be tested, and then to collect the analog fluorescence signal of the quantum diamond probe at the i-th pixel position of the sample to be tested, and output the digital fluorescence signal of the i-th pixel, where i is an integer greater than or equal to 2.

[0057] The magnetic measurement algorithm module 2 is used to respond to the control signal of the system control readout module 1. Based on the number of fluorescent photons of the i-th pixel corresponding to the digital fluorescence signal of the i-th pixel, the resonance frequency at the (i-1)-th pixel position of the sample under test, and the microwave frequency lookup table, it obtains the resonance frequency at the i-th pixel position of the sample under test and the preset frequency at the (i+1)-th pixel position of the sample under test. The index of the microwave frequency lookup table is the value of multiple fluorescent photons at the first pixel position of the sample under test, and the value of the microwave frequency lookup table is multiple preset frequencies that correspond one-to-one with the values ​​of multiple fluorescent photons. The resonance frequency is the frequency value at the lowest point of the Lorentz curve fitted by the number of fluorescent photons and the preset frequency corresponding to each pixel position of the sample under test.

[0058] like Figure 1 As shown, the system control readout module is connected to the host computer, the magnetic measurement algorithm module, the magnetic measurement control and readout module, and the scanning control module. It is used to communicate with the host computer before scanning and measuring the magnetic field, obtain the initial system parameters from the host computer, and configure the system parameters of the magnetic measurement algorithm module, the magnetic measurement control and readout module, and the scanning control module according to the initial system parameters.

[0059] According to embodiments of this disclosure, the system control readout module is also used to read back the operating status and system parameter configuration of the magnetic measurement algorithm module, the magnetic measurement control and readout module and the scanning control module during the scanning magnetic measurement process, and to transmit the resonant frequency at each pixel position of the sample to be measured calculated by the magnetic measurement algorithm module to the host computer.

[0060] According to embodiments of this disclosure, the initial system parameters include a microwave frequency lookup table and the resonant frequency f of the first pixel position of the sample under test. c And the path for scanning each pixel position of the sample under test.

[0061] According to an embodiment of this disclosure, the microwave frequency lookup table is generated by software in a host computer, and the resonant frequency of the first pixel position of the sample under test is obtained by software in the host computer.

[0062] According to an embodiment of this disclosure, the process of constructing a microwave frequency lookup table can be as follows: Before using the system for scanning magnetic imaging, a continuous-wave spectrum (CW) scan is performed on the first pixel position of the sample to be tested to obtain the values ​​of multiple fluorescent photon counts that correspond one-to-one with the multiple microwave frequencies irradiated at the first pixel position of the sample to be tested. The values ​​of multiple fluorescent photon counts at the first pixel position of the sample to be tested are used as the index of the microwave frequency lookup table, and the multiple microwave frequencies that correspond one-to-one with the values ​​of multiple fluorescent photon counts are used as the values ​​of the microwave frequency lookup table to obtain the microwave frequency lookup table.

[0063] According to an embodiment of this disclosure, the calculation process of the resonance frequency at the first test pixel position of the sample to be tested can be as follows: using multiple microwave frequencies irradiated at the first test pixel position of the sample to be tested as the abscissa, and using the number of multiple fluorescent photons corresponding one-to-one with the multiple microwave frequencies irradiated at the first test pixel position of the sample to be tested as the ordinate, a Lorentz curve is fitted, and the microwave frequency corresponding to the minimum ordinate on the Lorentz curve is the resonance frequency at the first test pixel position of the sample to be tested.

[0064] According to embodiments of this disclosure, the magnetic measurement algorithm module obtains the resonant frequency at the i-th pixel position and the preset frequency at the i+1-th pixel position of the sample based on the number of fluorescent photons of the i-th pixel corresponding to the digital fluorescence signal of the i-th pixel, the resonant frequency at the (i-1)-th pixel position of the sample, and a microwave frequency lookup table, including:

[0065] Find the number of fluorescent photons at the first test pixel position corresponding to the number of fluorescent photons of the i-th pixel in the microwave frequency lookup table, wherein the difference between the number of fluorescent photons of the i-th pixel and the number of fluorescent photons at the first test pixel position is within the photon count judgment threshold range.

[0066] Find the preset frequency value of the first pixel position to be tested, which corresponds to the number of fluorescent photons at the first pixel position to be tested in the microwave frequency lookup table;

[0067] The resonant frequency at the i-th pixel position of the sample under test is calculated based on the resonant frequency at the (i-1)th pixel position of the sample under test and the difference between the preset frequency value at the 1st pixel position and the preset frequency value at the i-th pixel position of the sample under test.

[0068] Based on the resonance frequency at the i-th pixel position of the sample to be tested, a preset frequency is selected for the (i+1)-th pixel position of the sample to be tested near this resonance frequency.

[0069] According to embodiments of this disclosure, by looking up a preset frequency value for the first pixel position of the sample to be tested, which corresponds to the number of fluorescent photons at the first pixel position of the sample to be tested, from a microwave frequency lookup table, and then calculating the resonance frequency at the i-th pixel position of the sample to be tested based on the resonance frequency at the (i-1)-th pixel position of the sample to be tested and the difference between the preset frequency value at the first pixel position of the sample to be tested and the preset frequency value at the i-th pixel position of the sample to be tested, the resonance frequency at the i-th pixel position of the sample to be tested can be calculated during the system scanning magnetic measurement process without fitting the data related to the calculation of the resonance frequency at the pixel position of the sample to be tested. This enables the system to quickly achieve quantitative large dynamic range magnetic imaging of the magnetic field.

