Integrated detection system and nondestructive detection method based on solid-state spinning color center

Abstract

The invention provides an integrated detection system based on a solid-state spinning color center and a nondestructive detection method. The integrated detection system comprises an excitation light module, a wide-field branch, a confocal branch, a first beam splitter, a first double-color sheet, an objective lens, a probe comprising a solid-state spin color center, a first filter, a guide element, a first photoelectric detection light path, a second photoelectric detection light path, a wide-field imaging light path, a differential module and a microwave module. The excitation light module outputs two paths of excitation light in a switchable manner, the two paths of excitation light are respectively transmitted to a confocal branch and a wide-field branch, the two paths of light beams are guided to the same laser excitation and fluorescence detection light path through a first beam splitter, and then collected fluorescence is guided to a first photoelectric detection light path or a wide-field imaging light path through a guide element; meanwhile, after the exciting light output by the confocal branch is split by the first beam splitter, one part of the exciting light is used for excitation, and the other part of the exciting light is used for difference, so that common-mode noise can be reduced; wide-field imaging and confocal integration can realize real-time switching.

Description

Technical Field

[0001] This invention relates to the field of quantum measurement, and in particular to an integrated detection system and non-destructive testing method based on solid-state spin color centers. Background Technology

[0002] Existing quantum measurement systems are generally divided into wide-field imaging systems and confocal systems. Wide-field imaging systems combine ODMR (optically probed magnetic resonance) technology with microscopic imaging technology, simultaneously satisfying wide-field and high spatial resolution magnetic imaging requirements. They have broad application prospects in fields such as integrated circuit structure and function analysis, chip electromagnetic compatibility, and biomedical imaging. Confocal systems, on the other hand, can achieve point measurements. In practice, these two systems are separate. For the same object being measured, because the diameter and intensity of the excitation beams used in wide-field and confocal systems differ, and the methods of fluorescence collection also differ, a single system cannot be used. Two separate systems must be built to achieve both wide-field and confocal functions, making operation cumbersome, setup and debugging time lengthy, and preventing real-time measurement of both functions. Summary of the Invention

[0003] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide an integrated detection system and non-destructive testing method based on solid-state spin centers, which solves the problem that in the prior art, the wide-field imaging system and the confocal system are separate. For the same detection object, two separate systems need to be built to realize the two functions of wide field and confocal, which is cumbersome to operate and cannot achieve real-time switching.

[0004] To achieve the above and other related objectives, a first aspect of the present invention provides an integrated detection system based on a solid-state spin center, comprising: an excitation light module, a wide-field branch, a confocal branch, a first beam splitter, a first dichroic filter, an objective lens, a probe containing a solid-state spin center, a first filter, a guiding element, a first photoelectric detection optical path, a second photoelectric detection optical path, a wide-field imaging optical path, a differential module, and a microwave module. Excitation light module, used for switchable delivery of excitation light to wide-field branch and confocal branch; The wide-field branch is used to receive and process the excitation light to obtain a beam that satisfies wide-field imaging. The confocal branch is used to receive the excitation light and process it to obtain a beam that satisfies the requirements of confocal detection. The first beam splitter receives two excitation beams output from the wide-field branch and the confocal branch respectively, and splits a portion of each excitation beam to the first dichroic filter. The first dichroic filter reflects the excitation light to the objective lens, which transmits it to the probe. The fluorescence generated by the probe is then transmitted sequentially through the objective lens, the first dichroic filter, and the first filter to the guiding element. When the excitation light is received in the confocal branch, the fluorescence is guided to the first photodetector optical path and collected and converted into a first electrical signal. Alternatively, when the excitation light is received in the wide-field branch, the fluorescence is guided to the wide-field imaging optical path and collected to form an image, thus obtaining imaging data. The second photoelectric detection optical path receives another portion of the light from the confocal branch, which is split off by the first beam splitter, and converts it into a second electrical signal. The differential module is connected to the first photoelectric detection optical path and the second photoelectric detection optical path. It is used to receive the first electrical signal and the second electrical signal, and to perform differential processing on them to obtain a differential electrical signal. The microwave module is used to radiate microwaves to the probe.

[0005] Furthermore, the excitation light module includes two excitation light sources for delivering excitation light to the wide-field branch and the confocal branch in a one-to-one correspondence; or the excitation light module includes an excitation light source, a first reflector, and a second reflector; the first reflector is a rotatable reflector, when the first reflector is rotated to a first state, the excitation light output by the excitation light source is reflected by the first reflector and transmitted to the second reflector, and then reflected to one of the branches; when the first reflector is rotated to a second state, the excitation light output by the excitation light source is transmitted in a straight line to the other branch.

[0006] Furthermore, when the excitation light output by the excitation light module to the wide-field branch is laser light, the wide-field branch includes a first condenser lens; when the excitation light output by the excitation light module to the wide-field branch is incoherent light, the wide-field branch includes one or more condenser lenses; when the excitation light output by the excitation light module to the confocal branch is laser light, the confocal branch includes two condenser lenses.

[0007] Furthermore, the guiding element is a fourth reflector, which is flip-up. When the fourth reflector is rotated to the first state, the light filtered by the first filter is transmitted to its reflective surface and reflected to one of the first photoelectric detection optical path and the wide-field imaging optical path. When the fourth reflector is rotated to the second state, the light filtered by the first filter is transmitted in a straight line to the other of the first photoelectric detection optical path and the wide-field imaging optical path.

[0008] Furthermore, it also includes a bias magnetic field module for applying a bias magnetic field to the probe.

[0009] Furthermore, it also includes an excitation light adjustment module, which receives the first electrical signal and the differential signal, and adjusts the excitation light power transmitted to the second photoelectric detection optical path so that the ratio of the differential electrical signal to the first electrical signal is a preset value.

