Wide-field dynamic magnetic imaging device and method

Abstract

The present disclosure provides a wide-field dynamic magnetic imaging device and method, which includes: a probe assembly including a diamond containing NV color centers; a microwave magnetic field assembly adapted to generate a uniform microwave field and a uniform bias magnetic field near the diamond to regulate the spin energy level and quantum state evolution process of the diamond; a laser modulation assembly adapted to output an initial uniform pulse laser to excite the diamond to emit fluorescence; a stripe light modulation assembly adapted to modulate the initial uniform pulse laser to output a stripe pulse laser so that the fluorescence emitted by the diamond is stripe fluorescence; or to modulate the fluorescence emitted by the diamond into stripe fluorescence; a fluorescence detection assembly adapted to perform spatial imaging of the stripe fluorescence to obtain magnetic field information of a sample to be tested, thereby obtaining an initial magnetic image of the sample to be tested; and a data processing assembly adapted to perform Fourier transform and inverse Fourier transform processing on the initial magnetic image to obtain a first magnetic image.

Description

Technical Field

[0001] At least one embodiment of the present disclosure relates to the technical field of wide-field quantum magnetic imaging, and more specifically to a wide-field dynamic magnetic imaging device and method. Background Art

[0002] NV color centers are atomic-scale point defects in diamond. Their robust room-temperature properties have led to applications in biological systems, integrated circuits, materials science, earth science, positioning and navigation, quantum information, and other fields. Quantum diamond microscopy utilizes optical initialization and readout of NV electron spin states to simultaneously measure the spatial distribution of multiple physical parameters, such as the vector magnetic field. Due to their small size, NV color centers can be placed close to the sample under test, enabling high-spatial-resolution magnetic field measurements.

[0003] Quantum diamond microscopy (QDM) technology has advanced rapidly over the past decade, with measurement bandwidths gradually expanding from static magnetic field measurements (DC) to dynamic magnetic field imaging (kHz). To acquire wide-field magnetic field images, QDM uses a camera (such as a charge-coupled device (CCD) or complementary metal-oxide-semiconductor (CMOS)) to collect the fluorescence of NV color centers, which carry electromagnetic signals. The camera's readout speed also determines the upper limit of QDM's temporal resolution (~10 ms), limiting the technique's ability to detect high-frequency dynamic signals. To meet the demands of dynamic magnetic imaging, researchers have recently employed lock-in cameras for fluorescence collection and imaging within QDM, achieving temporal resolutions as high as 0.4 ms. However, lock-in cameras require high NV fluorescence intensity, and temporal resolution is highly dependent on fluorescence intensity. For example, in this work, to achieve a temporal resolution of 0.4 ms, a high NV color center density (approximately 0.1-1 ppm) and a thickness of 40 microns were used, resulting in a spatial resolution far exceeding the optical diffraction limit. This makes the technology difficult to apply in low-light scenarios. For example, when high spatial resolution is required, the thickness of the NV center is only tens of nanometers to micrometers. At this time, the number of photoelectrons caused by the NV center fluorescence on the millisecond time scale is difficult to meet the detection threshold of the phase-locked camera, so it is difficult to achieve high temporal resolution.

[0004] In existing quantum diamond microscopy technology, under the requirement of high spatial resolution, the thickness of the NV center is only tens of nanometers to micrometers. At this time, the number of photoelectrons caused by NV center fluorescence on the millisecond time scale is difficult to meet the detection threshold of the phase-locked camera, making it difficult to achieve sub-millisecond to microsecond time-resolved measurement of high-frequency dynamic signals under the requirement of high spatial resolution. Summary of the Invention

[0005] To solve at least one of the above-mentioned and other technical problems in the prior art, the present disclosure provides a wide-field dynamic magnetic imaging device and method, which can achieve sub-millisecond to microsecond time-resolved measurement of high-frequency dynamic signals under the requirement of high spatial resolution.

[0006] According to one aspect of the present disclosure, a wide-field dynamic magnetic imaging device is provided, comprising:

[0007] A probe assembly including a diamond containing NV color centers;

[0008] A microwave magnetic field assembly, adapted to generate a uniform microwave field and a uniform bias magnetic field near the diamond to regulate the spin energy level and quantum state evolution of the diamond;

[0009] a laser modulation component adapted to output an initial uniform pulsed laser to excite the diamond to emit fluorescence, wherein the fluorescence includes magnetic field information of the sample to be measured;

[0010] a stripe light modulation component adapted to modulate the initial uniform pulse laser to output a stripe pulse laser, so that the fluorescence emitted by the diamond is stripe fluorescence; or to directly modulate the fluorescence emitted by the diamond into stripe fluorescence;

[0011] a fluorescence detection component adapted to perform spatial imaging of the stripe fluorescence to obtain magnetic field information of the sample to be tested, and further obtain an initial magnetic image of the sample to be tested; and

[0012] a data processing component adapted to perform Fourier transform and inverse Fourier transform on the initial magnetic image to obtain a first magnetic image;

[0013] The initial magnetic image includes a two-dimensional real-space image obtained by superimposing sub-two-dimensional real-space images obtained at multiple moments, and the first magnetic image includes multiple sub-two-dimensional real-space images corresponding to the multiple moments.

[0014] According to an embodiment of the present disclosure, a microwave magnetic field component is provided to generate a uniform microwave field and a uniform bias magnetic field near a diamond containing NV color centers included in a probe component to regulate the spin energy level and quantum state evolution process of the diamond; a laser modulation component is provided to output an initial uniform pulsed laser to excite the diamond to emit fluorescence, and the fluorescence includes magnetic field information of the sample to be tested; a stripe light modulation component is provided to modulate the initial uniform pulsed laser to output a stripe pulsed laser so that the fluorescence emitted by the diamond is stripe fluorescence; or the stripe light modulation component modulates the fluorescence emitted by the diamond into stripe fluorescence; a fluorescence detection component is provided to perform spatial imaging of the stripe fluorescence to obtain magnetic field information of the sample to be tested, and thereby obtain an initial magnetic image of the sample to be tested; and a data processing component is provided to perform Fourier transform and inverse Fourier transform on the initial magnetic image to obtain a first magnetic image; the initial magnetic image includes a two-dimensional real-space image obtained by superimposing sub-two-dimensional real-space images obtained at multiple moments, and the first magnetic image includes multiple sub-two-dimensional real-space images corresponding to the multiple moments. The present disclosure realizes sub-millisecond to microsecond time-resolved measurement of high-frequency dynamic signals under the requirement of high spatial resolution through the mutual cooperation between various components in a wide-field dynamic magnetic imaging device. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The above contents and other objects, features and advantages of the present disclosure will become more apparent through the following description of the embodiments of the present disclosure with reference to the accompanying drawings, in which:

[0016] Figure 1 Schematically illustrates an experimental sequence diagram of high-speed signal acquisition achieved by Fourier k-space encoding in a wide-field dynamic magnetic imaging device according to an embodiment of the present disclosure;

[0017] Figure 2 The following schematically shows the working principle diagram of the probe assembly in the wide-field dynamic magnetic imaging device according to an embodiment of the present disclosure;

[0018] Figure 3 Schematically shows the relative positions of a diamond containing NV color centers and a uniform radiation structure in a probe assembly in a wide-field dynamic magnetic imaging device according to an embodiment of the present disclosure;

[0019] Figure 4 Schematically shows a block diagram of a microwave magnetic field component in a wide-field dynamic magnetic imaging device according to an embodiment of the present disclosure;

[0020] Figure 5 Schematically shows a block diagram of a laser modulation component in a wide-field dynamic magnetic imaging device according to an embodiment of the present disclosure;

[0021] Figure 6 Schematically shows a block diagram of a fringe light modulation component in a wide-field dynamic magnetic imaging device according to another embodiment of the present disclosure;

[0022] Figure 7 A schematic diagram illustrating the principle of modulating stripe light by a stripe light modulation component in a wide-field dynamic magnetic imaging device according to an embodiment of the present disclosure is shown;

[0023] Figure 8 Schematically shows a block diagram of a fluorescence detection component in a wide-field dynamic magnetic imaging device according to an embodiment of the present disclosure;

[0024] Figure 9 Schematically shows a light path diagram for generating and collecting fringe fluorescence in a wide-field dynamic magnetic imaging device according to an embodiment of the present disclosure;

[0025] Figure 10 Schematically shows a light path diagram for generating and collecting fringe fluorescence in a wide-field dynamic magnetic imaging device according to another embodiment of the present disclosure;

[0026] Figure 11 The following schematically shows the working principle of the temperature control component in the wide-field dynamic magnetic imaging device according to an embodiment of the present disclosure;

[0027] Figure 12 A diagram schematically illustrates the positional relationship between a position adjustment component, a probe component, and a sample to be measured in a wide-field dynamic magnetic imaging device according to an embodiment of the present disclosure;

[0028] Figure 13 A flow chart schematically illustrates a wide-field dynamic magnetic imaging method according to an embodiment of the present disclosure; and

[0029] Figure 14 The flowchart schematically shows a method for wide-field dynamic magnetic imaging according to an embodiment of the present disclosure, which uses a data processing component to perform Fourier transform and inverse Fourier transform on an initial magnetic image to obtain a first magnetic image.