[0070] According to embodiments of this disclosure, by selecting a preset frequency a preset number of times for the (i+1)th pixel position of the sample under test based on the resonance frequency at the i-th pixel position of the sample under test, a preset frequency is selected for each pixel position of the sample under test based on the resonance frequencies at adjacent pixel positions. This makes the magnitude of the selected preset frequency closer to the magnitude of the resonance frequency of the pixel position of the sample under test. When these preset frequencies are subsequently used to obtain data related to calculating the resonance frequency of the pixel position of the sample under test, the accuracy of the system in measuring the resonance frequency of the pixel position of the sample under test can be improved.

[0071] According to embodiments of this disclosure, by selecting a preset frequency for a preset number of times at the (i+1)th pixel position of the sample under test based on the resonant frequency at the i-th pixel position of the sample under test, the number of preset frequencies at the pixel position of the sample under test can be selected according to actual conditions. Compared with the magnetic measurement method in traditional magnetic imaging methods, the number of microwaves scanning the preset frequency at the pixel position of the sample under test can be reduced, thereby improving the efficiency of the magnetic imaging system.

[0072] According to embodiments of this disclosure, the photon count determination threshold can be, for example, (-400, 200), (-300, 250), or (-350, 350). The photon count determination threshold can be selected according to actual conditions, and embodiments of this disclosure do not limit the photon count determination threshold.

[0073] According to embodiments of this disclosure, the preset number of times can be, for example, 4, 6, or 10. The preset number of times can be selected according to actual circumstances, and embodiments of this disclosure do not limit the preset number of times.

[0074] According to embodiments of this disclosure, the photon count determination threshold can be stored in the parameter register of the magnetometry algorithm module.

[0075] Figure 2 A schematic diagram illustrating the determination of the resonant frequency at the position of the pixel to be tested in a sample according to an embodiment of the present disclosure.

[0076] Figure 3 The diagram illustrates a method for determining the preset frequency and fluorescence photon count of a pixel to be tested in a sample according to an embodiment of the present disclosure.

[0077] like Figure 2 As shown, the first curve is the Lorentz curve at the first pixel position of the sample under test, and the second curve is the Lorentz curve at any pixel position of the sample under test other than the first pixel position, for example, it can be the Lorentz curve at the second pixel position of the sample under test.

[0078] When the system begins scanning the sample for magnetic imaging, the magnetic measurement algorithm module can select four preset frequencies near the resonant frequency of the first pixel position of the sample for the second pixel position. The system uses a laser pulse sequence and microwave pulse sequences of the four preset frequencies to irradiate the second pixel position of the sample and processes the fluorescence emitted from the second pixel position to obtain the number of fluorescent photons of the second pixel corresponding to each of the four preset frequencies, thereby obtaining the number of fluorescent photons of the four second pixels.

[0079] The four preset frequencies at the second pixel position of the sample under test and the number of fluorescent photons of the second pixel corresponding to each of the four preset frequencies are as follows: Figure 3 As shown. Figure 3 The curve in the middle is Figure 2 The second curve in the diagram is the Lorentz curve at the second pixel position of the sample under test.

[0080] like Figure 3 As shown, the four preset frequencies at the second pixel position of the sample under test are f1 to f4, and the number of fluorescent photons of the second pixel corresponding to each of the four preset frequencies are P1 to P4.

[0081] Depend on Figure 3 It is known that when the Lorentz curve shifts left or right, the values ​​of P1 to P4 will deviate from their original symmetrical positions. To reduce the influence of noise on the fluorescence photon count, the preset frequency at the second pixel position of the sample under test can be used to find the fluorescence photon count near the waist of the Lorentz curve. The required screening parameters can be stored in the parameter register of the magnetic measurement algorithm module.

[0082] like Figure 2 As shown, when the magnetic field at the pixel position of the sample changes, causing the Loronic curve to shift to the right, Figure 2 In this context, P4 represents the number of fluorescent photons in the second pixel corresponding to the preset frequency f4. Based on the number of fluorescent photons P4 in the second pixel, it is possible to... Figure 2 The number of fluorescent photons P4′ of the first pixel is found in the microwave frequency lookup table corresponding to the first curve. At this time, the difference between P4 and P4′ is within the photon count judgment threshold (-400, 200). Figure 2 P4″ represents the number of fluorescent photons in the first pixel corresponding to the preset frequency f4.

[0083] Based on the number of fluorescent photons P4′ of the first pixel, the preset frequency f4′ of the first pixel corresponding to the number of fluorescent photons P4′ can be found in the microwave frequency lookup table. For each number of fluorescent photons, the frequency values ​​of the two first pixels to the left and right of the Lorentz curve will be found. The correct frequency value of the first pixel can be determined by the relative magnitude between the preset frequency f4′ of the first pixel and the preset frequency f4 of the second pixel.