[0010] Furthermore, the excitation light adjustment module includes a control module, a driver, and a gradient filter or polarizer. The gradient filter or polarizer is located on the transmission optical path from the excitation light to the second photodetector optical path. The control module is used to collect differential electrical signals and a first electrical signal, and control the driver to move the gradient filter or rotate the polarizer according to the differential electrical signals and the first electrical signal, thereby changing the power of the excitation light by changing the position of the excitation light passing through it. Alternatively, the excitation light adjustment module includes an electric aperture and a control module. The electric aperture is located on the transmission optical path from the excitation light to the second photodetector optical path, and the control module controls the aperture area of ​​the electric aperture that allows light to pass through according to the differential electrical signals and the first electrical signal, thereby changing the power of the excitation light passing through.

[0011] Furthermore, it also includes an illumination module and a second beam splitter. The second beam splitter is located between the first dichroic filter and the first filter. The illumination light output by the illumination module illuminates the second beam splitter. A portion of the light split by the second beam splitter is transmitted to the first dichroic filter, and then sequentially guided by the first dichroic filter and transmitted through the objective lens to illuminate the object side of the objective lens. The illumination light reflected from the object side sequentially passes through the objective lens, guided by the first dichroic filter, split by the second beam splitter, and transmitted through the first filter before being guided by the guiding element into the wide-field imaging optical path for imaging.

[0012] Furthermore, the wavelength of the illumination light is different from the fluorescence generated by the probe. The guiding element is a second dichroic filter, which is flip-up. When transmitting excitation light to the confocal branch and turning on the illumination, the second dichroic filter is rotated to the first state. The fluorescence filtered by the first filter is reflected by the second dichroic filter to the first photoelectric detection optical path, and the illumination light is transmitted through the second dichroic filter to the wide-field imaging optical path. When transmitting excitation light to the wide-field branch, the second dichroic filter is rotated to the second state. The fluorescence filtered by the first filter is transmitted in a straight line to the wide-field imaging optical path.

[0013] To achieve the above and other related objectives, a second aspect of the present invention provides a non-destructive testing method based on solid-state spin centers, employing an integrated testing system based on solid-state spin centers as described in any one of the first aspects, wherein the integrated system further includes a moving device, on which a stage is used to place the sample to be tested and to control the movement of the sample; and includes a data processing module connected to a differential module and a wide-field imaging optical path, for acquiring differential electrical signals and reading imaging data or images, and processing and analyzing the differential electrical signals and imaging data or images, and connected to a microwave module for controlling the microwave frequency radiated thereon; the method includes: The sample to be tested is placed under the probe, and the sample surface is scanned point by point using the probe. At each scanning point, ODMR measurement is performed using confocal detection to obtain the magnetic field strength at each scanning point. The magnetic field strength distribution formed by the magnetic field strength of all scanning points is used to determine whether there are defects in the sample. If defects are found, the area where the defects are located is taken as the target area for further detection. ODMR measurement is then performed on the target area using wide-field imaging to obtain the magnetic field strength distribution of the target area, thereby obtaining the distribution information of the defects.

[0014] As described above, the integrated detection system and non-destructive testing method based on solid-state spin centers of the present invention have the following beneficial effects: The present invention sets up an excitation light module that can switchably output two excitation lights, which are respectively transmitted to a confocal branch and a wide-field branch to obtain beams that satisfy confocal and wide-field imaging respectively. The two beams are guided by a first beam splitter to the same laser excitation and fluorescence detection optical path, and then the collected fluorescence is guided by a guiding element to the photoelectric detection optical path or the wide-field imaging optical path. At the same time, after the first beam splitter splits the excitation light output from the confocal branch, a part is used for excitation and the other part is used for differential, which can reduce common-mode noise in confocal detection. Thus, the integration of wide-field imaging and confocal is achieved, which is more convenient than rebuilding separately in the prior art, avoids repeated debugging during the switching process, and can achieve real-time switching. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the first structure of an integrated detection system; Figure 2 This is a schematic diagram of the second structure of the integrated detection system; Figure 3 This is a schematic diagram of the third structure of the integrated detection system; Figure 4 This is a schematic diagram of the fourth structure of the integrated detection system; Figure 5 This is a schematic diagram of the fifth structure of the integrated detection system; Figure 6 The diagram shown is a structural schematic of an excitation light adjustment module.

[0016] Component labeling: 1—Excitation light module; 11—First excitation source; 12—Second excitation source; 13—First reflector; 14—Second reflector; 2—Wide field branch; 21—First condenser lens; 22—TIR lens; 23—Convex lens; 3—Confocal branch; 31—Third reflector; 32—Second condenser lens; 33—Third condenser lens; 4—First beam splitter; 5—First dichroic filter; 6—Objective lens; 7—Probe; 8—First filter; 9—Guiding element; 10—First photodetector optical path; 101—Fourth condenser lens; 102—First photodetector; 20—Second photodetector optical path; 201—Second photodetector; 2 02—Fifth condenser lens; 30—Wide-field imaging optical path; 301—Imaging camera; 302—Imaging lens; 303—Third filter; 40—Differential module; 50—Microwave module; 501—Microwave generation module; 502—Microwave antenna; 60—Magnet; 70—Illumination light module; 701—Illumination source; 702—Sixth condenser lens; 80—Second beam splitter; 90—Fifth reflector; 100—Excitation light adjustment module; 1001—Control module; 1002—Driver; 1003—Graduated filter; 1004—Polarizer; 1005—Motorized aperture; 200—Moving device; 300—Data processing module; 400—Sample. Detailed Implementation

[0017] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, unless otherwise specified, the following embodiments and features described therein can be combined with each other.

