Quantum sensing unit, wide-field detection probe and defect imaging system

Abstract

The invention discloses a quantum sensing unit, a wide-field detection probe and a defect imaging system.The quantum sensing unit comprises a transparent substrate, an incidence port, a light reflecting medium and a light filtering medium, the quantum sensing unit has a larger detection area compared with an existing diamond NV color center particle, imaging coverage detection of a defect area can be achieved, and the detection accuracy is improved. Due to the design of the internal reflection structure of the sensing unit, on one hand, the color center excitation process based on the laser beam is more sufficient and efficient, and on the other hand, due to the fact that laser does not need to be expanded, the light path can be more stable and reliable when the laser beam is used for color center excitation. The wide-field detection probe uses a combination of a wide-field camera, an objective lens and a quantum sensing unit which are adaptive to each other, so that fluorescent light in extremely small pixels can be distinguished and detected, and the detection resolution can be improved.

Description

Technical Field

[0001] The present invention relates to the field of quantum sensing technology, and in particular to a quantum sensing unit, a wide-field detection probe and a defect imaging system. Background Art

[0002] NV (nitrogen-vacancy) color centers in diamond are a common diamond defect, which is formed by a nitrogen atom replacing a carbon atom in the diamond lattice, and there is a vacancy (i.e., a missing carbon atom) in the adjacent lattice. This structure causes changes in the surrounding electronic state, which changes the absorption and emission characteristics of diamond in the visible spectrum, producing specific colors. It is common to use 532 wavelength green excitation light to excite the NV color center, and correspondingly, the NV color center will produce red feedback fluorescence; and changes in some physical fields (such as magnetic fields, temperature, etc.) will cause specific changes in the red fluorescence it produces. Based on these specific changes, sensing measurements of specific physical fields can be achieved.

[0003] For example, a Chinese invention patent with authorization announcement number CN117705932B proposes a quantum nondestructive sensor and a rail surface defect detection machine, which utilizes an optical fiber-diamond NV color center probe to perform nondestructive detection of surface defects of ferromagnetic materials. It can accurately detect the leakage magnetic field on a single path. However, at present, the volume of diamonds containing NV color centers used in sensing detection is generally at the micron level, and the measurement coverage area is small, and the overall information of the defective area cannot be quickly obtained. In order to improve the rapid and sufficient detection of defective areas, the present invention proposes a corresponding solution. Summary of the invention

[0004] The present invention proposes a quantum sensing unit, a wide-field detection probe and a defect imaging system to solve the problems existing in the prior art.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A quantum sensing unit, comprising:

[0007] A transparent substrate, comprising a first surface, a second surface and a substrate peripheral side surface, which contains NV color centers that generate feedback fluorescence under the irradiation of excitation light;

[0008] An incident port is arranged on the side surface of the substrate, and the excitation light enters from the incident port;

[0009] A reflective medium, which is arranged on the peripheral side surface of the base except the incident port and the first surface;

[0010] The filter medium is arranged on the second surface and is used for filtering out the feedback fluorescence.

[0011] Preferably, the transparent substrate as a whole is a diamond block with NV color centers evenly distributed inside, or the transparent substrate is composed of diamond particles containing ensemble NV color centers evenly distributed inside.

[0012] Preferably, the incident port is provided with an anti-reflection film.

[0013] Preferably, the reflective medium is disposed on the transparent substrate in a coating state.

[0014] Preferably, the filter medium is also used to reflect the excitation light.

[0015] Preferably, it further comprises a filter plate arranged on the filter medium, wherein the filter plate is used to filter out stray light.

[0016] On the other hand, the present invention also provides a wide-field detection probe, which uses the quantum sensing unit as described in any of the previous items and includes an objective lens adapted to the transparent substrate, which is used to magnify the second surface of the transparent substrate; and includes a wide-field camera adapted to the objective lens, which is used to photograph the second surface magnified by the objective lens.

[0017] Preferably, it further comprises a bottom plate for mounting the quantum sensing unit, the bottom plate is provided with a through groove corresponding to the first surface, and a fiber optic coupler or a light source is arranged on the bottom plate at a position corresponding to the incident port.

[0018] Preferably, the device further comprises a microwave radiator, wherein the microwave radiator is used to radiate a microwave field toward the transparent substrate.

[0019] On the other hand, the present invention further provides a defect imaging system for defect imaging detection of ferromagnetic objects, which uses the wide-field detection probe as described in any of the preceding items.

[0020] The beneficial effects of the present invention are:

[0021] (1) Compared with the existing diamond NV color center particles, the quantum sensing unit in the present invention has a larger detection area and a larger measurement coverage area, which can realize imaging coverage detection of the defect area and quickly obtain the overall information of the defect area. In addition, the internal reflection structure design of the sensing unit makes the laser beam-based color center excitation process more sufficient and efficient. On the other hand, since there is no need to expand the laser beam, the use of laser beams for color center excitation makes the optical path more stable and reliable.