[0084] At this point, the preset frequency difference between the preset frequency at the second pixel position of the sample under test and the preset frequency at the first pixel position of the sample under test is δ. k4 δ k4 =f4-f4′. Similarly, the preset frequency differences between the other preset frequencies at the second measured pixel position and the preset frequency at the first measured pixel position can be obtained. With four preset frequency differences obtained, the average of these four differences can be used as the difference δ between the resonant frequency at the second measured pixel position and the resonant frequency at the first measured pixel position of the sample. k The resonant frequency at the first pixel position of the sample under test is f. c In this case, the resonant frequency at the second pixel position of the sample under test is f. c +δ k Therefore, the system measurement result is the resonant frequency value of each pixel of the sample under test.

[0085] According to embodiments of this disclosure, the magnetic field information of each pixel of the sample under test can be obtained based on the relationship between the resonant frequency value of each pixel of the sample under test and the magnetic magnitude of each pixel of the sample under test.

[0086] According to the embodiments of this disclosure, since the number of fluorescent photons, preset frequency and resonance frequency of the first pixel of the sample to be tested are known, it is only necessary to obtain the difference in resonance frequency between the other pixels of the sample to be tested and the first pixel to be tested, so as to obtain the resonance frequency of each pixel of the sample to be tested, thereby improving the speed and efficiency of detecting the resonance frequency of each pixel of the sample to be tested.

[0087] According to embodiments of this disclosure, the magnetization algorithm module may also optionally incorporate other algorithms suitable for implementation in an FPGA. For example, a phase-locked loop demodulation method may be used.

[0088] According to embodiments of this disclosure, the phase-locked demodulation method is as follows: The fluorescence signal generated by the NV color center is modulated by scanning the microwave frequency; the signal is then orthogonally demodulated by the lock-in amplifier of the scanning digital signal processing unit to obtain the phase change of the fluorescence signal; and the resonant frequency change of the corresponding pixel in the sample is obtained based on the phase change. The preset frequency range of the scanning microwave is adjusted according to the new resonant frequency value, thereby achieving magnetic field measurement tracking. This algorithm can achieve rapid scanning magnetic imaging when the NV color center count rate is high, the system signal-to-noise ratio is high, and the modulation frequency reaches kHz.

[0089] According to embodiments of this disclosure, the quantum diamond atomic force microscope electronic control readout system provided herein enables synchronous control and signal readout of laser, microwave, and other equipment using a single system, featuring high equipment integration and good experimental method flexibility. Simultaneously, it performs real-time signal and data processing on the signals and data corresponding to each pixel position of the sample under test, resulting in short data transmission time and high synchronization, reducing experimental time costs and equipment maintenance difficulty. While ensuring system measurement accuracy and efficiency, it achieves rapid scanning magnetic imaging.

[0090] According to embodiments of this disclosure, since the magnetic measurement algorithm module can respond to the control signal of the system control readout module, it obtains the resonant frequency at the i-th pixel position and the preset frequency at the i+1-th pixel position of the sample based on the number of fluorescent photons of the i-th pixel corresponding to the digital fluorescence signal of the i-th pixel, the resonant frequency at the (i-1)-th pixel position of the sample, and a microwave frequency lookup table. This enables the system to quickly achieve quantitative large dynamic range magnetic imaging of the magnetic field. Moreover, the number of preset frequencies in the magnetic measurement algorithm module can be selected according to the actual situation. Compared with the magnetic measurement method in traditional magnetic imaging methods, this reduces the number of microwaves scanning the preset frequencies at the pixel positions of the sample, thereby improving the efficiency of the system's magnetic measurement imaging.

[0091] Figure 4 A schematic diagram of a magnetic measurement algorithm module according to an embodiment of the present disclosure is shown.

[0092] like Figure 4 As shown, the magnetic measurement algorithm module includes: a lookup table storage unit 21, a preset frequency calculation unit 22, and a parameter register 23.

[0093] The lookup table storage unit 21 is used to store the values ​​of multiple fluorescent photon counts at the first test pixel position of the sample to be tested, and multiple preset frequencies that correspond one-to-one with the values ​​of multiple fluorescent photon counts.

[0094] The preset frequency calculation unit 22 is used to obtain the resonance frequency at the i-th pixel position and the preset frequency at the i+1-th pixel position of the sample based on the number of fluorescent photons of the i-th pixel corresponding to the digital fluorescence signal of the i-th pixel, the resonance frequency at the (i-1)-th pixel position of the sample to be tested, and the microwave frequency lookup table.

[0095] The parameter register 23 is used to store the resonant frequency at the i-th pixel position of the sample to be tested and the preset frequency at the (i+1)-th pixel position of the sample to be tested.

[0096] According to embodiments of this disclosure, the parameter register is also used to store a photon count determination threshold.

[0097] According to an embodiment of this disclosure, before the preset frequency calculation unit performs calculations, the system control readout module transmits the number of fluorescent photons corresponding to the digital fluorescence signal calculated in the magnetometry digital signal processing unit to the preset frequency calculation unit.

[0098] According to an embodiment of this disclosure, after receiving a trigger signal from the system control readout module to perform calculations, the preset frequency calculation unit calculates the resonant frequency at the i-th pixel position and the preset frequency at the (i+1)-th pixel position of the sample under test. It then transmits the calculated resonant frequency and preset frequency to the system control readout module. The system control readout module transmits the resonant frequency at the i-th pixel position to the host computer and simultaneously transmits the preset frequency at the (i+1)-th pixel position to the magnetic field digital signal processing unit, initiating the measurement of the fluorescence signal at the (i+1)-th pixel position.