[0030] In the above drawings, the meanings of the reference numerals are as follows:

[0031] 1-Probe assembly;

[0032] 101- Diamond containing NV color center;

[0033] 102-uniform radiation structure;

[0034] 2-Microwave magnetic field assembly;

[0035] 201-microwave source;

[0036] 202-microwave beam splitter;

[0037] 203-microwave switch;

[0038] 204-microwave combiner;

[0039] 205-Microwave amplifier;

[0040] 206-Isolator;

[0041] 207-impedance matching;

[0042] 208-magnetic field source;

[0043] 3-Laser modulation component;

[0044] 301-Laser;

[0045] 302-first half-wave plate;

[0046] 303-Acousto-optic modulator group;

[0047] 304-lens group;

[0048] 3041-first convex lens;

[0049] 3042-second convex lens;

[0050] 305-beam shaper;

[0051] 306-second half-wave plate;

[0052] 307-first reflection component;

[0053] 3071-first reflector;

[0054] 3072-second reflector;

[0055] 4-striped light modulation component;

[0056] 401-Digital Micromirror Device;

[0057] 402-first lens;

[0058] 403-Filter;

[0059] 404-second lens;

[0060] 5-fluorescence detection component;

[0061] 501-imaging lens;

[0062] 502-multi-stage filter;

[0063] 503-fluorescence detector;

[0064] 6-Data processing component;

[0065] 7-sample to be tested;

[0066] 8-substrate;

[0067] 9- Temperature control component;

[0068] 901-Temperature monitor;

[0069] 902-temperature control box;

[0070] 903-temperature controller;

[0071] 10-Objective lens;

[0072] 11- first focusing lens;

[0073] 12- third reflector;

[0074] 13- dichroic mirror;

[0075] 14-achromatic lens;

[0076] 15-position adjustment component;

[0077] 151- Z-axis position adjustment device;

[0078] 152-two-axis position adjustment device;

[0079] 153-three-axis position adjustment device;

[0080] 1531-Three-axis large-range position adjustment device;

[0081] 1532-Three-axis small-range position adjustment device. DETAILED DESCRIPTION

[0082] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present disclosure. In the detailed description below, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of the embodiments of the present disclosure. However, it is apparent that one or more embodiments may also be implemented without these specific details. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessary confusion of the concepts of the present disclosure.

[0083] The terms used herein are only for describing specific embodiments and are not intended to limit the present disclosure. The terms "comprise," "include," etc. used herein indicate the presence of the features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0084] 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 should be interpreted as having a meaning consistent with the context of this specification and should not be interpreted in an idealized or overly rigid manner.

[0085] When expressions such as "at least one of A, B, and C, etc." are used, they should generally be interpreted in accordance with the meaning commonly understood by those skilled in the art (for example, "a system having at least one of A, B, and C" should include but is not limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.).

[0086] In existing quantum diamond microscopy technology, under the requirement of high spatial resolution, the thickness of the NV center is only tens of nanometers to micrometers. At this time, the number of photoelectrons caused by NV center fluorescence on the millisecond time scale is difficult to meet the detection threshold of the phase-locked camera, making it difficult to achieve sub-millisecond to microsecond time-resolved measurement of high-frequency dynamic signals under the requirement of high spatial resolution.

[0087] In view of this, the present disclosure provides a wide-field dynamic magnetic imaging device, which generates a uniform microwave field and a uniform bias magnetic field near a diamond containing NV color centers included in a probe assembly by setting a microwave magnetic field component to regulate the spin energy level and quantum state evolution process of the diamond; a laser modulation component is set to output an initial uniform pulse laser to excite the diamond to emit fluorescence, and the fluorescence includes magnetic field information of the sample to be measured; a stripe light modulation component is set to modulate the initial uniform pulse laser to output a stripe pulse laser so that the fluorescence emitted by the diamond is stripe fluorescence; or the stripe light modulation component modulates the fluorescence emitted by the diamond into stripe fluorescence; a fluorescence detection component is set to perform spatial imaging of the stripe fluorescence to obtain magnetic field information of the sample to be measured, and then obtain an initial magnetic image of the sample to be measured; and a data processing component is set to perform Fourier transform and inverse Fourier transform on the initial magnetic image to obtain a first magnetic image; the initial magnetic image includes a two-dimensional real-space image obtained by superimposing sub-two-dimensional real-space images obtained at multiple moments, and the first magnetic image includes multiple sub-two-dimensional real-space images corresponding to the multiple moments. The present disclosure realizes sub-millisecond to microsecond time-resolved measurement of high-frequency dynamic signals under the requirement of high spatial resolution through the mutual cooperation between various components in a wide-field dynamic magnetic imaging device.

[0088] According to some embodiments of the present disclosure, the wide-field dynamic magnetic imaging device includes a probe assembly, a microwave magnetic field assembly, a laser modulation assembly, a stripe light modulation assembly, a fluorescence detection assembly, and a data processing assembly. The probe assembly includes a diamond containing an NV color center; the microwave magnetic field assembly is suitable for generating a uniform microwave field and a uniform bias magnetic field near the diamond to regulate the spin energy level and quantum state evolution process of the diamond; the laser modulation assembly is suitable for outputting an initial uniform pulse laser to excite the diamond to emit fluorescence, and the fluorescence includes magnetic field information of the sample to be tested; the stripe light modulation assembly is suitable for modulating the initial uniform pulse laser to output a stripe pulse laser so that the fluorescence emitted by the diamond is stripe fluorescence; or the fluorescence emitted by the diamond is directly modulated into stripe fluorescence. The fluorescence detection assembly is suitable for performing spatial imaging of the stripe fluorescence to obtain magnetic field information of the sample to be tested, and then obtain an initial magnetic image of the sample to be tested; and the data processing assembly is suitable for performing Fourier transform and inverse Fourier transform on the initial magnetic image to obtain a first magnetic image.

[0089] According to some embodiments of the present disclosure, the initial magnetic image includes a two-dimensional real-space image obtained by superimposing sub-two-dimensional real-space images obtained at multiple moments, and the first magnetic image includes multiple sub-two-dimensional real-space images corresponding to the multiple moments.

[0090] According to some embodiments of the present disclosure, a microwave magnetic field component is provided to generate a uniform microwave field and a uniform bias magnetic field near a diamond containing NV color centers contained in a probe component to regulate the spin energy level and quantum state evolution process of the diamond; a laser modulation component is provided to output an initial uniform pulsed laser to excite the diamond to emit fluorescence, and the fluorescence includes magnetic field information of the sample to be measured; a stripe light modulation component is provided to modulate the initial uniform pulsed laser to output a stripe pulsed laser so that the fluorescence emitted by the diamond is stripe fluorescence; or the stripe light modulation component modulates the fluorescence emitted by the diamond into stripe fluorescence; a fluorescence detection component is provided to perform spatial imaging of the stripe fluorescence to obtain magnetic field information of the sample to be measured, thereby obtaining an initial magnetic image of the sample to be measured; and a data processing component is provided to perform Fourier transform and inverse Fourier transform on the initial magnetic image to obtain a first magnetic image; the initial magnetic image includes a two-dimensional real-space image obtained by superimposing sub-two-dimensional real-space images obtained at multiple moments, and the first magnetic image includes multiple sub-two-dimensional real-space images corresponding to the multiple moments; and sub-millisecond to microsecond time-resolved measurement of high-frequency dynamic signals under high spatial resolution requirements is achieved.

[0091] According to some embodiments of the present disclosure, the temporal resolution is limited by the signal acquisition speed. Taking wide-field imaging as an example, the camera's shooting speed determines the time interval between two adjacent frames of the picture, so the highest temporal resolution of the imaging is the camera frame rate. In order to obtain dynamic images with high temporal resolution, the number of pixels for collecting light signals can be reduced, thereby reducing the readout time, but this will reduce the imaging field of view, resulting in a reduction in the flux of wide-field imaging, which is not conducive to the imaging requirements of a large field of view. In order to retain the advantage that the flux of wide-field imaging is much greater than that of scanning imaging, while improving the temporal resolution of imaging, non-uniform illumination can be used to encode images of different time periods at different positions in the k-space, and then the dynamic image information can be reconstructed through Fourier transform and spatial filtering.

[0092] The core component of widefield imaging is a microscope system. As a linear translation-invariant system, the imaging process can be described by the point spread function, which can be expressed as formula (1): (1);

[0093] in, represents the light field intensity distribution on the image plane, which represents the fluorescence distribution image of the sample obtained by the microscope system. Indicates the light field intensity distribution of the sample surface emission light. For NV-based wide-field magnetic imaging, the fluorescence is emitted by the NV color center, so the fluorescence intensity It is related to the spatial distribution of NV color centers. represents the point spread function of the microscope system, Represents the convolution operation.