[0022] (2) The wide-field detection probe in the present invention uses a wide-field camera, an objective lens and a quantum sensor unit adapted to detect fluorescence in extremely small pixels, thereby improving the detection resolution. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for describing the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0024] Figure 1 This is a schematic diagram of the structure of the quantum sensing unit in Example 1;

[0025] Figure 2 This is an overall schematic diagram of the wide-field detection probe in Example 2;

[0026] Figure 3 is a schematic structural diagram of a base plate containing an optical fiber coupler in Example 2;

[0027] Figure 4 is a schematic structural diagram of a base plate containing a light source in Example 2;

[0028] Figure 5 Schematic diagram of the structure of the defect imaging system in Example 3. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] Embodiment 1:

[0031] See attached Figure 1 This embodiment provides a quantum sensing unit, including a transparent substrate 1, an incident port 2, a reflective medium 3 and a filter medium 4.

[0032] Among them, the transparent substrate 1 includes a first surface, a second surface and a peripheral side surface of the substrate, which contains NV color centers that generate feedback fluorescence under the irradiation of excitation light; in some embodiments, the transparent substrate 1 can be a diamond block with NV color centers evenly distributed inside, but in this option, based on the difficulty and cost of manufacturing large-sized diamond blocks, the overall size of the transparent substrate 1 is difficult to increase, and it is difficult to obtain a larger-size detection imaging effect. Taking this problem into consideration, in another scheme, the transparent substrate 1 is designed to have diamond particles evenly distributed inside containing ensemble NV color centers. In this scheme, the transparent substrate 1 is a non-diamond transparent material, such as epoxy resin, and the size of the diamond particles is nanometer-level; in some schemes, the transparent substrate 1 is a rectangular thin block, the first surface is the top surface, and the second surface is the bottom surface.

[0033] Among them, the incident port 2 is arranged on the side surface of the substrate, and the excitation light enters from the incident port 2; taking the transparent substrate 1 as a rectangular thin block as an example, the incident port 2 is arranged on its side, considering that part of the excitation light and feedback fluorescence will leak from this position and cause waste, in order to reduce waste, the area of ​​the incident port 2 should be minimized while ensuring that the excitation light can fully enter; in addition, in order to avoid the waste of light reflection generated when the excitation light enters the incident port 2, in some preferred designs, a layer of anti-reflection film is also designed on the surface of the incident port 2.

[0034] Among them, the reflective medium 3 is arranged on the surrounding side surfaces of the substrate except the incident port 2 and the first surface; taking the transparent substrate 1 as a rectangular thin block as an example, the reflective medium 3 is arranged on the bottom surface of the rectangular thin block and all side parts except the incident port 2; regarding the reflective medium 3, the purpose in this example is mainly to enable the excitation light to be reflected multiple times inside the transparent substrate 1 to improve the efficiency of exciting the NV color center to generate feedback fluorescence. In a preferred scheme, the reflective medium 3 is designed in the form of a coating, and its material can be gold or silver, etc.

[0035] Among them, the filter medium 4 is arranged on the second surface to filter out the feedback fluorescence; taking the transparent substrate 1 as a rectangular thin block as an example, the generated feedback fluorescence can only be collected and obtained from the second surface (top surface), and the excitation light is also transmitted with the feedback fluorescence. In order to obtain high-purity feedback fluorescence, the filter medium 4 is designed on the second surface to only allow the feedback fluorescence to pass through it; in addition, considering that the excitation light will escape from the second surface and cause waste, in order to avoid this part of waste, in some design schemes, the filter medium 4 is also used to reflect the excitation light. For this, different from the indiscriminate light reflection of the aforementioned reflective medium, it is required here that the filter medium 4 can transmit the feedback fluorescence and reflect the excitation light. A structure similar to a two-color filter can be selected, which can achieve the effect of transmitting red light and reflecting green light; in addition, considering that stray light may still exist after filtering by the filter medium 4, a further scheme also includes a filter 5 arranged on the filter medium, and the filter 5 is used to filter out stray light.

[0036] Embodiment 2:

[0037] This embodiment designs a wide-field detection probe based on the quantum sensing unit proposed in Embodiment 1, see Attachment 1. Figure 2 In addition to the aforementioned quantum sensing probe, the system is also provided with an objective lens 6 and a wide-field camera 7.

[0038] Among them, the objective lens 6 is adapted to the transparent substrate 1, and is used to magnify the second surface of the transparent substrate. In an exemplary solution, the objective lens 6 is arranged at a fixed height above the transparent substrate 1, and this height enables the second surface to be effectively focused and magnified by the objective lens 6, so that the wide-field camera 7 adapted to the objective lens 6 can clearly photograph the second surface magnified by the objective lens 6. In a preferred solution, the wide-field camera 7 uses CCD or CMOS, and the wide-field camera 7 can be directly connected to the objective lens 6 and installed as a whole.

[0039] In some preferred embodiments, as shown in the attached Figure 2-4 As shown, it also includes a bottom plate 8 for installing the quantum sensing unit, and the bottom plate 8 is provided with a through groove 81 corresponding to the first surface of the transparent substrate 1. When in use, the transparent substrate 1 is installed in the through groove 81, and the first surface is facing the object to be detected. In addition, in order to achieve the height fixation of the objective lens 6 and the transparent substrate 1, the bottom plate 8 and the objective lens 6 can be connected by a connecting frame 11. The length of the connecting frame 11 is set and can meet the detection requirements.