[0099] Figure 5 A schematic diagram of a magnetometer control and readout module according to an embodiment of the present disclosure is shown.

[0100] like Figure 5 As shown, the magnetic measurement control and readout module includes: a microwave generator unit 31, a sequence generator 32, and an analog-to-digital converter circuit 33.

[0101] The microwave generating unit 31 is used to control the microwave generator to emit microwaves of a stable preset frequency according to the preset frequency at the position of the i-th pixel to be tested of the sample.

[0102] The sequence generator 32 is used to convert laser light into a laser pulse sequence and microwave light of a preset frequency into a microwave pulse sequence of a preset frequency.

[0103] The analog-to-digital converter circuit 33 is used to acquire the analog fluorescence signal at the i-th pixel position of the quantum diamond probe on the sample to be tested, and convert the analog fluorescence signal into a digital fluorescence signal.

[0104] According to embodiments of this disclosure, the microwave generating unit, in response to a control signal from the system control readout module, controls the frequency switching of the microwave source via a communication bus to generate microwaves of different preset frequencies required by the system. This allows for the manipulation of the NV color center quantum state using microwaves of different preset frequencies. The control signal from the system control readout module, which the microwave generating unit responds to, includes a microwave trigger digital signal and a preset frequency setting digital signal.

[0105] According to embodiments of this disclosure, the sequence generator includes a level conversion circuit and an output driving circuit. Responding to a control signal from the system control readout module, the sequence generator reads in the laser emitted by the laser emitter, the microwave output from the microwave generating unit at different preset frequencies, and the sequence digital signals output from the digital sequence signal generating subunit for controlling the timing of the laser and microwave. It then outputs the laser pulse sequence and microwave pulse sequence required by the system, synchronously controlling the microwave and laser to be emitted in a specific timing sequence.

[0106] According to embodiments of this disclosure, the analog-to-digital conversion circuit can be implemented by a high-speed comparator or an analog-to-digital converter (ADC).

[0107] According to embodiments of this disclosure, the analog-to-digital converter (ADC) performs high / low level discrimination or sampling on the analog fluorescence signal converted by the photodetector, converting the analog fluorescence signal generated by the photodetector into a digital fluorescence signal. Then, in response to the control signal from the system control readout module, the ADC inputs the digital fluorescence signal to the scanning digital signal processing unit, which performs subsequent processing such as counting on the digital fluorescence signal. The analog fluorescence signal is... Figure 5 The photoelectric detection signal can be in the form of a fluorescence pulse signal or a photocurrent signal. The corresponding digital fluorescence signal can be in the form of a single-photon digital signal or a photocurrent digital signal. The embodiments of this disclosure do not limit the form of the photoelectric detection signal or the form of the digital fluorescence signal, and can be selected according to the actual situation.

[0108] According to an embodiment of this disclosure, during the microwave emission process, the system control readout module inputs a microwave trigger digital signal to the microwave emission unit based on the preset frequency at the i-th pixel position of the sample to be tested output by the magnetic digital signal processing unit, controls the timing of microwave emission, and inputs a preset frequency setting digital signal to the microwave emission unit to control the microwave emission of microwaves at the preset frequency.

[0109] According to embodiments of this disclosure, the system further includes a scanning control module.

[0110] The scanning control module is used to respond to the control signal from the system control readout module and control the quantum diamond probe of the quantum diamond atomic force microscope to move to the i-th pixel position of the sample to be tested.

[0111] Figure 6 A schematic diagram of a scanning control module according to an embodiment of the present disclosure is shown.

[0112] like Figure 6 As shown, the scanning control module 4 includes: a displacement stage stability detection circuit 41 and an analog input / output unit 42.

[0113] The displacement stage stabilization detection circuit 41 is used to process the probe analog signal, output the probe digital signal to the system control readout module, and output the probe excitation analog signal to the quantum diamond probe of the quantum diamond atomic force microscope. The probe analog signal is an analog voltage signal corresponding to the force between the quantum diamond probe of the quantum diamond atomic force microscope and the i-th pixel to be tested of the sample.

[0114] The analog input / output unit 42 is used to output a digital signal of the displacement stage to the system control readout module based on the displacement stage analog signal related to the position of the displacement stage where the quantum diamond probe is located, and to output a displacement stage movement analog signal to the displacement stage to control the movement of the displacement stage. The displacement stage movement analog signal includes a vertical movement analog signal and a horizontal movement analog signal of the displacement stage.

[0115] like Figure 6 As shown, the displacement stage stability detection circuit includes a high-speed ADC, a high-speed digital-to-analog converter (DAC), and peripheral analog circuits.

[0116] A high-speed ADC is used for state readback of the quantum diamond probe in a quantum diamond atomic force microscope. Specifically, the high-speed ADC processes the input analog probe signal and outputs a digital probe signal to the system control readout module. The analog probe signal is... Figure 6 The probe output signal, the probe digital signal is Figure 6 The input signal of the lock-in amplifier in the circuit.

[0117] A high-speed DAC is used to output a probe excitation analog signal to the quantum diamond probe of a quantum diamond atomic force microscope. Specifically, the high-speed DAC processes the AND probe digital signal output from the system control readout module to output the probe excitation analog signal to the quantum diamond probe of the quantum diamond atomic force microscope. The AND probe digital signal output from the system control readout module is... Figure 6The output signal of the lock-in amplifier in the middle.