[0094] Under uniform illumination conditions, the light field intensity of the sample emitted light is The spatial variation of is only related to the spatial distribution of NV color centers and the population of quantum states. In the context of magnetic imaging applications, the population is related to the external magnetic field B(t). Here, the two factors are combined and recorded as , assuming that the excitation light illumination intensity is I0 and the fluorescence collection efficiency of the microscope system for NV is α, the light field intensity of the sample emission light can be expressed as formula (2):

[0095] (2);

[0096] In this case, due to the slow camera readout, the fluorescence distribution caused by the dynamic magnetic signals at different moments is accumulated in one picture (i.e., the initial magnetic image), resulting in low temporal resolution.

[0097] If non-uniform excitation light is used to illuminate the NV color center, the fluorescence light field emitted by the sample and NV color center distribution It is linearly related to the intensity distribution of the illumination light field, and the linear relationship satisfies formula (3): (3);

[0098] Substituting formula (3) into formula (1) and performing Fourier transform, we can obtain formula (4): (4);

[0099] in, represents the optical transfer function of the microscope system, which is the Fourier transform of the point spread function , It represents that the microscope system limits the amount of information that passes through the microscope system, allowing only low-frequency information to pass through the system, and high-frequency information is cut off.

[0100] Now, using the cosine form of excitation light to illuminate the NV color center, the excitation light field intensity can be expressed as formula (5): (5);

[0101] in, and denote the average intensity and initial phase of the cosine illumination fringes, Indicates the magnitude and direction of the spatial frequency of the cosine fringe, and its modulus is the inverse of the fringe period. Through Fourier transform, the expression of cosine fringe in the frequency domain can be obtained as formula (6):

[0102] (6).

[0103] From this we can see that is the delta function at three positions in the frequency domain. Substituting formula (6) into formula (4), we can obtain the spectrum information of the image plane fluorescence image. The spectrum information of the image plane fluorescence image satisfies formula (7):

[0104] (7).

[0105] Formulas (6) and (7) show that the role of the cosine fringe illumination light is to copy the spectrum of the fluorescence image into three in the frequency domain, which is expressed as formulas (8), (9) and (10):

[0106] (8);

[0107] (9);

[0108] (10);

[0109] The zero-frequency position of one of them is located at the origin of the frequency domain, and the zero-frequency positions of the other two are moved to and The frequency domain signal at each position contains the complete spectrum information of the fluorescence image.

[0110] As can be seen from formula (7), cosine fringe illumination can move the image spectrum information to a specified position in k-space (i.e., frequency domain). Therefore, by adjusting the size and direction of the fringe spatial frequency, the image information at different times can be encoded to different positions in k-space, thereby achieving time-resolved imaging of dynamic images.

[0111] By using a digital micromirror device (DMD) 401 to generate an adjustable grating to modulate the stripe illumination light and achieving rapid switching of the stripes through electrical pulses, image information at a specified moment can be acquired at a speed far higher than the camera frame rate, thereby achieving high-time-resolution dynamic magnetic imaging and breaking through the limitation of the camera readout speed on the time resolution of the quantum diamond microscope.

[0112] Figure 1 The following schematically illustrates an experimental sequence diagram of high-speed signal acquisition achieved by Fourier k-space encoding in a wide-field dynamic magnetic imaging device according to an embodiment of the present disclosure.

[0113] According to some embodiments of the present disclosure, in order to obtain dynamic magnetic images with high temporal resolution, fluorescence measurement uses an electron-coupled device or a complementary metal oxide semiconductor camera used in a general quantum diamond microscope as a fluorescence detector. Figure 1 The stripe pattern in the middle is a schematic diagram of the two-dimensional grating pattern loaded by the digital micromirror device. The switching of the stripe pattern is controlled by the trigger signal. The microwave pulse is represented by the shaded square, and π / 2 represents the microwave pulse length. Figure 1 As shown, during the exposure of a camera frame, m fringe images are switched, and all NV color center fluorescence counts generated during the exposure period are collected into one image. This image can be expressed by formula (11): (11);

[0114] in It represents the mth cosine stripe illumination light played in time sequence, Indicates different moments ( ) The spatial distribution and quantum state population of the NV color center, which records the spatial magnetic field information recorded by the NV color center at different times. The frequency domain signal obtained by Fourier transforming formula (11) is expressed as formula (12):

[0115] (12)

[0116] Formula (11) and Formula (12) indicate that magnetic field images acquired at different times can be superimposed on the same image. Although magnetic field images at different times cannot be distinguished in real space, the image spectrum information at different times in k-space is separable, so images at different times can be distinguished in the frequency domain.

[0117] According to some embodiments of the present disclosure, Figure 1 The magnetic imaging pulse sequence in [1] lists three different magnetic field measurement pulse sequences: the Ramsey sequence, the Rabi oscillation, and the continuous wave spectrum sequence. Different sequences can be selected to match the measurement of different signals during the signal measurement process. Generally speaking, the quantum state of the NV color center is initialized using lasers and microwaves. The measured magnetic field causes the quantum state of the NV color center to evolve to a final state. The quantum state population is then read out using a laser to obtain magnetic field information. Different magnetic fields result in different NV color center populations, which in turn cause different NV color center fluorescence intensities. Widefield imaging can be used to obtain the magnitude of the magnetic field at different locations, while rapid fluorescence signal readout can reveal how the magnetic field changes over time.

[0118] The following uses these three sequences as examples to illustrate the principles of magnetic field measurement.

[0119] Ramsey sequence: laser initialization pulse - π / 2 microwave pulse - free evolution - π / 2 microwave pulse - laser readout pulse. First, the laser pulse initializes the NV color center to state, and then the π / 2 microwave pulse flips the NV to state, and then the NV evolves freely under the external magnetic field B(t), and the accumulated phase ,in is the gyromagnetic ratio of the NV color center, for The magnitude of the external magnetic field at that moment, is the free evolution time. After the free evolution is completed, the NV color center is prepared to state, and then a π / 2 microwave pulse flips the NV to Finally, the NV color center is read out using a laser pulse. Population density .

[0120] Rabi oscillation sequence: laser initialization pulse - variable length microwave pulse - laser readout pulse. This method can measure the spatial distribution of high frequency electromagnetic field intensity in the order of hundreds of MHz to GHz. The measured field is then applied to drive the energy level resonance of the NV center. The NV center fluorescence will change with the duration of the driving field application, and the frequency of the Rabi oscillation will ,in The field is linearly related to the microwave magnetic field .

[0121] Continuous wave spectrum sequence: Continuous laser and continuous microwave are applied simultaneously. According to the Zeeman effect, the external magnetic field causes the NV energy level to split. The energy level interval is Therefore, by measuring the resonance spectrum and determining the energy level of the NV color center, the magnetic field along the NV axis can be obtained. .

[0122] According to the embodiment of the present disclosure, according to formula (12), the frequency domain signals of the magnetic image at different times are encoded in different regions of the k-space. Therefore, spatial filtering in the frequency domain can be combined to perform image reconstruction. The inverse solution process includes steps 1 to 4.

[0123] In step 1, two-dimensional real space image acquisition is carried out as follows Figure 1 The fluorescence image is collected according to the experimental sequence shown in , and finally a cumulative fluorescence image encoded by multiple cosine fringes is obtained, which is the initial magnetic image.

[0124] In step 2, the initial magnetic image is Fourier transformed to obtain a frequency domain signal and a two-dimensional k-space image. The theoretical expression of step 2 is formula (12).

[0125] In step 3, the image frequency domain signals at different moments in the two-dimensional k-space image are separated, and a k-space filter is constructed for each moment of the image, whose center position is , with a width of W, which satisfies , that is, the filter width is less than or equal to the spatial frequency difference between the two fringes with the closest period and direction, to ensure that the separated signal will not be interfered by fringes in other directions; after applying the k-space filter to all cosine fringes, M two-dimensional k-space frequency domain signals are obtained, representing the frequency domain signals at different times.

[0126] In step 4, the zero frequency position of the two-dimensional frequency domain signal corresponding to each stripe is changed from Move to the origin of the two-dimensional k-space, and then perform inverse Fourier transform to obtain the real-space image encoded by each fringe, that is, the two-dimensional real-space magnetic field map at the corresponding moment, that is, the first magnetic image including multiple sub-two-dimensional real-space images corresponding to multiple moments.

[0127] Figure 2 The figure schematically shows the working principle of the probe assembly in the wide-field dynamic magnetic imaging device according to an embodiment of the present disclosure.

[0128] According to some embodiments of the present disclosure, Figure 2 As shown, the probe assembly 1 further includes a uniform radiation structure 102 , which is adapted to provide a microwave field to change the spin quantum state of the NV color center in the diamond 101 .

[0129] According to some embodiments of the present disclosure, a microwave field is provided by providing a uniform radiation structure 102 to change the spin quantum state of the NV color center in the diamond 101 .

[0130] According to some embodiments of the present disclosure, the uniform microwave field generated by the uniform radiation structure 102 has a range of the order of 100 microns, and the uniformity of the microwave field can reach more than 95%, thereby ensuring that all NV color centers are affected in the same way, thereby improving the accuracy of manipulating the spin quantum state of the NV color center in the diamond 101.

[0131] According to some embodiments of the present disclosure, Figure 2 As shown, the substrate 8 is arranged below the sample to be tested 7, and the substrate 8 is suitable for supporting the sample to be tested 7.