[0018] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Therefore, the illustrations only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0019] Example 1: As Figure 1 As shown, this embodiment provides an integrated detection system based on solid-state spin centers, including: an excitation light module 1, a wide-field branch 2, a confocal branch 3, a first beam splitter 4, a first dichroic filter 5, an objective lens 6, a probe containing a solid-state spin center 7, a first filter 8, a guiding element 9, a first photoelectric detection optical path 10, a second photoelectric detection optical path 20, a wide-field imaging optical path 30, a differential module 40, and a microwave module 50; Excitation light module 1 is used to switchably deliver excitation light to wide-field branch 2 and confocal branch 3; Wide-field branch 2 is used to receive the excitation light and process it to obtain a beam that satisfies wide-field imaging. Confocal branch 3 is used to receive the excitation light and process it to obtain a beam that satisfies confocal detection. The first beam splitter 4 receives two excitation beams output from the wide-field branch 2 and the confocal branch 3 respectively, and splits a portion of each excitation beam to the first dichromatic filter 5; The first dichroic filter 5 guides the excitation light to the objective lens 6, which transmits it to the probe 7. The fluorescence generated by the probe 7 is then transmitted sequentially through the objective lens 6, guided by the first dichroic filter 5, and transmitted through the first filter 8 to the guiding element 9. When the excitation light is received in the confocal branch 3, the fluorescence is guided to the first photodetector optical path 10 and collected and converted into a first electrical signal. Alternatively, when the excitation light is received in the wide-field branch 2, the fluorescence is guided to the wide-field imaging optical path 30 and collected for imaging. The second photoelectric detection optical path 20 receives another portion of light from the confocal branch 3, which is split off by the first beam splitter 4, and converts it into a second electrical signal. The differential module 40 is connected to the first photoelectric detection optical path 10 and the second photoelectric detection optical path 20. It is used to receive the first electrical signal and the second electrical signal, and to perform differential processing on them to obtain a differential electrical signal. Microwave module 50 is used to radiate microwaves to probe 7.

[0020] In this embodiment, wide-field branch 2 and confocal branch 3 are set up to receive the excitation light required for wide-field imaging and confocal detection, respectively. The two detection modes are switched by switching the excitation light. After the excitation light is guided to the same laser excitation and fluorescence detection optical path by the first beam splitter 4, the collected fluorescence is guided to the photoelectric detection optical path 10 or the wide-field imaging optical path 30 by the guiding element 9. At the same time, after the excitation light output from the confocal branch is split by the first beam splitter 4, part is used for excitation and the other part is used for differential, which can reduce common-mode noise in confocal detection. The objective lens is used as an imaging device in wide-field and as a convex lens in confocal, thus realizing the integration of wide-field imaging and confocal. When switching between the two functions, the position of the imaging plane does not change. The switching between the two detection modes is more convenient than the separate reconstruction in the prior art, avoiding repeated debugging during the switching process and realizing real-time switching.

[0021] The excitation light module 1 in this embodiment includes a first excitation light source 11 and a second excitation light source 12. The first excitation light source 11 is used to deliver excitation light to the wide-field branch 2, and the second excitation light source 12 is used to deliver excitation light to the confocal branch 3. Thus, excitation light can be delivered to different branches as needed by turning on the corresponding excitation light sources, thereby achieving the switching of different detection modes.

[0022] The excitation light can be a laser. The excitation beam output by the first excitation source 11 is a coarse beam with a diameter of 10mm-25mm to meet the wide-field requirement. The excitation beam output by the second excitation source 12 is a fine beam with a diameter of 2-6mm. The wide-field branch includes a first condenser lens 21. The laser beam is focused by the first condenser lens 21 and then transmitted to the first beam splitter 4. The first condenser lens 21 shapes the beam to obtain a beam size that meets the requirements of the subsequent objective lens and to achieve wide-area imaging in conjunction with the objective lens. The first condenser lens 21 can be a biconvex lens. When the size and collimation of the laser beam delivered by the excitation source meet the requirements of confocal detection, the confocal branch can be configured as follows: Figure 1 As shown, no further processing of the beam is required; if further collimation of the laser is needed, it can be done as follows: Figure 2 As shown, two condenser lenses are arranged on the confocal branch. These condenser lenses can be plano-convex lenses, ensuring that the light output after transmission through the two lenses is parallel, and that the diameter of the beam entering the objective lens is smaller than the objective lens's entrance aperture. To simplify the overall system structure, when the second excitation source 12 is positioned on the same side as the first excitation source 11, it can be arranged as follows: Figure 2 As shown, a third reflector 31 is set in the confocal branch 3, and the laser emitted from the left side is reflected by the third reflector 31 and transmitted to the first beam splitter 4.

[0023] The excitation light supplied to the wide-field branch can also be incoherent light, such as light generated by an LED. Compared to highly coherent lasers, this results in a more uniform light spot, avoiding interference fringes in the imaging process. In this case, the wide-field branch can include one or more condenser lenses. The condenser lens can be a TIR lens (total internal reflection lens). Figure 2 The example provided illustrates the use of a TIR lens 22 to converge and collimate the incoherent light emitted from the first excitation source 11, thereby reducing the divergence angle and increasing the light intensity. Alternatively, as shown... Figure 4 As shown, a combination of TIR lens 22 and convex lens 23 is used. After the collimated beam emitted from the TIR lens is focused by convex lens 23 and combined with the subsequent objective lens, the spot size of the objective lens's object-side imaging surface can be increased to meet the requirements of wide-field imaging. Convex lens 23 can be a plano-convex lens or a biconvex lens. Alternatively, the TIR lens can be combined with a hemispherical lens.

[0024] Based on the beam-splitting principle of the beam splitter, the two excitation beams output from the wide-field branch 2 and the confocal branch 3 are transmitted to two surfaces of the first beam splitter 4. One beam is transmitted through transmission to the first dichroic filter 5, and the other beam is reflected to the first dichroic filter 5. In this embodiment, the excitation beam from the wide-field branch is transmitted through the first beam splitter 4, while the excitation beam from the confocal branch is reflected by the first beam splitter 4. Alternatively, it can be as follows: Figure 3 The diagram illustrates the interchangeable scenario. The splitting ratio of the first beam splitter 4 ensures that the ratio of the optical power transmitted to the wide-field branch of the first dichroic filter 5 to its total optical power is greater than 1 / 2, preferably 9 / 10, allowing more excitation light to be used for wide-field imaging, for example... Figure 1 The splitting ratio of the first beam splitter 4 is set to T:R = 9:1. Figure 3 With the beam splitting ratio set to T:R=1:9, the light power transmitted from the excitation light from the confocal branch to the first dichroic filter 5 after reflection by the beam splitter accounts for 1 / 10 of its total power, which is still sufficient to meet the detection requirements.