[0118] like Figure 6 As shown, the analog input / output unit includes a high-precision ADC, a high-precision DAC, and peripheral analog circuitry.

[0119] A high-precision ADC is used for state readback of the displacement stage. Specifically, the high-precision ADC outputs a digital signal of the displacement stage to the system control readout module based on the analog signal of the displacement stage related to the position of the quantum diamond probe. The analog signal of the displacement stage is... Figure 6 The output voltage of the displacement stage, the digital signal of the displacement stage is Figure 6 The displacement stage reads back the digital signal.

[0120] The high-precision DAC outputs an analog voltage to control the movement of the displacement stage. Specifically, the high-precision DAC processes the digital voltage signal related to the digital signal of the displacement stage output from the system control readout module, and outputs a displacement stage movement analog signal to control the movement of the displacement stage. The digital voltage signal related to the digital signal of the displacement stage output from the system control readout module is... Figure 6 The scanning control digital signal and the displacement stage movement analog signal are... Figure 6 The control voltage of the displacement stage.

[0121] According to embodiments of this disclosure, the displacement stage stability detection circuit and the circuitry in the analog input / output unit are configured by a scanning digital signal processing unit. The displacement stage stability detection circuit inputs the generated probe digital signal into a lock-in amplifier in the scanning digital signal processing unit for calculation. The calculated digital voltage signal is configured into the circuitry in the analog input / output unit, which controls the displacement stage where the quantum diamond probe is located, thereby stabilizing the distance between the probe and the sample under test.

[0122] Figure 7 A schematic diagram of a system control readout module according to an embodiment of the present disclosure is shown.

[0123] like Figure 7 As shown, the system control readout module includes: a scanning digital signal processing unit 12, a magnetic measurement digital signal processing unit 13, and a central logic processing unit 11.

[0124] The scanning digital signal processing unit 12 is used to process the displacement stage digital signal related to the position of the displacement stage where the quantum diamond probe is located, and generate the displacement stage movement digital signal that controls the movement of the displacement stage where the quantum diamond probe is located. The displacement stage movement digital signal includes the vertical movement digital signal and the horizontal movement digital signal of the displacement stage.

[0125] The magnetic digital signal processing unit 13 is used to process the preset frequency of the microwave pulse sequence corresponding to the i-th pixel position of the sample under test and the digital fluorescence signal at the i-th pixel position of the sample under test, and output the number of fluorescence photons.

[0126] The central logic processing unit 11 is used to control the signal transmission between the scanning digital signal processing unit, the magnetometry digital signal processing unit, and the magnetometry algorithm module.

[0127] like Figure 7 As shown, the central logic processing unit is implemented through hardware logic design in the FPGA. The central logic processing unit is used for system parameter configuration and status readback of various parts of the system, that is, to trigger and control the scanning digital signal processing unit and the magnetometer digital signal processing unit, and to communicate with the host computer.

[0128] According to embodiments of this disclosure, the central logic processing unit stores the position parameters of the pixels to be tested in the sample and the preset frequency parameters of the scanning microwave.

[0129] According to embodiments of this disclosure, during the commencement of magnetic imaging scanning, the central logic processing unit loads position parameters and preset frequency parameters into the scanning digital signal processing unit and the magnetometry digital signal processing unit, respectively. Each time the magnetometry digital signal processing unit completes a fluorescence photon count readback, the central logic processing unit triggers a preset frequency switch for the microwave, and also triggers the generation of a new laser pulse sequence and a microwave pulse sequence.

[0130] According to an embodiment of this disclosure, after scanning the pixel to be tested of a sample to be tested is completed, the central logic processing unit controls the scanning digital signal processing unit to send a trigger signal to the scanning control module, thereby controlling the displacement stage where the quantum diamond probe is located to move to the position of the pixel to be tested of the next sample to be tested.

[0131] According to an embodiment of this disclosure, the central logic processing unit can be connected to the magnetometry algorithm module, in which case the preset frequency parameters of the scanning microwave are calculated in real time by the magnetometry algorithm module.

[0132] like Figure 7 As shown, the scanning digital signal processing unit includes: a digital lock-in amplifier 121, a feedback calculation subunit 122, and a digital scanning waveform generation subunit 123.

[0133] The digital lock-in amplifier 121 is used to measure the probe digital signal, output the lock-in amplified probe digital signal, and output the probe excitation digital signal to excite the quantum diamond probe to vibrate. The probe digital signal is a digital voltage signal corresponding to the force between the quantum diamond probe of the quantum diamond atomic force microscope and the i-th pixel position of the sample to be tested.

[0134] The feedback calculation subunit 122 is used to perform feedback calculation on the phase-locked amplified probe digital signal to generate a vertical movement digital signal of the displacement stage that controls the vertical movement of the displacement stage where the quantum diamond probe is located.

[0135] The digital scanning waveform generation subunit 123 is used to output a digital signal for the vertical movement of the displacement stage and a digital signal for the horizontal movement of the displacement stage, which controls the quantum diamond probe to move in the horizontal direction according to a preset movement path. The preset movement path represents the path for scanning each pixel position of the sample to be tested.