[0132] Figure 3 The figure schematically shows the relative positions of the diamond containing NV color centers and the uniform radiation structure in the probe assembly of the wide-field dynamic magnetic imaging device according to an embodiment of the present disclosure.

[0133] According to some embodiments of the present disclosure, Figure 3 As shown, the diamond containing NV color center is arranged at a central symmetrical position of the uniform radiation structure.

[0134] According to some optional embodiments of the present disclosure, the uniform radiation structure 102 is a waveguide, and the shape of the waveguide can be set to achieve uniform distribution of the microwave field in the diamond region containing NV color centers.

[0135] According to some embodiments of the present disclosure, the surface of the diamond 101 containing NV color centers is flat and contains multiple NV color centers, which form a thin layer inside the diamond 101; the depth difference between two adjacent NV color centers is less than 10 microns, and the distance between two adjacent NV color centers in the horizontal direction is less than the optical diffraction limit.

[0136] According to some embodiments of the present disclosure, the surface of diamond 101 containing NV centers is smooth, which can improve the accuracy of external magnetic field sensing. Furthermore, diamond 101 containing NV centers has no surface structure, that is, diamond 101 has fewer internal defects and impurities, reducing interference with the quantum state. Marking specific locations on diamond 101 (such as the location of the NV center center) can improve the accuracy of identifying the sensing area and facilitate the initialization, manipulation, and reading of the quantum state of the NV center.

[0137] According to some embodiments of the present disclosure, by setting the depth difference between two adjacent NV centers to be less than 10 microns, the distance between two adjacent NV centers in the horizontal direction is less than the optical diffraction limit, and making all NV centers in the diamond 101 satisfy this arrangement, the uniformity and consistency of quantum sensing are improved. When the depth difference between all NV centers is less than 10 microns, all NV centers are affected by the diamond lattice in a similar way, further enhancing the uniformity of sensing. When the horizontal spacing of all NV centers is less than the optical diffraction limit of the system, a smaller light spot can be used to excite multiple NV centers individually or simultaneously, thereby improving the resolution and sensitivity of optical measurement. The fact that all NV centers satisfy this arrangement also improves the control efficiency of the microwave field, allowing the microwave field to act more evenly on all NV centers.

[0138] According to some embodiments of the present disclosure, when multiple NV color centers are formed inside the diamond 101 with a certain density and arrangement, they can form a two-dimensional thin layer. The thin layer may be located near the surface of the diamond 101, or it may be at a certain depth inside the diamond 101. Due to the optical and quantum properties of the NV color center itself, the thin layer composed of NV color centers also exhibits similar properties. For example, the thin layer may exhibit strong fluorescence under laser pumping, and its fluorescence properties can be regulated by controlling factors such as temperature. Since the spin state of the NV color center can be manipulated and detected by lasers and microwaves, the thin layer can be used as a two-dimensional quantum bit array to implement various quantum information processing tasks.

[0139] Figure 4 The block diagram schematically shows a microwave magnetic field component in a wide-field dynamic magnetic imaging device according to an embodiment of the present disclosure.

[0140] According to some embodiments of the present disclosure, Figure 4 As shown, the microwave magnetic field assembly 2 includes: a microwave source 201, a microwave beam splitter 202, a microwave switch 203, a microwave combiner 204, a microwave amplifier 205, an isolator 206, an impedance matching device 207, and a magnetic field source 208. The microwave source 201 is adapted to generate an initial microwave of a specific frequency and power; the microwave beam splitter 202 is adapted to split the initial microwave into two first microwaves of equal power and a 90° phase difference; the microwave switch 203 is adapted to control the on / off transmission paths of the two first microwaves; the microwave combiner 204 is adapted to combine the two first microwaves into a second microwave; the microwave amplifier 205 is adapted to amplify the power of the second microwave to generate a third microwave, which then enters the uniform radiation structure 102; the isolator 206 is adapted to prevent the third microwave from being reflected and entering the microwave amplifier 205; the impedance matching device 207 is adapted to reduce the loss during the transmission of the third microwave; and the magnetic field source 208 is adapted to provide a uniform bias magnetic field.

[0141] According to some embodiments of the present disclosure, a microwave magnetic field assembly 2 is provided to regulate the generated microwave field and bias magnetic field to ensure a uniform microwave field and bias magnetic field environment near the diamond 101. Based on the frequency and power requirements of the target uniform microwave field, a suitable microwave source 201 is selected that can generate the target uniform microwave field frequency and power. The initial microwaves of a specific frequency and power include the frequency and power of the target uniform microwave field, and the frequency range of the initial microwaves is typically between 300 MHz and 300 GHz.

[0142] According to some embodiments of the present disclosure, the uniform microwave field is within the diamond NV color center region; and the direction of the bias magnetic field is along the direction of the NV color center axis.

[0143] According to some embodiments of the present disclosure, Figure 4 As shown, microwave switch 203 includes a first microwave switch 2031 and a second microwave switch 2032. Microwave switch 203 controls the transmission paths of the two first microwaves, enabling flexible control of microwave signal transmission. Microwave amplifier 205 amplifies the power of the second microwave to generate a third microwave, ensuring that the third microwave's power, upon entering uniform radiation structure 102, produces a power that meets the target uniform microwave field. Isolator 206 prevents the third microwave from reflecting and entering the microwave amplifier, thereby protecting microwave amplifier 205 from damage. Impedance matching 207 minimizes impedance variations encountered by the microwave signal during transmission, reducing transmission losses during the third microwave. Impedance matching 207 is located at the end of the entire microwave magnetic field assembly 2 to protect the microwave circuit.

[0144] According to some embodiments of the present disclosure, impedance matching 207 refers to the characteristic impedance of the connected transmission line being equal in magnitude and in phase with the internal resistance of the microwave source 201, or the characteristic impedance of the transmission line being equal in magnitude and in phase with the connected load impedance (i.e., a uniform radiation structure), so as to ensure maximum power transmission of the microwave signal and reduce reflection loss of the microwave signal.

[0145] According to some embodiments of the present disclosure, microwave source 201 comprises any one of a semiconductor device and a resonant cavity; magnetic field source 208 comprises any one of a coil and a large permanent magnet. Microwave source 201 generates a spatially uniform microwave field near diamond 101; magnetic field source 208 generates a spatially uniform bias magnetic field near diamond 101. The bias magnetic field has a uniformity range of on the order of 1 mm, and the uniformity of the uniform bias magnetic field can reach over 95%. The uniform microwave field generated by uniform radiating structure 102 has a range of on the order of 100 microns, and the uniformity of the microwave field can reach over 95%, with a uniformity of approximately 99.5% within a range of 500 microns.

[0146] Figure 5The figure schematically shows a block diagram of a laser modulation component in a wide-field dynamic magnetic imaging device according to an embodiment of the present disclosure.

[0147] According to some embodiments of the present disclosure, Figure 5 As shown, the laser modulation assembly 3 includes: a laser 301, a first half-wave plate 302, an acousto-optic modulator group 303, a lens group 304, and a beam shaper 305. The laser 301 is adapted to output an initial continuous laser beam; the first half-wave plate 302 is adapted to control the polarization direction of the initial continuous laser beam to obtain a first continuous laser beam; the acousto-optic modulator group 303 is adapted to modulate the first continuous laser beam to obtain an initial pulsed laser beam, thereby improving the on / off ratio of the initial pulsed laser beam; the lens group 304 is adapted to adjust the beam diameter of the initial pulsed laser beam; and the beam shaper 305 is adapted to convert the initial pulsed laser beam into a flat-top beam with uniform intensity distribution, thereby outputting an initial uniform pulsed laser beam.

[0148] According to some embodiments of the present disclosure, the initial continuous laser is a linearly polarized Gaussian beam with a Gaussian intensity distribution and a linearly polarized polarization state. The laser power of the initial continuous laser is in the order of 1 to 5 W. The acousto-optic modulator (Acousto-Optic The AOM (Acousto-Optic Modulator) group is a cascaded configuration of multiple acousto-optic modulators (AOMs). The AOM group modulates the first continuous laser light using an external modulation signal, controlling the on / off state of the first continuous laser light transmission path, thereby generating an initial pulsed laser light. The lens group 304 includes a first convex lens 3041 and a second convex lens 3042. The back focal plane of the first convex lens 3041 coincides with the front focal plane of the second convex lens 3042, forming a confocal relationship. This allows the incident near-parallel laser beam to be adjusted in diameter by the lens group 304 and then emitted in the same near-parallel state. The exiting beam diameter is equal to the incident beam diameter multiplied by the ratio of the focal lengths of the second convex lens 3042 to the first convex lens 3041. The beam diameter can be adjusted by selecting an appropriate focal length. The beam shaper 305 is a diffractive optical element, such as a flat-top beam shaper, which converts the initial pulsed laser light into an initial uniform pulsed laser light. The intensity of the initial uniform pulsed laser light is uniformly distributed.