[0025] When the excitation light output from the confocal branch 3 illuminates the first beam splitter 4, a portion of the split light is transmitted to the first dichroic filter 5, and the other portion is transmitted to the second photodetector optical path 20 where it is collected and converted into a second electrical signal. In this embodiment, the portion reflected by the first beam splitter is transmitted to the first dichroic filter 5 for excitation, while the transmitted portion serves as reference excitation light and is transmitted to the second photodetector optical path 20 where it is collected and converted into a second electrical signal for differential noise reduction. Alternatively, it can be... Figure 3 As shown, when the portion transmitted by the first beam splitter 4 is transmitted to the first dichroic filter 5, the reflected portion is transmitted to the second photoelectric detection optical path 20 and collected and converted into a second electrical signal.

[0026] In this embodiment, the first dichroic filter 5 reflects the excitation light from the first beam splitter 4 to the objective lens 6, and transmits the fluorescence from the objective lens 6 to the first filter 8. The transmission and reflection can also be as follows: Figure 3 The opposite of what is described in the text.

[0027] Guide element 9 can be as follows Figure 1The diagram shows the fourth reflecting mirror, which is flip-up. When the fourth reflecting mirror is rotated to the first state, the light filtered by the first filter 8 is transmitted to its reflective surface and reflected to one of the first photodetector optical path 10 and the wide-field imaging optical path 30. When the fourth reflecting mirror is rotated to the second state, the light filtered by the first filter 8 is transmitted in a straight line to the other of the first photodetector optical path 10 and the wide-field imaging optical path 30. In the first state, the mirror surface is placed at a 45-degree angle to the light transmission path. In the second state, the mirror surface is placed parallel to the direction of the light transmission path (the reflecting mirror shown by the dashed line in the figure), and the light does not illuminate the reflecting mirror but is transmitted in a straight line. In this embodiment, in the first state, the light filtered by the first filter 8 illuminates the reflecting mirror and is reflected to the first photodetector optical path 10. In the second state, the light filtered by the first filter 8 is transmitted in a straight line to the wide-field imaging optical path 30. The first filter 8 is selected to filter out the fluorescence wavelength. Taking the diamond nitrogen-vacancy color center as an example, an absorption-type long-pass filter with a cutoff wavelength of 637nm-640nm can be selected.

[0028] To simplify the overall system structure, it can also be done as follows: Figure 2 As shown, a fifth reflector 90 is placed after or before the first filter 8 to reflect light to the same side as the excitation source.

[0029] In this embodiment, the objective lens 6 can be an objective lens turret. By rotating the turret, objectives of different magnifications can be placed in the optical path. For example, in wide-field imaging, low magnifications such as 10x, 20x, and 50x can be selected, and in confocal imaging, high magnifications such as 100x can be selected, which can obtain a smaller focused spot and improve resolution during scanning.

[0030] The first photoelectric detection optical path 10 includes a fourth condenser lens 101 and a first photodetector 102. The light filtered by the first filter 8 is focused by the fourth condenser lens 101 and then collected and detected by the first photodetector 102 to form a fluorescent electrical signal. The fourth condenser lens 101 is a biconvex lens.

[0031] The second photoelectric detection optical path 20 includes a second photodetector 201, used to convert the collected excitation light into a second electrical signal. Alternatively, as shown... Figure 2 A fifth focusing lens 202 is added to converge and collect the light.

[0032] The wide-field imaging optical path 30 includes an imaging camera 301, which collects and images the light filtered by the first filter 8. The imaging camera 301 can be a CCD or a CMOS sensor. Alternatively, when the objective lens 6 is at infinity, it also includes an imaging lens 302, such as... Figure 2 As shown, the imaging lens 302, which can be an FA lens or a tube lens, is located between the imaging camera 301 and the guide element 9 and is used to converge light. The imaging data output by the imaging camera includes at least the grayscale value at each pixel.

[0033] The microwave module 50 includes a microwave generation module 501 and a microwave antenna 502. The microwave generation module 501 can, for example, include a microwave source, a microwave switch, a microwave amplifier, and a microwave circulator connected in sequence. The microwaves generated by the microwave source are transmitted to the microwave antenna and then radiated to the probe 7 by the microwave antenna 502. In this embodiment, the probe 7 is a sheet-like diamond structure with dimensions of tens or hundreds of micrometers or millimeters, enabling wide-field imaging. The sheet-like diamond can also be used for confocal detection; alternatively, when performing confocal detection, the sheet-like diamond can be replaced with granular material with dimensions of several micrometers or tens of micrometers. Of course, the color center can also be selected from one of the following: diamond germanium vacancy color centers, diamond silicon vacancy color centers, silicon carbide double vacancy color centers, silicon carbide silicon vacancy color centers, or hexagonal boron nitride boron vacancy color centers, all of which exhibit photoluminescence effects. The microwave antenna uses a microstrip antenna, such as a coplanar waveguide. The probe is located in or below the central aperture of the coplanar waveguide, and light is irradiated onto the diamond through the central aperture.

[0034] The wide-field imaging and confocal detection methods in this embodiment can both be applied to the precise measurement of magnetic fields, currents, temperatures, etc. The specific principle behind these applications is that changes in these measured quantities affect the resonant frequency of solid-state spin centers. Taking the measurement of magnetic fields using diamond NV centers as an example, the Zeeman splitting effect of the ground state energy level of the NV center caused by the external magnetic field is utilized. Then, the frequency shift of the resonant point of the ODMR spectrum is detected. Finally, the frequency shift is converted into magnetic field strength using the gyromagnetic ratio of the NV center electrons, thereby achieving the purpose of detecting the external magnetic field. Confocal detection is used for single-point detection, obtaining the magnetic field strength at a single point through ODMR measurement. Based on the micron or nanometer-level spatial resolution and the ultra-high sensitivity of magnetic measurement at the picotesla level, it can also be used for scanning detection. Wide-field imaging, on the other hand, is applied to the detection of a large field of view. It is a collection of multiple pixels, achieving a spatial resolution of hundreds of nanometers and high sensitivity at the microtesla level.