[0136] like Figure 7 As shown, the digital lock-in amplifier responds to the control signal of the system control readout module, obtains the probe digital signal from the scan control module, performs lock-in amplification on the probe digital signal, outputs the lock-in amplified digital probe signal, and outputs the probe excitation digital signal to excite the quantum diamond probe to vibrate.

[0137] According to an embodiment of this disclosure, the digital lock-in amplifier responds to the control signal of the system control readout module by inputting the lock-in amplified probe digital signal into the feedback calculation subunit. The feedback calculation subunit performs feedback calculation on the lock-in amplified probe digital signal to generate a vertical movement digital signal of the displacement stage that controls the displacement stage where the quantum diamond probe is located to move in the vertical direction.

[0138] According to embodiments of this disclosure, a digital scanning waveform generation subunit generates a digital voltage signal that controls the movement of the displacement stage where the quantum diamond probe is located.

[0139] According to embodiments of this disclosure, for a tuning fork type atomic force microscope, the quantum diamond probe includes a tuning fork, and the feedback calculation subunit can be an integral-differential-control system (PID). A lock-in amplifier is used to drive and acquire the tuning fork vibration signal, and input the tuning fork vibration signal into the PID for feedback calculation to obtain a digital signal for the vertical movement of the displacement stage, thereby controlling the displacement stage where the quantum diamond probe is located to move in the vertical direction.

[0140] According to embodiments of this disclosure, the PID feedback mode can be vibration amplitude feedback, and the feedback calculation can be PI closed-loop feedback.

[0141] According to the embodiments of this disclosure, under normal non-contact conditions, as the vibration amplitude of the tuning fork decreases, the distance between the quantum diamond probe and the sample to be tested decreases accordingly. In order to make the quantum diamond probe and the sample to be tested close enough, a target amplitude smaller than the free vibration amplitude can be preset. The difference between the actual vibration amplitude of the tuning fork obtained by the lock-in amplifier in real time and the target amplitude is e(t). The PID module can calculate the proportional and integral terms based on e(t) to obtain the adjustment amount Δf(t) that controls the displacement stage where the quantum diamond probe is located to move in the vertical direction. The calculation formula of Δf(t) is shown in formula (1).

[0142]

[0143] Among them, K p K i These are the proportional and integral term coefficients, respectively. Δf(t) is the analog control voltage used to adjust the vertical movement of the displacement stage containing the quantum diamond probe.

[0144] According to embodiments of this disclosure, the distance between the quantum diamond probe and the sample to be tested can be adjusted using Δf(t) to stabilize the vibration amplitude of the tuning fork, i.e., to stabilize the distance between the quantum diamond probe and the sample to be tested.

[0145] According to embodiments of this disclosure, the PID feedback mode can also use vibration frequency feedback or amplitude-frequency feedback of a double phase-locked loop structure.

[0146] According to embodiments of this disclosure, a digital lock-in amplifier combined with a feedback computation subunit enables stability control of a quantum diamond probe. Alternatively, the digital lock-in amplifier combined with the feedback computation subunit can be implemented using a separate external device. In this case, the digital lock-in amplifier combined with the feedback computation subunit only performs real-time stability control of the probe and does not participate in the scanning magnetic imaging process.

[0147] like Figure 7 As shown, the magnetic measurement digital signal processing unit includes: a counting / acquisition subunit 131, a microwave frequency cutting subunit 132, and a digital sequence signal generation subunit 133.

[0148] The counting / acquisition subunit 131 is used to count the digital fluorescence signal to obtain the number of fluorescence photons.

[0149] The microwave frequency switching subunit 132 is used to generate a microwave frequency digital signal that controls the switching of microwaves to the preset frequency according to the preset frequency.

[0150] The digital sequence signal generation subunit 133 is used to generate a sequence of digital signals that control the timing of microwave pulses and laser pulses.

[0151] According to embodiments of this disclosure, the commonly used magnetometry method for scanning magnetic imaging is the CW spectroscopy method, which requires the acquisition of digital fluorescence signals of NV color centers under microwave irradiation at different microwave frequencies.

[0152] like Figure 7 As shown, the counting / acquisition subunit counts the digital fluorescence signal output by the analog-to-digital conversion circuit in the magnetometry control and readout module to obtain the number of fluorescence photons, and outputs the number of fluorescence photons to the magnetometry algorithm module in response to the control signal of the system control readout module.

[0153] like Figure 7 As shown, the microwave frequency switching subunit receives the preset frequency output by the magnetometry algorithm module, and generates a microwave frequency digital signal to control the microwave to switch to the preset frequency according to the preset frequency. The microwave frequency digital signal is in the form of a digital voltage signal and includes a microwave trigger digital signal and a preset frequency setting digital signal.

[0154] like Figure 7 As shown, the digital sequence signal generation subunit is used to generate sequential digital signals that control the timing of microwave pulses and laser pulses. The digital sequence signals are in the form of digital voltage signals, sequential digital microwave pulse signals, and laser pulse signals. The system control readout module outputs the sequential digital signals to the sequence generator, controlling the sequence generator to output high-precision microwave pulse sequences and laser pulse sequences.

[0155] According to embodiments of this disclosure, the system control readout module and the magnetometry algorithm module can be integrated into an FPGA.