[0149] According to some optional embodiments of the present disclosure, the laser 301 generates an initial continuous laser with a power of 1 watt and a wavelength of 532 nanometers; the acousto-optic modulator group is a cascade configuration of three acousto-optic modulators, which can make the overall switching ratio as high as 10 7 : 1. The efficiency of converting the first continuous laser into the initial pulse laser is improved, and the loss of the first continuous laser signal is reduced; the uniformity of the initial uniform pulse laser is about 90%.

[0150] Figure 6The block diagram schematically shows a stripe light modulation component in a wide-field dynamic magnetic imaging device according to an embodiment of the present disclosure.

[0151] According to some embodiments of the present disclosure, Figure 6 As shown, the stripe light modulation assembly 4 includes: a digital micromirror device 401, 4f optical systems 402 and 404, and a filter 403. The digital micromirror device 401 is adapted to diffract an initial uniform pulsed laser into multiple beams of parallel light propagating in different directions; the 4f optical systems 402 and 404 are adapted to convert the multiple beams of parallel light into stripe light, which exhibits a two-dimensional distribution of alternating bright and dark stripes on the output plane; and the filter 403 is disposed within the 4f optical systems 402 and 404 to filter out stray light from the multiple beams of parallel light.

[0152] According to some embodiments of the present disclosure, a digital micromirror device (DMD) is a micro-mirror array, each of which can be independently tilted to two different angles (e.g., +12° and -12°), thereby reflecting light in two different directions. When parallel light is incident on the DMD, a binary grating can be formed by controlling the tilt angle of each micromirror. This binary grating is like a two-dimensional black and white chessboard, where the white part indicates that light can pass through and the black part indicates that light is blocked. Therefore, the DMD has two states: "on" and "off". When the DMD micromirrors are in the "on" state, light is allowed to pass through. When the DMD micromirrors are in the "off" state, light is blocked.

[0153] According to some embodiments of the present disclosure, the 4f optical system 402, 404 includes two lens assemblies, a first lens 402 and a second lens 404. The focal lengths of the first lens 402 and the second lens 404 are equal, both f, and the distance between the first lens 402 and the second lens 404 is 2f. The digital micromirror device 401 is located at the front focal plane of the first lens 402, and the filter 403 is located at the back focal plane of the first lens 402. The first lens 402 performs a Fourier transform on multiple beams of parallel light propagating in different directions, forming a spectrum plane containing spatial spectrum information at the back focal plane of the first lens 402. The filter 403 filters out stray light and multi-order diffracted light from the multiple beams of parallel light. The second lens 404 images the resulting striped light onto an output plane, where the striped light presents a two-dimensional distribution of alternating bright and dark stripes.

[0154] According to some embodiments of the present disclosure, when parallel light passes through first lens 402, it forms a Fourier transform spectrum of the light field at the back focal plane of first lens 402 (i.e., at a distance f from first lens 402). This transform contains the spatial frequency information of the light field. Filter 403 modifies the Fourier transform spectrum, thereby changing the spatial distribution of the light field. Second lens 404 converts the filtered Fourier transform spectrum back into a light field, thereby producing the desired two-dimensional stripe light distribution on the output plane. The shape, direction, and contrast of these stripes can be controlled by adjusting the DMD pattern and the design of filter 403.

[0155] According to some embodiments of the present disclosure, the stripe light modulation component 4 can modulate uniform light into stripe structured light with a stripe contrast greater than 50%. The stripe light modulation component 4 can also achieve rapid switching between different stripes, with a switching rate of up to 50 kHz, thereby providing dynamic wide-field magnetic imaging with a temporal resolution of 20 microseconds. The stripe light modulation component 4 can be placed after the excitation modulation component 3 to modulate the stripe excitation light, or before the fluorescence detection component 5 to achieve stripe modulation of fluorescence.

[0156] Figure 7 The schematic diagram shows the principle of modulating stripe light by a stripe light modulation component in a wide-field dynamic magnetic imaging device according to an embodiment of the present disclosure.

[0157] According to some embodiments of the present disclosure, Figure 7 As shown, parallel light is incident on a digital micromirror device, which generates a binary grating through the digital micromirror device 401, diffracting the incident light into multiple beams of parallel light propagating in different directions. The light is then Fourier-space filtered through the 4f optical system 402, 404 and the filter 403 to generate a two-dimensional stripe light distribution on the output plane.

[0158] According to some embodiments of the present disclosure, assuming that the direction of light propagation is always in the z-direction, the light field distribution of parallel incident light can be described as a uniformly distributed light field E0 in the xy plane. A DMD is placed in the front focal plane of the first lens 402 and loaded with a grating pattern. The micro-mirrors in the open state reflect the incident light into the subsequent optical path. Simultaneously, the loaded grating pattern causes the incident light to diffract, causing the light exiting the DMD to propagate in multiple directions.

[0159] The following uses the grating in the y direction as an example to illustrate the process of generating stripes. Define a coordinate system x'Oy' on the grating optical surface, assuming that the period of the loaded grating in the y' direction is T y , the width of each slit is D, and the transmittance function of DMD can be described as formula (13):

[0160] (13)

[0161] in, The maximum number of grating periods that the DMD optical surface can accommodate. The specific value is related to the size and direction of the grating period. is the aperture function of the DMD light-passing surface, whose size is the product of the DMD resolution M×N and the pixel period Δd, The expression is formula (14): ,in, is a one-dimensional rectangular function.

[0162] Formula (13) indicates that the grating loaded by the DMD is a plurality of rectangular slits distributed along the y-direction. After the incident light hits the grating, the outgoing light will be diffracted to different positions in the y-direction. The light field obtained at the focal plane of the first lens 402 is the Fourier transform of the grating pattern, that is, the spatial spectrum information. This light field can be obtained by Fourier transforming formula (13). The transformation process can be expressed as formula (15):

[0163] (15);

[0164] in, is the light field distribution at the focal plane of the first lens 402; is the Fourier transform of the DMD clear aperture; It can be expressed as formula (16):

[0165] (16).

[0166] In order to generate streak light, a filter 403 is placed on the rear focal plane of the first lens 402 to remove the high diffraction orders and retain the ±1 order and 0 order to enter the subsequent optical path. The light field distribution after filtering can be expressed as formula (17):

[0167] (17), in, is the light field distribution after filtering.

[0168] The light field distribution formed at the rear focal plane (i.e., output plane) of the second lens 404 is is the Fourier transform of formula (17), It can be expressed as formula (18):

[0169] (18), in, for, It can be expressed as formula (19):

[0170] (19).

[0171] According to formula (18), the distribution of light intensity at the focal plane behind the second lens 404 can be obtained as , It can be expressed as formula (20):

[0172] (20).

[0173] According to some embodiments of the present disclosure, since the DMD is a planar array composed of multiple micromirrors, when receiving parallel light, the micromirror array acts like a two-dimensional grating, causing interference and diffraction of the outgoing light. Therefore, the outgoing light contains not only the target stripe light described above, but also multi-order diffracted light caused by the periodic structure of the pixel elements. To ensure that the target stripe light is not interfered with, it is necessary to filter out other multi-order diffracted light. The following first describes the formation principle of multi-order diffracted light and then describes the filtering method for multi-order diffracted light.

[0174] Assuming that the side length of the DMD pixel is d and the pixel period is Δd, the transmittance function of the DMD can be expressed as formula (21):

[0175] (twenty one), in, is the aperture function of the DMD light-transmitting surface, and its expression is given by formula (14); It is a two-dimensional rectangular function, which means that the shape of a single pixel is a d×d square, and the center position is a plane coordinate system. The convolution operation represents the distribution of pixels at different positions on the DMD optical surface. represents the position distribution function of the DMD pixel array, It can be expressed as formula (22):

[0176] (twenty two).

[0177] After passing through the first lens 402, the image obtained at the rear focal plane of the first lens 402 is the Fourier transform of the DMD optical surface pattern. The complex amplitude of the light field at the focal plane is expressed as formula (23):

[0178] (twenty three), in, and They can be expressed as formulas (24) and (25) respectively:

[0179] (twenty four),

[0180] (25).

[0181] Formula (24) is processed according to the Fourier transform of the rectangular function. The Fourier transform of the rectangular function can be expressed as formula (26):

[0182] (26).

[0183] Formula (24) is processed according to the Fourier transform formula (26) of the rectangular function to obtain formula (27):

[0184] (27).

[0185] Using the Fourier transform of the Dirac comb function, that is, formula (28):

[0186] (28).

[0187] According to the Fourier transform of the Dirac comb function (28), we can obtain formula (29):

[0188] (29).

[0189] Therefore, formula (29) indicates that multi-order diffraction light caused by the DMD pixel structure is obtained on the back focal plane of the first lens 402, and the intensity of each order of diffraction light is modulated by the single slit diffraction caused by the micro-mirror element.

[0190] In order to obtain the target stripe light, the redundant diffraction orders should be removed and only the zero diffraction order with the largest intensity should be retained. Therefore, a low-pass filter, namely filter 403, can be placed on the rear focal plane of the first lens 402 to filter out the high diffraction orders. At the same time, in order to ensure that the ±1 order of the target stripe light is not filtered out, the width of the low-pass filter is W. f Needs to be satisfied .