[0035] In this embodiment, in some cases, such as when the direction of the magnetic field to be measured is known, the desired ODMR spectral line can be obtained by adjusting the angle between the magnetic field direction and the axis of the color center. In other cases, such as when the direction of the magnetic field to be measured is unknown or when detecting weak magnetic fields, a bias magnetic field module can be further added to apply a bias magnetic field to the probe. This is used to adjust the resonance peak generated by the color center, or to ensure that the detection of weak magnetic fields by the color center operates in the linear region, or to adjust the detection frequency band to improve the sensitivity of weak magnetic field detection. The bias magnetic field module exemplarily includes a Helmholtz coil or, for example, a... Figure 2 Magnet 60 is shown.

[0036] Example 2: Figure 3As shown, based on Embodiment 1, this embodiment further includes an illumination light module 70 and a second beam splitter 80. The second beam splitter 80 is located between the first dichroic film 5 and the first filter 8. The illumination light output by the illumination light module 70 illuminates the second beam splitter 80. A portion of the light split by the second beam splitter 80 is transmitted to the first dichroic film 5, then guided by the first dichroic film 5, transmitted through the objective lens 6, and then illuminates the object side of the objective lens. The illumination light reflected from the object side is transmitted through the objective lens 6, guided by the first dichroic film 5, split by the second beam splitter 80, transmitted through the first filter 8, and then guided by the guiding element 9 into the wide-field imaging optical path for imaging.

[0037] In this embodiment, the second beam splitter 80 reflects a portion of the illumination light from the illumination module 70 and directs it to the first dichroic filter 5. A portion of the illumination light guided from the first dichroic filter 5 to the first filter 8 is transmitted through the second beam splitter 80 to the first filter 8. The reflection and transmission methods can also be reversed. The second beam splitter 80 is of a high-transmittance, low-reflection type to transmit more illumination light for imaging; for example, a beam splitter with a splitting ratio (T:R) of 9:1 is used. The illumination light is white light or light in a wavelength range adjacent to or equal to that of fluorescence. For example, the photoluminescence of diamond NV color centers is red light (wavelength 637-800nm). Red light, for example, above 600nm, is preferred to reduce heat generation at the same brightness. Since the photoluminescence of the diamond NV color center is red light (wavelength 637-800nm), and the first filter 8 also filters out the corresponding red light, the imaging camera is adapted to receive the red light. If the illumination on the object side is weak, the object side observed on the image side will not be clear enough, thus making it impossible to determine the state of the object under test. This embodiment adds illumination to the optical path to supplement the illumination. This can be used to adjust the object under test before placing the diamond on the object side, observe the state of the object under test, and facilitate the adjustment of the position of the object under test. After the adjustment is completed, the diamond is placed between the object under test and the object side of the objective lens, and the illumination source can be turned off to proceed to the subsequent detection steps. In this mode, the wide-field imaging optical path can be used for illumination on the object side and wide-field imaging of the object under test under the probe detection. The three modes of illumination, wide-field imaging, and confocal detection can be switched as needed. The operation is convenient, the real-time performance is strong, and the system integration is high, which is conducive to miniaturized applications.

[0038] For other solid-state spin centers, the excitation wavelength may differ. For example, for diamond nitrogen-vacancy centers and hexagonal boron nitride boron-vacancy centers, a 532nm green excitation light is generally used, while for silicon carbide double-vacancy centers, a 900-940nm excitation light is used. For other solid-state spin centers, such as silicon carbide silicon-vacancy centers, diamond germanium-vacancy centers, and diamond silicon-vacancy centers, corresponding excitation light can be used. Furthermore, the wavelengths of photofluorescence produced by different solid-state spin centers are not entirely the same. In this case, analogous to the selection of illumination light for diamond NV centers mentioned earlier, adjacent or identical wavelengths can be selected. For example, for silicon carbide double-vacancy centers producing fluorescence of 1000nm-1400nm, near-infrared light around 1000nm can be selected as the illumination light.

[0039] The lighting module 70 includes a lighting source 701 and a sixth condenser lens 702. The lighting light generated by the lighting source 701 is focused by the sixth condenser lens 702 and then transmitted to the second beam splitter 80. Alternatively, the sixth condenser lens 702 can be omitted, as long as illumination can be achieved. The lighting source 701 can be an incoherent light source, such as an LED.

[0040] The excitation light module in this embodiment includes a first excitation light source 11, a first reflector 13, and a second reflector 14. The first reflector 13 is a rotatable reflector. When the first reflector 13 is rotated to the first state, the excitation light output by the first excitation light source 11 is reflected by the first reflector 13 and transmitted to the second reflector 14, and then transmitted to one of the branches after reflection. When the first reflector 13 is rotated to the second state, the excitation light output by the excitation light source is transmitted in a straight line to the other branch. The first and second states are as described above and will not be repeated. In this embodiment, the excitation light when the first reflector 13 is in the first state is transmitted to the wide-field branch 2, and the excitation light when it is in the second state is transmitted to the confocal branch 3. A third reflector 31 is provided in the confocal branch 3 to reflect the excitation light to the first beam splitter 4. The two branches can also be reversed.

[0041] When using the same excitation source, the excitation light output by the first excitation source 11 is a coarse-beam laser to meet the wide-field requirement as much as possible. At the same time, in the confocal branch, the light is focused by the second condenser lens 32 and the third condenser lens 33 to obtain a beam that meets the requirements of confocal detection. The second condenser lens 32 and the third condenser lens 33 are preferably plano-convex lenses.

[0042] Example 3: Based on Example 2, the difference between this example and Example 2 is that the wavelength of the illumination light is different from the fluorescence generated by the probe, such as... Figure 4As shown, the guide element 9 is a second dichroic filter, and it is flip-up. When transmitting excitation light to the confocal branch 3 and activating the illumination module 70, the second dichroic filter is rotated to the first state. The fluorescence filtered by the first filter 8 is reflected by the second dichroic filter to the first photodetector optical path, and the illumination light is transmitted through the second dichroic filter to the wide-field imaging optical path. When transmitting excitation light to the wide-field branch 2, the second dichroic filter is rotated to the second state, and the fluorescence filtered by the first filter 8 is transmitted in a straight line to the wide-field imaging optical path. In the first state, the mirror surface of the second dichroic filter is placed at a 45-degree angle to the light transmission path. In the second state, the mirror surface of the second dichroic filter is placed parallel to the direction of the light transmission path (the dichroic filter drawn by the dashed line in the figure). The light does not illuminate the mirror, but is transmitted in a straight line.