[0156] According to embodiments of this disclosure, since the system control readout module and the magnetic measurement algorithm module can be integrated into an FPGA, the system's control readout logic, high-precision synchronous timing control, high-speed parallel computing, and real-time data processing are implemented in hardware, thereby achieving rapid magnetic imaging of the sample under test. Compared with traditional software-controlled discrete devices, this method improves system integration, reduces equipment maintenance difficulty, reduces control readout time consumption, and improves system operating efficiency.

[0157] Embodiments of this disclosure provide an electronically controlled readout method for a quantum diamond atomic force microscope, comprising:

[0158] In response to the control signal from the system control readout module, a laser pulse sequence and a microwave pulse sequence of a preset frequency are emitted to the quantum diamond probe located at the i-th pixel position of the sample to be tested. Then, the analog fluorescence signal of the quantum diamond probe at the i-th pixel position of the sample to be tested is acquired, and the digital fluorescence signal of the i-th pixel is output, where i is an integer greater than or equal to 2.

[0159] In response to the control signal from the system control readout module, based on the number of fluorescent photons of the i-th pixel corresponding to the digital fluorescence signal of the i-th pixel, the resonance frequency at the (i-1)-th pixel position of the sample under test, and the microwave frequency lookup table, the resonance frequency at the i-th pixel position of the sample under test and the preset frequency at the (i+1)-th pixel position of the sample under test are obtained. The index of the microwave frequency lookup table is the value of multiple fluorescent photons at the first pixel position of the sample under test, the value of the microwave frequency lookup table is multiple preset frequencies that correspond one-to-one with the values ​​of multiple fluorescent photons, and the resonance frequency is the frequency value at the lowest point of the Lorentz curve fitted by the number of fluorescent photons and the preset frequency corresponding to each pixel position of the sample under test.

[0160] It should be noted that the quantum diamond atomic force microscope electronic control readout system part in the embodiments of this disclosure corresponds to the quantum diamond atomic force microscope electronic control readout method part in the embodiments of this disclosure. For the specific description of the quantum diamond atomic force microscope electronic control readout method part, please refer to the quantum diamond atomic force microscope electronic control readout system part, and it will not be repeated here.

[0161] Those skilled in the art will understand that the features described in the various embodiments and / or claims of this disclosure can be combined and / or combined in various ways, even if such combinations or combinations are not explicitly described in this disclosure. In particular, the features described in the various embodiments and / or claims of this disclosure can be combined and / or combined in various ways without departing from the spirit and teachings of this disclosure, and all such combinations and / or combinations fall within the scope of this disclosure.

[0162] The embodiments of this disclosure have been described above. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of this disclosure. Although various embodiments have been described above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination. The scope of this disclosure is defined by the appended claims and their equivalents. Various substitutions and modifications can be made by those skilled in the art without departing from the scope of this disclosure, and all such substitutions and modifications should fall within the scope of this disclosure.

Claims

1. A quantum diamond atomic force microscope electronic control reading system, comprising: a system control reading module, a magnetic measurement algorithm module, and a magnetic measurement control and reading module; the magnetic measurement control and reading module is configured to, in response to a control signal of the system control reading module, emit a laser pulse sequence and a microwave pulse sequence of a preset frequency to a quantum diamond probe located at an i-th pixel position of a sample to be measured, and then collect an analog fluorescence signal of the quantum diamond probe at the i-th pixel position of the sample to be measured, and output a digital fluorescence signal of the i-th pixel, wherein i is an integer greater than or equal to 2; the magnetic measurement algorithm module is configured to, in response to a control signal of the system control reading module, obtain a resonance frequency at the i-th pixel position of the sample to be measured and a preset frequency at an i+1-th pixel position of the sample to be measured according to a fluorescence photon number of the i-th pixel corresponding to the digital fluorescence signal of the i-th pixel, a resonance frequency at an i-1-th pixel position of the sample to be measured, and a microwave frequency lookup table, wherein an index of the microwave frequency lookup table is a value of a plurality of fluorescence photon numbers at a first pixel position of the sample to be measured, a value of the microwave frequency lookup table is a plurality of preset frequencies corresponding to the value of the plurality of fluorescence photon numbers one by one, and the resonance frequency is a frequency value at a lowest point of a Lorentz curve fitted by the fluorescence photon number and the preset frequency corresponding to each pixel position of the sample to be measured respectively.

2. The system of claim 1, wherein, the magnetic measurement algorithm module comprises: a lookup table storage unit configured to store the value of the plurality of fluorescence photon numbers at the first pixel position of the sample to be measured, and the plurality of preset frequencies corresponding to the value of the plurality of fluorescence photon numbers one by one; a preset frequency calculation unit configured to obtain the resonance frequency at the i-th pixel position of the sample to be measured and the preset frequency at the i+1-th pixel position of the sample to be measured according to the fluorescence photon number of the i-th pixel corresponding to the digital fluorescence signal of the i-th pixel, the resonance frequency at the i-1-th pixel position of the sample to be measured, and the microwave frequency lookup table; a parameter register configured to store the resonance frequency at the i-th pixel position of the sample to be measured and the preset frequency at the i+1-th pixel position of the sample to be measured.

3. The system of claim 1, wherein, the magnetic measurement control and reading module comprises: a microwave generation unit configured to control a microwave generator to emit microwave of a stable preset frequency according to the preset frequency at the i-th pixel position of the sample to be measured; a sequence generator configured to convert laser into the laser pulse sequence, and convert the microwave of the preset frequency into a microwave pulse sequence of the preset frequency; an analog-to-digital conversion circuit configured to collect an analog fluorescence signal of the quantum diamond probe at the i-th pixel position of the sample to be measured, and convert the analog fluorescence signal into the digital fluorescence signal.