[0191] Figure 8 The block diagram schematically shows a fluorescence detection component in a wide-field dynamic magnetic imaging device according to an embodiment of the present disclosure.

[0192] According to some embodiments of the present disclosure, Figure 8 As shown, the fluorescence detection assembly 5 includes an imaging lens 501, a multi-stage filter 502, and a fluorescence detector 503. The imaging lens 501 is adapted to focus fluorescence to form a fluorescence image; the multi-stage filter 502 is adapted to filter out stray light signals and laser light reflected from the surface of the diamond 101; and the fluorescence detector 503 is adapted to convert the fluorescence signal into an electrical signal to obtain magnetic field information of the sample 7 to be tested.

[0193] According to some embodiments of the present disclosure, the imaging lens 501 in the fluorescence detection assembly 5 is used to focus the fluorescence emitted by the diamond 101 to form a fluorescence image; the multi-stage filter 502 is used to filter out stray light signals and laser reflected from the surface of the diamond 101; and the fluorescence detector 503 is used to convert the fluorescence signal into an electrical signal, so as to obtain the magnetic field information of the sample to be tested 7.

[0194] According to some embodiments of the present disclosure, the fluorescence detector 503 can distinguish the spatial position of the NV color center based on the fluorescence signal.

[0195] According to some optional embodiments of the present disclosure, the fluorescence detector 503 includes any one of an electron coupled device and a complementary metal oxide semiconductor, and the multi-stage filter 502 includes three 900-nanometer short-pass filters.

[0196] Figure 9 The diagram schematically shows the optical path for generating and collecting stripe fluorescence in a wide-field dynamic magnetic imaging device according to an embodiment of the present disclosure.

[0197] According to some embodiments of the present disclosure, Figure 9 As shown, a laser 301 generates an initial continuous laser beam. A first half-wave plate 302 adjusts the polarization direction of the initial continuous laser beam to obtain a first continuous laser beam. The first continuous laser beam is modulated by an acousto-optic modulator group 303 to output an initial pulsed laser beam. A lens group 304 adjusts the beam diameter of the initial pulsed laser beam. The initial pulsed laser beam with adjusted beam diameter is converted by a beam shaper 305 into an initial uniform pulsed laser beam with uniform light intensity distribution. A second half-wave plate 306 adjusts the polarization direction of the initial uniform pulsed laser beam. The initial uniform pulsed laser beam with changed polarization direction is reflected by a first reflective component 307 to a digital micromirror device 401. The digital micromirror device 401 diffracts the initial uniform pulsed laser beam into multiple beams of parallel light propagating in different directions. When the micromirrors of the DMD are in the "on" state, the parallel light beams are introduced into the 4f optical systems 402 and 404. The parallel light beams are converted into striped light by the 4f optical systems 402 and 404 and the filter 403, and present a two-dimensional distribution of alternating bright and dark stripes on the output plane. The filter 403 filters out the high-order diffraction light, and the remaining 0th-order and ±1st-order light passes through the second lens 404, the first focusing lens 11, and the third reflector 12 in sequence, and then is reflected by the dichroic mirror 13 into the lens of the objective lens 10, and finally forms stripe light illumination on the plane where the NV color center thin layer of the diamond 101 is located. The final stripe excitation light illumination range is greater than 200 microns, and the stripe contrast is greater than 40%.

[0198] According to some embodiments of the present disclosure, the stripe light is a stripe pulse laser, and the NV color center in the diamond 101 absorbs the stripe light and emits stripe fluorescence. The stripe fluorescence is collected by the objective lens 10, transmitted through the dichroic mirror 13 into the imaging lens 501, and then passes through the multi-stage filter 502, and finally is collected on the target surface of the fluorescence detector 503.

[0199] According to some optional embodiments of the present disclosure, first lens 402 is a Fourier lens; dichroic mirror 13 is a 600 nm long-pass dichroic mirror; multi-stage filter 502 is a 900 nm short-pass filter; first reflective assembly 307 includes two reflective mirrors, first reflective mirror 3071 and second reflective mirror 3072, or first reflective assembly 307 includes a single reflective mirror; and filter 403 is a low-pass filter.

[0200] Figure 10 The figure schematically shows the optical path diagram for generating and collecting stripe fluorescence in a wide-field dynamic magnetic imaging device according to another embodiment of the present disclosure.

[0201] According to some embodiments of the present disclosure, Figure 10 As shown, laser 301 generates an initial continuous laser beam. A first half-wave plate 302 adjusts the polarization direction of the initial continuous laser beam to obtain a first continuous laser beam. The first continuous laser beam is modulated by an acousto-optic modulator group 303 to output an initial pulse laser beam. A lens group 304 adjusts the beam diameter of the initial pulse laser beam. The initial pulse laser beam with adjusted beam diameter is converted into an initial uniform pulse laser beam with uniform light intensity distribution by a beam shaper 305. A second half-wave plate 306 adjusts the polarization direction of the initial uniform pulse laser beam. The polarization-changed initial uniform pulse laser beam is sequentially reflected by a first reflective assembly 307 and then focused by a first focusing lens 11 to output a focused pulse laser beam. The focused pulse laser beam is reflected by a dichroic mirror 13 and enters the objective lens 10 lens. It is focused on the pupil plane of the objective lens 10 lens, then passes through the objective lens and is emitted as parallel light, finally forming uniform excitation light illumination on the plane where the 12 diamond NV color center thin layer is located. The resulting uniform excitation light illumination range is greater than 200 microns, and the uniformity within the 200 micron range is greater than 90%.

[0202] According to some embodiments of the present disclosure, the NV color center in the diamond 101 absorbs uniform excitation light to generate fluorescence. The emitted fluorescence is collected by the objective lens 10, passes through the dichroic mirror 13, enters the achromatic lens 14, and then passes through the third reflector 12 to adjust the direction of the light and then enter the digital micromirror device 401 at a suitable angle. The digital micromirror device 401 is in the focal plane of the first lens 402, and a pattern is loaded to perform structured light modulation on the wide-field fluorescence distribution of the NV color center. The micromirror of the DMD in the "on" state introduces the outgoing light into the first lens 402, and a filter 403 is placed on the focal plane of the first lens 402 to filter out the high-order diffraction light. The remaining 0th order and ±1st order light passes through the second lens 404 to output stripe fluorescence. The stripe fluorescence passes through the imaging lens 501 and the multi-stage filter 502, and is finally collected on the target surface of the fluorescence detector 503.

[0203] According to some embodiments of the present disclosure, the objective lens 10 and the imaging lens 501 are combined to form a conjugate plane between the NV color center thin layer plane of the diamond 101 and the fluorescence detection / 503 target surface, and the counts accumulated by each fluorescence detection unit on the target surface of the fluorescence detector 503 are converted into a planar distribution of NV color center fluorescence.

[0204] According to some optional embodiments of the present disclosure, the first lens 402 is an achromatic Fourier lens; the imaging lens 501 is an achromatic imaging lens; the dichroic mirror 13 is a 600-nanometer long-wave pass dichroic mirror; the multi-stage filter 502 is a 900-nanometer short-pass filter; and the first reflective assembly 307 includes a reflector.

[0205] According to some embodiments of the present disclosure, a Fourier lens can transform an incident light wave into a linear combination of monochromatic plane waves of different frequencies, a process corresponding to the Fourier transform in mathematics; an achromatic Fourier lens has the ability to eliminate or reduce chromatic aberration while maintaining the basic functions of a Fourier lens; an achromatic imaging lens is an optical element specifically used for imaging, and its main function is to improve imaging quality by eliminating or reducing chromatic aberration.

[0206] According to some embodiments of the present disclosure, by setting the first lens 402 as an achromatic Fourier lens and the imaging lens 501 as an achromatic imaging lens, the chromatic aberration of the collected stripe fluorescence is reduced and the imaging quality of the stripe fluorescence is improved.

[0207] Figure 11 The figure schematically shows the working principle of the temperature control component in the wide-field dynamic magnetic imaging device according to an embodiment of the present disclosure.

[0208] According to some embodiments of the present disclosure, Figure 11As shown, the wide-field dynamic magnetic imaging apparatus further includes a temperature control assembly 9, comprising a temperature monitor 901, a temperature control box 902, and a temperature controller 903. The temperature monitor 901 is adapted to monitor the surface temperature of the diamond 101; the temperature control box 902 is adapted to house the probe assembly 1; and the temperature controller 903 is adapted to control the temperature inside the temperature control box 902 to stabilize at a target temperature.

[0209] According to some embodiments of the present disclosure, a temperature control assembly 9 is provided to control the temperature inside the temperature control box 902, thereby controlling the temperature of the surface of the diamond 101, so that the temperature of the surface of the diamond 101 is stabilized at a target temperature, ensuring the stability of the target temperature within ±0.01 degrees Celsius. By controlling the temperature of the surface of the diamond 101 to be stable at the target temperature, the temperature of the NV color center in the diamond 101 is also controlled to be stable at the target temperature. When the NV color center is in a stable temperature environment, this spin energy level structure can maintain its stability and a long spin coherence time, thereby improving the accuracy of quantum state optical initialization, readout, and quantum state manipulation.