[0043] In this embodiment, the first filter 8 can filter out wavelengths including illumination light and fluorescence, and is generally an absorption-type long-pass filter. Taking a diamond nitrogen-vacancy color center as an example, the fluorescence it produces is in the 637-800nm ​​range. Therefore, the illumination light is selected as red light below 637nm, which is different from the fluorescence wavelength, for example, a wavelength between 600nm and 637nm. The first filter 8 is an absorption-type long-pass filter with a cutoff wavelength of 600nm, and the second dual-color filter is an interference-type low-pass filter with a cutoff wavelength of 637nm. This means it transmits wavelengths below 637nm and reflects wavelengths above 637nm, thereby separating the two wavelengths. Furthermore, since both wavelengths are near the red light range, they can be matched with the same imaging camera.

[0044] Furthermore, the wide-field imaging optical path 30 also includes a flip-up third filter 303. When used to receive illumination light, the third filter 303 is in a state parallel to the optical path, meaning the illumination light does not pass through the third filter 303 but is transmitted in a straight line to the imaging lens 302. When used to receive imaging fluorescence, the third filter 303 is in a state perpendicular to the optical path. The fluorescence passes through the third filter, filtering out fluorescence above 637nm, which is then collected by the imaging lens 302. The third filter 303 is selected to filter out the fluorescence wavelength. Taking diamond nitrogen-vacancy color centers as an example, an absorption-type long-pass filter with a cutoff wavelength of 637nm-640nm can be selected.

[0045] Therefore, this embodiment can achieve simultaneous operation of confocal detection and illumination observation. Specifically, the confocal branch 3 in the integrated system transmits excitation light to the probe 7, while the illumination light module is activated to output illumination light. The fluorescence generated by the probe 7 is collected by the first photoelectric detection optical path 10 and converted into a first electrical signal, which is then imaged by the wide-field imaging optical path 30. Thus, during focused detection, the diamond and its surroundings can be observed in real time, facilitating the adjustment of the diamond or sample position; it can also be used to observe a large area in real time during focused detection scanning.

[0046] Example 4: Based on Example 1, Example 2, or Example 3, such as... Figure 4 As shown, this embodiment also includes an excitation light adjustment module 100, which is used to receive a first electrical signal and a differential signal, and adjust the excitation light power transmitted to the second photoelectric detection optical path so that the ratio of the differential electrical signal to the first electrical signal is a preset value.

[0047] When the magnetic field sensed by the quantum probe changes, the resulting fluorescence also changes. With a constant signal-to-noise ratio, the noise in the fluorescence changes accordingly, while the reference excitation light in the differential signal remains constant. This results in the differential processing not maximally reducing common-mode noise, leading to poor noise suppression and reduced sensitivity. This embodiment adjusts the excitation light power in the second photodetector optical path used for differential processing, maintaining the ratio of the differential signal to the first electrical signal at a preset value. This ensures that the common-mode noise of both the excitation light entering the second photodetector optical path changes equally with the fluorescence, thereby maximizing the reduction of common-mode noise in the differential processing.

[0048] In an exemplary solution, such as Figure 4 As shown, the excitation light adjustment module 100 includes an adjustment module 1001, a driver 1002, and a gradient filter 1003. The gradient filter 1003 is located on the transmission optical path from the excitation light to the second photodetector optical path. The adjustment module 1001 controls the driver 1002 to move the gradient filter 1003 according to the first electrical signal and the differential signal, thereby changing the power of the reference excitation light by adjusting the position of the reference excitation light passing through it. The gradient filter 1003 is a long strip block structure. The transmittance of the excitation light is different at different positions along its lateral moving surface. The driver 1002 is a micro stepper motor. The reference excitation light passes through the gradient filter 1003 and illuminates the second photodetector 201, forming a second electrical signal output. The control module 1001 calculates the ratio of the differential electrical signal to the first electrical signal and provides a feedback signal to control the micro stepper motor to perform the action. The micro stepper motor controls the lateral displacement of the gradient filter to change the transmittance of the excitation light. This process continues until the ratio of the differential electrical signal to the first electrical signal is a preset value.

[0049] For the control operation of the driver, the relationship between the moving distance of the gradient filter and the magnitude of the second electrical signal can be controlled by calibrating the driver, which includes the following steps: S1, setting the motor position to the initial position; S2, reading the current magnitude of the second electrical signal; S3, setting the driving moving distance and recording the magnitude of the second electrical signal at different distances; S4, fitting the relationship between the moving distance and the magnitude of the second electrical signal.

[0050] When the control module 1001 determines that the ratio of the differential electrical signal to the first electrical signal is not a preset value, it calculates the second electrical signal when the ratio is the preset value, and then transmits a feedback signal to the driver according to the aforementioned calibration relationship so that the driver can make adjustments. This operation is repeated until the ratio of the differential electrical signal to the first electrical signal is the preset value.

[0051] The preset value here can be set as needed, generally within 10%. The preset value here can be a fixed value or a range.

[0052] In another exemplary scheme, such as Figure 5 As shown, the excitation light adjustment module 100 includes a control module 1001, a driver 1002, and a polarizer 1004. The polarizer 1004 is located on the transmission optical path from the excitation light to the second photodetector optical path. The control module 1001 controls the driver 1002 to rotate the polarizer 1004 according to the first electrical signal and the differential signal, thereby changing the power of the reference excitation light by adjusting the polarization direction of the light that can pass through the polarizer. The circular polarizer can rotate around its mirror center. The driver is a rotary drive motor that can control the rotation of the polarizer. Since the polarizer only allows light with a specific polarization direction to pass through, its rotation will change the transmittance of the excitation light through the polarizer. The calibration of the relationship between the rotation angle of the driver and the magnitude of the second electrical signal can be referred to the aforementioned calibration method using a graded filter.