4. The system of claim 1, wherein, the system further comprises a scanning control module; the scanning control module is configured to, in response to a control signal of the system control reading module, control a quantum diamond probe of the quantum diamond atomic force microscope to move to the i-th pixel position of the sample to be measured.

5. The system of claim 4, wherein, The scanning control module comprises: A displacement table stability detection circuit, configured to process a probe analog signal, output a probe digital signal to the system control readout module, and output a probe excitation analog signal to a quantum diamond probe of the quantum diamond atomic force microscope, wherein the probe analog signal is an analog voltage signal corresponding to an interaction force between the quantum diamond probe of the quantum diamond atomic force microscope and an i-th to-be-measured pixel of the to-be-measured sample; An analog input / output unit, configured to output a displacement table digital signal to the system control readout module according to a displacement table analog signal related to a position of a displacement table on which the quantum diamond probe is located, and output a displacement table movement analog signal for controlling the displacement table to move to the displacement table, wherein the displacement table movement analog signal comprises a displacement table vertical movement analog signal and a displacement table horizontal movement analog signal.

6. The system of claim 1, wherein, The system control readout module comprises: A scanning digital signal processing unit, configured to process the displacement table digital signal related to the position of the displacement table on which the quantum diamond probe is located, and generate a displacement table movement digital signal for controlling the displacement table on which the quantum diamond probe is located to move, wherein the displacement table movement digital signal comprises a displacement table vertical movement digital signal and a displacement table horizontal movement digital signal; A magnetic measurement digital signal processing unit, configured to output the preset frequency of the microwave pulse sequence corresponding to the i-th to-be-measured pixel position of the to-be-measured sample, and process the digital fluorescence signal at the i-th to-be-measured pixel position of the to-be-measured sample to output a fluorescence photon number; A central logic processing unit, configured to control signal transmission among the scanning digital signal processing unit, the magnetic measurement digital signal processing unit, and the magnetic measurement algorithm module.

7. The system of claim 6, wherein, The scanning digital signal processing unit comprises: A digital lock-in amplifier, configured to measure the probe digital signal, output a lock-in amplified probe digital signal, and output a probe excitation digital signal for exciting vibration of the quantum diamond probe, wherein the probe digital signal is a digital voltage signal corresponding to an interaction force between the quantum diamond probe of the quantum diamond atomic force microscope and the i-th to-be-measured pixel position of the to-be-measured sample; A feedback calculation subunit, configured to perform feedback calculation on the lock-in amplified probe digital signal to generate a displacement table vertical movement digital signal for controlling the displacement table on which the quantum diamond probe is located to move in a vertical direction; A digital scanning waveform generation subunit, configured to output the displacement table vertical movement digital signal and a displacement table horizontal movement digital signal for controlling the displacement table on which the quantum diamond probe is located to move in a horizontal direction according to a preset movement path, wherein the preset movement path represents a path for scanning each pixel position of the to-be-measured sample.

8. The system of claim 6, wherein, The magnetic measurement digital signal processing unit comprises: A counting / acquisition subunit, configured to count the digital fluorescence signal to obtain a fluorescence photon number; A microwave frequency switching subunit, configured to generate a microwave frequency digital signal for controlling a microwave switch to switch to the preset frequency according to the preset frequency; and A magnetic measurement algorithm module, configured to output a magnetic measurement algorithm digital signal for controlling the magnetic measurement digital signal processing unit to perform magnetic measurement on the to-be-measured sample. A digital sequence signal generating subunit is configured to generate a sequence digital signal for controlling the generation timing of the microwave pulse sequence and the laser pulse sequence.

9. The system of claim 1, wherein, The system control reading module and the magnetic measurement algorithm module can be integrated in an FPGA.

10. A quantum diamond atomic force microscope electronic control reading method, comprising, In response to a control signal of a system control readout module, a laser pulse sequence and a microwave pulse sequence of a preset frequency are emitted to the quantum diamond probe located at an i-th to-be-measured pixel position of a to-be-measured sample, and then an analog fluorescence signal of the quantum diamond probe at the i-th to-be-measured pixel position of the to-be-measured sample is collected, and a digital fluorescence signal of the i-th pixel is output, wherein i is an integer greater than or equal to 2; In response to the control signal of the system control reading module, the resonance frequency of the i-th to-be-measured pixel position of the to-be-measured sample and the preset frequency of the i+1-th to-be-measured pixel position of the to-be-measured sample are obtained according to the fluorescence photon number of the i-th pixel corresponding to the digital fluorescence signal of the i-th pixel, the resonance frequency of the i-1-th to-be-measured pixel position of the to-be-measured sample, and a microwave frequency lookup table, wherein the index of the microwave frequency lookup table is the value of the plurality of fluorescence photon numbers of the first to-be-measured pixel position of the to-be-measured sample, the value of the microwave frequency lookup table is a plurality of preset frequencies corresponding to the plurality of fluorescence photon number values, and the resonance frequency is the frequency value at the lowest point of the Lorentz curve fitted with the fluorescence photon number and the preset frequency corresponding to each to-be-measured pixel position of the to-be-measured sample.

Images