[0210] According to some optional embodiments of the present disclosure, the target temperature is about 30°C.

[0211] Figure 12 The diagram schematically shows the position relationship between the position adjustment component, the probe component, and the sample to be measured in the wide-field dynamic magnetic imaging device according to an embodiment of the present disclosure.

[0212] According to some embodiments of the present disclosure, the wide-field dynamic magnetic imaging apparatus further includes a position adjustment assembly 15, which includes a Z-axis position adjustment device 151, a two-axis position adjustment device 152, and a three-axis position adjustment device 153. The Z-axis position adjustment device 151 is adapted to adjust the position of the objective lens 10; the two-axis position adjustment device 152 is adapted to adjust the position of the probe assembly 1; and the three-axis position adjustment device 153 is adapted to adjust the position of the sample 7 to be measured. The distance between the probe assembly 1 and the sample 7 to be measured is adjusted by adjusting the two-axis position adjustment device 152 and the three-axis position adjustment device 153.

[0213] According to some embodiments of the present disclosure, Figure 12As shown, the probe assembly 1 is mounted on a two-axis position adjustment device 152. The probe assembly 1 is located between the objective lens 10 and the sample 7 to be tested. The two-axis position adjustment device 152 can adjust the position of the probe assembly 1 in the X-axis direction and the Y-axis direction, that is, the position of the probe assembly 1 in the xy plane. The objective lens 10 is mounted on a Z-axis position adjustment device 151. The Z-axis position adjustment device 151 controls the objective lens 10 to focus on the NV color center plane, thereby realizing wide-field fluorescence imaging and readout of the NV color center. The sample 7 to be tested is mounted on a three-axis position adjustment device 153. The three-axis position adjustment device 153 can adjust the position of the sample 7 to be tested and the substrate 8 in the three directions of the X-axis, Y-axis and Z-axis.

[0214] According to some embodiments of the present disclosure, the three-axis position adjustment device 153 includes a three-axis large-range position adjustment device 1531 and a three-axis small-range position adjustment device 1532. The single-axis travel of the three-axis small-range position adjustment device 1532 is on the order of several hundred microns, with a resolution (adjustment accuracy) of 1 nanometer. The single-axis travel of the Z-axis position adjustment device 151, the two-axis position adjustment device 152, and the three-axis large-range position adjustment device 1531 is on the order of tens of millimeters, with a resolution (adjustment accuracy) of 10 microns. The adjustment accuracy of the three-axis small-range position adjustment device 1532 is greater than that of the three-axis large-range position adjustment device 1531. The three-axis large-range position adjustment device 1531 enables the sample 7 and substrate 8 to be moved over a large range. The three-axis small-range position adjustment device 1532 uses a nano-piezoelectric displacement stage for nanometer-level spatial positioning, improving the accuracy of spatial position adjustment of the sample 7 and substrate 8 to be tested.

[0215] According to some embodiments of the present disclosure, the process of experimental measurement of the wide-field dynamic magnetic imaging device is as follows: first, install the diamond 101 containing the NV color center and the sample 7 to be tested; then adjust the sample positions of the diamond 101 containing the NV color center and the sample 7 to be tested so that the NV color center plane moves to the focal plane of the objective lens 10; adjust the external magnetic field so that the direction of the magnetic field coincides with the direction of the NV axis; then perform coherence time measurement to find the NV color center whose properties meet the experimental requirements. After determining the test area, experimental data collection is performed. Before completing all experiments, each time the time-resolved k-space encoding data collection is completed, the NV color center position calibration is performed, and the experiment is continued after the calibration is completed. Repeat the above experimental process until the end of the experiment, and use the data processing component 6 to process the data.

[0216] According to some embodiments of the present disclosure, the data processing component 6 includes a computer workstation with a GPU computing unit. The image reconstruction process in the data processing includes: first, performing a Fourier transform on the real-space images superimposed at each time point, resolving the spectral information of the image acquired at each time point in k-space, moving each spectrum to the origin of k-space, then applying a filter 403 to sort the signals, and finally reconstructing the real-space images at each time point through an inverse Fourier transform to complete the image reconstruction.

[0217] According to some embodiments of the present disclosure, during specific experimental measurements performed by a wide-field dynamic magnetic imaging device, a computer-controlled square wave sequence generator serves as a clock source to synchronize the various components within the system. Upon initiation of the experiment, the square wave sequence generator emits square wave pulses, simultaneously controlling the following components within the system: the acousto-optic modulator group 303 within the laser modulation assembly 3 to switch the laser; the digital micromirror device 401 within the stripe light modulation assembly 4 to switch the stripe pattern in different directions; the fluorescence detector 503 within the fluorescence detection assembly 5 to collect fluorescence; and the microwave switch 203 within the microwave magnetic field assembly 2 to manipulate the output microwave field. The acousto-optic modulator group 303, the digital micromirror device 401, the fluorescence detector 503, and the microwave switch 203 are combined in a specific time sequence to collect the corresponding fluorescence signals, enabling high-resolution k-space encoding experimental data acquisition based on stripe light modulation.

[0218] According to some embodiments of the present disclosure, the magnetic field information is encoded in the NV color center quantum state by combining pulsed laser, microwave field, magnetic field and pulse sequence, and the quantum state fluorescence signal is read out by laser pulse.

[0219] Figure 13 The flowchart of the wide-field dynamic magnetic imaging method according to an embodiment of the present disclosure is schematically shown.

[0220] Another aspect of the present disclosure provides a wide-field dynamic magnetic imaging method, using the wide-field dynamic magnetic imaging device, such as Figure 13 As shown, the wide-field dynamic magnetic imaging method includes operations S101 to S105.

[0221] In operation S101 , the laser modulation assembly 3 is used to output an initial uniform pulse laser to excite the diamond 101 containing NV color centers to emit fluorescence, and the fluorescence includes magnetic field information of the sample 7 to be tested.

[0222] In operation S102 , the stripe light modulation component 4 is used to modulate the initial uniform pulse laser to output stripe pulse laser, so that the fluorescence emitted by the diamond 101 is stripe fluorescence; or the fluorescence emitted by the diamond 101 is modulated into stripe fluorescence.

[0223] In operation S103 , the microwave magnetic field assembly 2 is used to generate a uniform microwave field and a uniform bias magnetic field at the position of the diamond 101 to regulate the spin energy level and quantum state evolution process of the diamond 101 .

[0224] In operation S104 , the stripe fluorescence is spatially imaged by using the fluorescence detection component 5 to obtain magnetic field information of the sample to be tested 7 , thereby obtaining an initial magnetic image of the sample to be tested 7 .

[0225] In operation S105 , the data processing component 6 performs Fourier transform and inverse Fourier transform on the initial magnetic image to obtain a first magnetic image.

[0226] According to some embodiments of the present disclosure, the initial magnetic image includes a two-dimensional real-space image obtained by superimposing sub-two-dimensional real-space images obtained at multiple moments, and the first magnetic image includes multiple sub-two-dimensional real-space images corresponding to the multiple moments.

[0227] According to some embodiments of the present disclosure, a laser modulation component 3 is used to output an initial uniform pulse laser to excite the diamond 101 containing NV color centers to emit fluorescence, and the fluorescence includes magnetic field information of the sample to be tested 7; the stripe light modulation component 4 is used to modulate the initial uniform pulse laser to output a stripe pulse laser, so that the fluorescence emitted by the diamond 101 is stripe fluorescence; or the fluorescence emitted by the diamond 101 is modulated into stripe fluorescence; a microwave magnetic field component 2 is used to generate a uniform microwave field and a uniform bias magnetic field at the position of the diamond 101 to regulate the spin energy level and quantum state evolution process of the diamond 101; the fluorescence detection component 5 is used to perform spatial imaging of the stripe fluorescence to obtain magnetic field information of the sample to be tested 7, and then obtain an initial magnetic image of the sample to be tested 7; the initial magnetic image is Fourier transformed and inverse Fourier transformed using a data processing component 6 to obtain a first magnetic image; and sub-millisecond to microsecond time-resolved measurement of high-frequency dynamic signals under high spatial resolution requirements is achieved.

[0228] Figure 14 The flowchart schematically shows a method for wide-field dynamic magnetic imaging according to an embodiment of the present disclosure, which uses a data processing component to perform Fourier transform and inverse Fourier transform on an initial magnetic image to obtain a first magnetic image.

[0229] According to some embodiments of the present disclosure, Figure 14 As shown, the data processing component 6 performs Fourier transform and inverse Fourier transform on the initial magnetic image to obtain the first magnetic image, including operations S201 to S203.

[0230] In operation S201 , Fourier transform processing is performed on the initial magnetic image to obtain a frequency domain signal, which is represented in the form of a two-dimensional k-space image.

[0231] In operation S202 , image frequency domain signals at different moments are acquired according to the two-dimensional k-space image.

[0232] In operation S203 , an inverse Fourier transform is performed on the image frequency domain signal to obtain a first magnetic image.