[0053] In the third exemplary scheme, such as Figure 6 As shown, the excitation light adjustment module 100 includes a control module 1001 and an electric aperture 1005. The control module 1001 controls the aperture area of ​​the electric aperture 1005 that allows light to pass through according to the first electrical signal and the differential signal, thereby achieving the purpose of adjusting the excitation light power. The electric aperture 1005 has its own driver. The calibration of the relationship between the rotation angle of its driver and the magnitude of the second electrical signal can refer to the calibration method using the graded filter described above.

[0054] Example 5: Based on any of the foregoing examples, such as Figure 5 As shown, the integrated detection system in this embodiment also includes a mobile device 200, on which a test sample 400 is placed and the test sample 400 can be moved; and a data processing module 300, connected to the differential module 40 and the wide-field imaging optical path 30, for acquiring differential electrical signals and reading imaging data or images, and processing and analyzing differential electrical signals and imaging data or images, and connected to the microwave module for controlling the microwave frequency radiated by it.

[0055] The sample to be tested is placed on the support platform of the moving device, positioned below the probe. By moving the sample, the probe can scan the sample surface. The moving device 200 can employ a three-dimensional precision adjustment device. The data processing module 300 can calculate the magnetic field and obtain the magnetic field distribution based on the electrical signal and imaging data.

[0056] Based on the integrated detection system based on solid-state spin centers in this embodiment, this embodiment also provides a non-destructive testing method based on solid-state spin centers, including: placing the sample to be tested under the probe, using the probe to scan the sample surface point by point, and performing ODMR measurement at each scanning point using confocal detection to obtain the magnetic field strength at each scanning point. The magnetic field strength distribution formed by the magnetic field strength of all scanning points is used to determine whether there is a defect in the sample. If there is a defect, the area where the defect is located is taken as the target area for further detection, and then ODMR measurement is performed on the target area using wide-field imaging to obtain the magnetic field strength distribution of the target area, thereby obtaining the distribution information of the defect.

[0057] In the confocal detection method, excitation light is transmitted from the confocal branch 3 to the probe 7. The fluorescence generated by the probe 7 is collected and converted into an electrical signal by the first photodetector optical path 10. The probe used can be the same as the wide-field probe, or a small-sized granular probe can be used. The probe can be fixed by means of an optical fiber probe, i.e., the probe is placed on the end face of the optical fiber, and then the optical fiber is clamped by a clamp, so that the probe is fixed under the objective lens. When switching probes, the distance from the object plane of the objective lens to the diamond lens must remain unchanged. The magnetic field strength obtained at each scanning point in this confocal detection method refers to the ODMR measurement performed by the frequency sweep method for each scanning point when performing ODMR measurement using the microwave frequency sweep method. The ODMR spectrum of the differential electrical signal changes with the microwave frequency is obtained, and the magnetic field strength at each scanning point is calculated from the resonance frequency on the spectrum. Finally, the magnetic field strengths of each scanning point are collected into a graph to form a magnetic field strength distribution. The defect points are judged based on the distribution of magnetic field strength. For example, if the magnetic field strength of a certain part is abnormal, greater or less than the normal value, it indicates that a defect exists. The ODMR spectral plotting, magnetic field calculation, magnetic field intensity distribution map formation, and defect point identification in this part are all implemented by the data processing module 300.

[0058] Of course, the fixed-frequency method can also be used to perform ODMR measurements. Based on the principle that changes in magnetic field strength cause shifts in ODMR spectral lines, a certain frequency point is selected. This fixed frequency point is preferably the point where the slope of the spectral line on one side of any resonance peak is the largest. Moreover, within the half-width range of the fixed frequency point, the spectral line is approximately linear, that is, the change in magnetic field and the change in fluorescence are linear. Therefore, different magnetic field strengths can correspond to different fluorescence intensities. The fluorescence signal value of each scanning point under fixed frequency can be used to characterize the magnetic field strength of each scanning point.

[0059] For areas containing defects, such as confining the defect to a rectangular or circular region, wide-field imaging can be used to obtain higher resolution and more detailed detection. For larger samples where a single field of view cannot cover the entire sample surface, scanning the upper surface of the sample with a probe and then performing wide-field imaging on the defect area can accelerate the efficiency of defect detection.

[0060] In wide-field imaging, excitation light is transmitted from wide-field branch 2 to probe 7, and the fluorescence generated by probe 7 is collected and imaged by wide-field imaging optical path 30. This method of ODMR measurement to obtain the magnetic field intensity distribution refers to performing fluorescence imaging at each frequency point when using the microwave frequency sweep method for ODMR, obtaining a grayscale image, acquiring imaging data, plotting the ODMR spectrum of the grayscale value of each pixel as a function of microwave frequency, and then calculating the magnetic field intensity of each pixel from the resonance frequency on the spectrum. These are then combined into a single image to form the magnetic field intensity distribution. This method provides higher resolution information on defect distribution, such as location information and defect continuity, allowing for more accurate defect identification and analysis.

[0061] Of course, the fixed-frequency method can also be used to perform ODMR measurements. Within the half-width range of the fixed-frequency point, different magnetic field strengths can correspond to different fluorescence intensities, which are reflected in the image as gray values. The distribution of gray values ​​at the fixed-frequency point can be used to characterize the distribution of magnetic field strength.

[0062] In this embodiment, the integrated testing system, when including an illumination module, can also perform illumination testing during non-destructive testing.