[0040] In this embodiment, based on the design of the incident port 2, the incident area of ​​the excitation light is limited. Based on the design of the bottom plate 8, in one solution, see the attached Figure 3 , a fiber coupler 101 is arranged on the bottom plate 8 at a position corresponding to the incident port 2, and the fiber coupler 101 is connected to the external optical fiber for transmitting the excitation light, and the excitation light enters the incident port 2 from the fiber coupler 101; in addition, considering the problem of optical fiber transmission loss, in another solution, see the attached Figure 4 A light source 102 (replacing the optical fiber coupler 101) is arranged on the bottom plate 8 at a position corresponding to the incident port 2. By supplying power, the light source 102 directly outputs excitation light to the incident port 2. In this design, the bottom plate 8 can be designed as a circuit board structure, and the light source 102 is installed and connected through electrodes and conductive structures.

[0041] In addition, regarding the measurement application of NV color centers, the measurement method based on ODMR technology is popular. This method also uses microwaves to modulate NV color centers. Therefore, in some schemes, a microwave radiator 9 is also included. The microwave radiator 9 is used to radiate a microwave field to the transparent substrate 1. The structure design of the microwave radiator 9 is diverse, and it can be a copper coil or a microstrip antenna. Figure 3 In the scheme shown in FIG. 4 , a microwave radiator 9 is proposed which is designed on a base plate 8 by etching, and the etching material is copper.

[0042] Embodiment 3:

[0043] This example proposes a defect imaging system for defect imaging detection of ferromagnetic objects, which uses the wide-field detection probe described in Example 2.

[0044] In the exemplary scheme, for ease of understanding, the following Figure 5 For example, the wide-field detection probe in the system is a probe design that uses an optical fiber coupler 101 and a microwave radiator 9. Correspondingly, the system is also provided with a laser unit 11, a microwave unit 12 and a processor 13 (host). The excitation light output by the laser unit 11 is transmitted to the optical fiber coupler 101 through the optical fiber, and then enters the transparent substrate 1 to excite the NV color center. Synchronously, the microwave signal output by the microwave unit 12 enters the microwave radiator 9 through the radio frequency transmission line, and then forms a microwave field that acts on the NV color center. The transparent substrate 1 senses the ferromagnetic object to be tested on the bottom side (at this time, it should be noted that the magnetizing accessories should be used to magnetize it first to generate a leakage magnetic field that characterizes the defects), and generates wide-field feedback fluorescence on the second side. The wide-field camera 7 captures the fluorescence data of the second side through the objective lens 6 and transmits it to the processor 13 for imaging processing.

[0045] Of course, the above system composition design is only one type of defect imaging system. For example, if the wide-field detection probe is a probe design using a light source 102 and a microwave radiator 9, then correspondingly, the laser unit 11 in the above example is replaced by a light source power supply module.

[0046] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0047] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to only specific implementation methods. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A quantum sensing unit, characterized in that: Include: A transparent substrate, comprising a first surface, a second surface and a substrate peripheral side surface, containing NV color centers that generate feedback fluorescence under the irradiation of excitation light; An incident port is arranged on the side surface of the substrate, and the excitation light enters from the incident port; A reflective medium, which is arranged on the peripheral side surface of the base except the incident port and the first surface; The filter medium is arranged on the second surface and is used for filtering out the feedback fluorescence.

2. The quantum sensing unit according to claim 1, characterized in that: The transparent substrate as a whole is a diamond block with NV color centers evenly distributed inside, or the transparent substrate is evenly distributed with diamond particles containing ensemble NV color centers.

3. The quantum sensing unit according to claim 1, characterized in that The incident port is provided with an anti-reflection film.

4. The quantum sensing unit according to claim 1, characterized in that The reflective medium is arranged on the transparent substrate in a coating state.

5. The quantum sensing unit according to claim 1, characterized in that: The filter medium is also used to reflect the excitation light.

6. The quantum sensing unit according to claim 1, characterized in that The invention also comprises a filter plate arranged on the filter medium, and the filter plate is used for filtering out stray light.

7. A wide-field detection probe, applying the quantum sensing unit as described in any one of claims 1 to 6, and comprising an objective lens adapted to the transparent substrate, which is used to magnify the second surface of the transparent substrate; and comprising a wide-field camera adapted to the objective lens, which is used to photograph the second surface magnified by the objective lens.

8. The wide field detection probe according to claim 7, characterized in that: It also comprises a bottom plate for installing the quantum sensing unit, the bottom plate is provided with a through groove corresponding to the first surface, and a fiber coupler or a light source is arranged on the bottom plate at a position corresponding to the incident port.

9. The wide field detection probe according to claim 7 or 8, characterized in that: The invention also comprises a microwave radiator, which is used for radiating a microwave field toward the transparent substrate.

10. A defect imaging system for defect imaging detection of ferromagnetic objects, characterized in that: A wide-field detection probe as described in any one of claims 7 to 9 is used.

Images