[0233] According to some embodiments of the present disclosure, in operation S202, based on the two-dimensional k-space image, the image frequency domain signals at different moments in the two-dimensional k-space image are separated, and a k-space filter is constructed for each moment of the image, the center position of which is , with a width of W, which satisfies , that is, the filter width is less than or equal to the spatial frequency difference between the two fringes with the closest period and direction, to ensure that the separated signal will not be interfered by fringes in other directions; after applying the k-space filter to all cosine fringes, M two-dimensional k-space frequency domain signals are obtained, representing the frequency domain signals at different times, that is, the image frequency domain signals at different times are obtained.

[0234] According to some embodiments of the present disclosure, in operation S203, for the image frequency domain signals obtained at different moments, the zero frequency position of the two-dimensional frequency domain signal corresponding to each stripe is changed from Move to the origin of the two-dimensional k-space, and then perform inverse Fourier transform to obtain the real-space image encoded by each fringe, that is, the two-dimensional real-space magnetic field map at the corresponding moment, that is, the first magnetic image including multiple sub-two-dimensional real-space images corresponding to multiple moments.

[0235] According to some embodiments of the present disclosure, k-space is an abstract space (either three-dimensional or two-dimensional) in which data points represent the spatial frequency information of an image. Spatial frequency k is described by three components, Kx, Ky, and Kz, corresponding to a three-dimensional frequency space. In a two-dimensional image, we typically only focus on components Kx and Ky. Each point in k-space corresponds to a combination of sinusoidal waves of varying frequencies, phases, and directions within the image. Therefore, k-space data can be considered a representation of the image in the frequency domain. When an image is acquired, it is actually a two-dimensional matrix consisting of a series of pixel values. These pixel values ​​represent the brightness or grayscale information of the image in the spatial domain. To analyze the frequency content of an image, a two-dimensional Fourier transform can be performed on the image. This process converts the image's pixel values ​​into complex frequency coefficients, which describe the magnitude and phase of the different frequency components within the image. The result of the transform is a two-dimensional k-space image. In a k-space image, low-frequency components (corresponding to large-scale structures within the image) are typically located in the center, while high-frequency components (corresponding to edges and details within the image) are distributed in the edge regions. By analyzing k-space images, we can better understand the frequency distribution and characteristics of images. At the same time, we can also use k-space data to optimize the image reconstruction process and improve image resolution and contrast.

[0236] Those skilled in the art will appreciate that the features described in the various embodiments and / or claims of this disclosure may be combined and / or coupled in various ways, even if such combinations and / or couplings are not explicitly described in this disclosure. In particular, the features described in the various embodiments and / or claims of this disclosure may be combined and / or coupled in various ways without departing from the spirit and teachings of this disclosure. All such combinations and / or couplings are intended to fall within the scope of this disclosure.

[0237] The embodiments of the present disclosure are described above. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of the present disclosure. Although each embodiment has been described separately above, this does not mean that the measures in each embodiment cannot be used in combination to advantage. The scope of the present disclosure is defined by the appended claims and their equivalents. Without departing from the scope of the present disclosure, those skilled in the art may make various substitutions and modifications, which should all fall within the scope of the present disclosure.

Claims

1. A wide-field dynamic magnetic imaging device, wherein: include: A probe assembly including a diamond containing NV color centers; A microwave magnetic field assembly, adapted to generate a uniform microwave field and a uniform bias magnetic field near the diamond to regulate the spin energy level and quantum state evolution of the diamond; a laser modulation component adapted to output an initial uniform pulsed laser to excite the diamond to emit fluorescence, wherein the fluorescence includes magnetic field information of the sample to be measured; a stripe light modulation component adapted to modulate the initial uniform pulse laser to output a stripe pulse laser so that the fluorescence emitted by the diamond is stripe fluorescence; or to directly modulate the fluorescence emitted by the diamond into stripe fluorescence; A fluorescence detection component, adapted to perform spatial imaging of the stripe fluorescence to obtain magnetic field information of the sample to be tested, and further obtain an initial magnetic image of the sample to be tested; as well as a data processing component adapted to perform Fourier transform and inverse Fourier transform on the initial magnetic image to obtain a first magnetic image; The initial magnetic image includes a two-dimensional real-space image obtained by superimposing sub-two-dimensional real-space images obtained at multiple moments, and the first magnetic image includes multiple sub-two-dimensional real-space images corresponding to the multiple moments respectively.

2. The wide-field dynamic magnetic imaging device according to claim 1, wherein: The surface of the diamond containing NV color centers is flat and contains multiple NV color centers, and the multiple NV color centers form a thin layer inside the diamond; The depth difference between two adjacent NV color centers is less than 10 microns, and the distance between two adjacent NV color centers in the horizontal direction is less than the optical diffraction limit.

3. The wide-field dynamic magnetic imaging device according to claim 2, wherein: The laser modulation assembly comprises: A laser, suitable for outputting initial continuous laser; A first half-wave plate is used to adjust the polarization direction of the initial continuous laser to obtain a first continuous laser; an acousto-optic modulator group, adapted to modulate the first continuous laser to obtain an initial pulse laser, so as to improve an on / off ratio of the initial pulse laser; a lens assembly, adapted to adjust the beam diameter of the initial pulsed laser; and The beam shaper is adapted to convert the initial pulse laser beam into a flat-top beam with uniform light intensity distribution, so as to output the initial uniform pulse laser.

4. The wide-field dynamic magnetic imaging device according to claim 3, wherein: The stripe light modulation component includes: A digital micromirror device, adapted to diffract the initial uniform pulsed laser into multiple beams of parallel light propagating in different directions; a 4f optical system adapted to convert the plurality of parallel light beams into striped light, wherein the striped light presents a two-dimensional distribution of alternating bright and dark stripes on an output plane; and A filter is provided in the 4f optical system, and the filter is suitable for filtering out stray light in the multiple beams of parallel light.

5. The wide-field dynamic magnetic imaging device according to any one of claims 1 to 4, wherein: The fluorescence detection component includes: an imaging lens adapted to focus the fluorescence to form a fluorescence image; a multi-stage filter adapted to filter out stray light signals and laser light reflected from the diamond surface; and The fluorescence detector is adapted to convert the fluorescence signal into an electrical signal so as to obtain the magnetic field information of the sample to be tested.

6. The wide-field dynamic magnetic imaging device according to claim 5, wherein: The probe assembly further includes: The uniform radiation structure is suitable for providing a microwave field to change the spin quantum state of the NV color center in the diamond.

7. The wide-field dynamic magnetic imaging device according to claim 6, wherein: The microwave magnetic field assembly comprises: A microwave source, suitable for generating initial microwaves of specific frequency and power; A microwave beam splitter, adapted to split the initial microwave into two first microwaves of equal power and 90° phase difference; A microwave switch, adapted to control the on / off of the transmission paths of the two first microwaves; A microwave combiner, adapted to combine two of the first microwaves into one second microwave; a microwave amplifier, adapted to amplify the power of the second microwave to obtain a third microwave, wherein the third microwave enters the uniform radiation structure; an isolator, adapted to prevent the third microwave from being reflected and entering the microwave amplifier; Impedance matching, adapted to reduce losses during the third microwave transmission process; and A magnetic field source is suitable for providing a uniform bias magnetic field.

8. The wide-field dynamic magnetic imaging device according to claim 7, wherein: Also included are temperature control components, including: a temperature monitor adapted to monitor the temperature of the diamond surface, a temperature-controlled box, suitable for housing the probe assembly; and The temperature controller is adapted to control the temperature inside the temperature control box to be stable at a target temperature.

9. A wide-field dynamic magnetic imaging method, using the wide-field dynamic magnetic imaging device according to any one of claims 1 to 8, wherein: The method comprises: Using a laser modulation component to output an initial uniform pulsed laser to excite diamond containing NV color centers to emit fluorescence, wherein the fluorescence includes magnetic field information of the sample to be tested; Using a stripe light modulation component to modulate the initial uniform pulse laser to output a stripe pulse laser, so that the fluorescence emitted by the diamond is stripe fluorescence; or modulating the fluorescence emitted by the diamond into stripe fluorescence; Using a microwave magnetic field assembly to generate a uniform microwave field and a uniform bias magnetic field at the position of the diamond to regulate the spin energy level and quantum state evolution process of the diamond; Performing spatial imaging of the stripe fluorescence using a fluorescence detection component to obtain magnetic field information of the sample to be tested, thereby obtaining an initial magnetic image of the sample to be tested; Performing Fourier transform and inverse Fourier transform on the initial magnetic image using a data processing component to obtain a first magnetic image; The initial magnetic image includes a two-dimensional real-space image obtained by superimposing sub-two-dimensional real-space images obtained at multiple moments, and the first magnetic image includes multiple sub-two-dimensional real-space images corresponding to the multiple moments respectively.

10. The wide-field dynamic magnetic imaging method according to claim 9, wherein: The performing Fourier transform and inverse Fourier transform on the initial magnetic image by using a data processing component to obtain a first magnetic image comprises: Performing Fourier transform processing on the initial magnetic image to obtain a frequency domain signal, wherein the frequency domain signal is represented in the form of a two-dimensional k-space image; acquiring image frequency domain signals at different moments according to the two-dimensional k-space image; Perform inverse Fourier transform on the image frequency domain signal to obtain a first magnetic image.

Images