[0063] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. An integrated detection system based on solid-state spin centers, characterized in that, The detection system includes: an excitation light module, a wide-field branch, a confocal branch, a first beam splitter, a first dichroic filter, an objective lens, a probe containing a solid-state spin center, a first filter, a guiding element, a first photoelectric detection optical path, a second photoelectric detection optical path, a wide-field imaging optical path, a differential module, and a microwave module. Excitation light module, used for switchable delivery of excitation light to wide-field branch and confocal branch; The wide-field branch is used to receive and process the excitation light to obtain a beam that satisfies wide-field imaging. The confocal branch is used to receive the excitation light and process it to obtain a beam that satisfies the requirements of confocal detection. The first beam splitter receives two excitation beams output from the wide-field branch and the confocal branch respectively, and splits a portion of each excitation beam to the first dichroic filter. The first dichroic filter guides the excitation light to the objective lens, which transmits it to the probe. The fluorescence generated by the probe is then transmitted through the objective lens, guided by the first dichroic filter, and transmitted through the first filter to the guiding element. When the excitation light is received in the confocal branch, the fluorescence is guided to the first photodetector optical path and collected and converted into the first electrical signal. Alternatively, when the excitation light is received in the wide-field branch, the fluorescence is guided to the wide-field imaging optical path and collected for imaging. The second photoelectric detection optical path receives another portion of the light from the confocal branch, which is split off by the first beam splitter, and converts it into a second electrical signal. The differential module is connected to the first photoelectric detection optical path and the second photoelectric detection optical path. It is used to receive the first electrical signal and the second electrical signal, and to perform differential processing on them to obtain a differential electrical signal. The microwave module is used to radiate microwaves to the probe.

2. The integrated detection system based on solid-state spin centers according to claim 1, characterized in that: The excitation light module includes two excitation light sources for delivering excitation light to the wide-field branch and the confocal branch in a one-to-one correspondence; or the excitation light module includes one excitation light source, a first reflector, and a second reflector; the first reflector is a rotatable reflector, when the first reflector is rotated to a first state, the excitation light output by the excitation light source is reflected by the first reflector and transmitted to the second reflector, and then reflected to one of the branches; when the first reflector is rotated to a second state, the excitation light output by the excitation light source is transmitted in a straight line to the other branch.

3. The integrated detection system based on solid-state spin centers according to claim 1, characterized in that: When the excitation light output by the excitation light module to the wide-field branch is laser light, the wide-field branch includes a first condenser lens; when the excitation light output by the excitation light module to the wide-field branch is incoherent light, the wide-field branch includes one or more condenser lenses; when the excitation light output by the excitation light module to the confocal branch is laser light, the confocal branch includes two condenser lenses.

4. The integrated detection system based on solid-state spin centers according to claim 1, characterized in that: The guiding element is a fourth reflecting mirror, which is flip-up. When the fourth reflecting mirror is rotated to the first state, the light filtered by the first filter is transmitted to its reflecting surface and reflected to one of the first photoelectric detection optical path and the wide field imaging optical path. When the fourth reflecting mirror is rotated to the second state, the light filtered by the first filter is transmitted in a straight line to the other of the first photoelectric detection optical path and the wide field imaging optical path.

5. The integrated detection system based on solid-state spin centers according to claim 1, characterized in that: It also includes a bias magnetic field module for applying a bias magnetic field to the probe.

6. The integrated detection system based on solid-state spin centers according to claim 1, characterized in that: It also includes an excitation light adjustment module, which receives a first electrical signal and a differential signal, and adjusts the excitation light power transmitted to the second photoelectric detection optical path so that the ratio of the differential electrical signal to the first electrical signal is a preset value.

7. The integrated detection system based on solid-state spin centers according to claim 6, characterized in that: The excitation light adjustment module includes a control module, a driver, and a gradient filter or polarizer. The gradient filter or polarizer is located on the transmission optical path from the excitation light to the second photodetector optical path. The control module is used to collect differential electrical signals and a first electrical signal, and controls the driver to move the gradient filter or rotate the polarizer according to the differential electrical signals and the first electrical signal, thereby changing the power of the excitation light by changing the position of the excitation light passing through it. Alternatively, the excitation light adjustment module includes an electric aperture and a control module. The electric aperture is located on the transmission optical path from the excitation light to the second photodetector optical path, and the control module controls the aperture area of ​​the electric aperture that allows light to pass through according to the differential electrical signals and the first electrical signal, thereby changing the power of the excitation light passing through.

8. The integrated detection system based on solid-state spin centers according to any one of claims 1-7, characterized in that: It also includes an illumination module and a second beam splitter. The second beam splitter is located between the first dichroic filter and the first filter. The illumination light output by the illumination module illuminates the second beam splitter. A portion of the light split by the second beam splitter is transmitted to the first dichroic filter, and then, after being guided by the first dichroic filter and transmitted through the objective lens, it illuminates the object side of the objective lens. The illumination light reflected from the object side is then transmitted through the objective lens, guided by the first dichroic filter, split by the second beam splitter, and transmitted through the first filter before being guided by the guiding element into the wide-field imaging optical path for imaging.

9. The integrated detection system based on solid-state spin centers according to claim 8, characterized in that: The wavelength of the illumination light is different from the fluorescence generated by the probe. The guiding element is a second dichromatic filter, which is flip-up. When transmitting excitation light to the confocal branch and turning on the illumination, the second dichromatic filter is rotated to the first state. The fluorescence filtered by the first filter is reflected by the second dichromatic filter to the first photoelectric detection optical path, and the illumination light is transmitted through the second dichromatic filter to the wide-field imaging optical path. When transmitting excitation light to the wide-field branch, the second dichromatic filter is rotated to the second state. The fluorescence filtered by the first filter is transmitted in a straight line to the wide-field imaging optical path.

10. A non-destructive testing method based on solid-state spin centers, characterized in that, An integrated detection system based on a solid-state spin center as described in any one of claims 1-9 is provided, wherein the integrated system further includes a moving device, on which a stage is used to place the sample to be tested and to control the movement of the sample; and includes a data processing module connected to the differential module and the wide-field imaging optical path, for acquiring differential electrical signals and reading imaging data or images, and processing and analyzing the differential electrical signals and imaging data or images, and connected to the microwave module for controlling the microwave frequency radiated therefrom; the method includes: The sample to be tested is placed under the probe, and the sample surface is scanned point by point using the probe. At each scanning point, ODMR measurement is performed using confocal detection to obtain the magnetic field strength at each scanning point. The magnetic field strength distribution formed by the magnetic field strength of all scanning points is used to determine whether there are defects in the sample. If defects are found, the area where the defects are located is taken as the target area for further detection. ODMR measurement is then performed on the target area using wide-field imaging to obtain the magnetic field strength distribution of the target area, thereby obtaining the distribution information of the defects.

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