A magnetic detection system for diamond NV color centers and a magnetic detection system

Abstract

The utility model discloses a kind of diamond NV color center magnetic detection system excitation assembly and magnetic detection system. Excitation assembly includes object table made of non-magnetic material, first magnetic conducting member and second magnetic conducting member respectively connected in object table both sides, first exciter and second exciter respectively connected below first magnetic conducting member and second magnetic conducting member, and third magnetic conducting member connected below first exciter and second exciter. When the sample to be measured is placed in object table, its both sides are respectively contacted with first magnetic conducting member and second magnetic conducting member, so that third magnetic conducting member, first exciter, first magnetic conducting member, sample to be measured, second magnetic conducting member and second exciter jointly constitute complete magnetic circuit. The technical scheme of the utility model makes excitation structure be located below space of sample to be measured, avoids shielding the light path above diamond, simultaneously avoids the problem that the magnetization effect is poor existing with air as magnetic circuit, improves magnetization effect of sample to be measured, and then improves the detection sensitivity to tiny defect.

Description

Technical Field

[0001] This utility model relates to the field of quantum sensing technology, specifically to an excitation component and magnetic detection system for a diamond NV color center magnetic detection system. Background Technology

[0002] Magnetic detection technology based on diamond NV centers can be used to detect surface or near-surface defects in ferromagnetic metal parts. During detection, the sample is typically magnetized first using an excitation device. When a crack exists in the sample, a leakage magnetic field is generated at the defect location. The diamond NV center probe detects changes in this leakage magnetic field to determine the location and condition of the defect.

[0003] In existing diamond NV color center magnetic detection systems, the diamond probe and objective lens are typically positioned above the sample. The objective lens needs to focus the laser onto the diamond probe from above and collect the fluorescence signal generated by the diamond. Therefore, a large optical detection space is required above the sample. If a traditional C-shaped or U-shaped magnetization device is used, parts of its structure may be located above the sample, potentially obstructing the laser or fluorescence path, affecting fluorescence collection efficiency, and thus reducing the quality of the detection signal.

[0004] To avoid obstructing the optical path, existing methods use two permanent magnets placed on either side of the sample or one permanent magnet placed near the defect location to magnetize the sample. However, this method relies on air as the magnetic flux return path, resulting in high magnetic reluctance and poor magnetization. When the sample defect is small, the leakage magnetic signal generated at the defect is weak. If the magnetization is insufficient, the diamond NV color center probe will have difficulty detecting the leakage magnetic signal stably.

[0005] Therefore, it is necessary to design an excitation component suitable for the diamond NV color center magnetic detection system, so as to improve the magnetization effect of the sample under test without blocking the upper optical path, and ensure the stability of the magnetization state during the detection process. Utility Model Content

[0006] The purpose of this invention is to provide an excitation component and a magnetic detection system for a diamond NV color center magnetic detection system, so as to solve the technical problems of poor magnetization effect and insufficient sensitivity for small defect detection in the prior art that uses air as a magnetic circuit.

[0007] In a first aspect, this utility model provides an excitation component for a diamond NV color core magnetic detection system, comprising: A stage for placing the sample to be tested, and the stage is made of a non-magnetic material; The first magnetic conductive element and the second magnetic conductive element are respectively connected to the two sides of the stage; when the sample to be tested is placed on the stage, its two sides are in contact with the first magnetic conductive element and the second magnetic conductive element respectively. A first exciter and a second exciter, wherein the first exciter is connected below the first magnetic conductor and the second exciter is connected below the second magnetic conductor; The third magnetic conductor is connected below the first exciter and the second exciter, so as to form a complete magnetic circuit together with the first magnetic conductor, the second magnetic conductor and the sample to be tested.

[0008] In some embodiments, the first magnetic conductive element or the second magnetic conductive element further includes: A magnetic focusing part is disposed at the end of the first magnetic conductive element or the second magnetic conductive element near the stage, and the cross-sectional area of ​​the magnetic focusing part gradually decreases along the direction close to the stage.

[0009] In some embodiments, the first magnetic conductor includes: A first magnetic conductive part extends horizontally, with one end of the first magnetic conductive part connected to one side of the stage; the other end of the first magnetic conductive part extends downward to form a second magnetic conductive part extending vertically, with the end of the second magnetic conductive part connected to the first exciter.

[0010] In some embodiments, the first magnetic conductive element and the second magnetic conductive element are structurally mirror-symmetrical.

[0011] In some embodiments, at least a portion of the upper surface of the first magnetic conductive element, the upper surface of the stage, and at least a portion of the upper surface of the second magnetic conductive element together form a continuous and flat loading surface, such that when the sample to be tested is placed on the stage, its two sides are in contact with the first magnetic conductive element and the second magnetic conductive element, respectively.

[0012] In some embodiments, both the first exciter and the second exciter are permanent magnets or energized coils.

[0013] In some embodiments, the first exciter and the second exciter, one of which is a permanent magnet and the other is an energized coil.

[0014] In some embodiments, the first magnetic conductor and the second magnetic conductor are made of iron.

[0015] In some embodiments, it also includes: A mounting base is disposed below the third magnetic component, and the mounting base is made of a non-magnetic material, for mounting the excitation assembly to the top of an electric displacement device.

[0016] Secondly, this utility model also provides a magnetic detection system based on diamond NV color centers, comprising: The excitation assembly provided in any of the first aspects of this utility model has a sample to be tested placed on a stage in the excitation assembly, and the two sides of the sample to be tested are in contact with the first magnetic conductive element and the second magnetic conductive element, respectively. The sensing probe includes an elongated support and a diamond containing an NV color center disposed at the end, the diamond being suspended above the surface of the sample to be tested; An optical path module is disposed above the diamond and is used to emit excitation light to the diamond and collect fluorescence from the diamond.

[0017] Compared with the prior art, the beneficial effects of this utility model include at least the following: The excitation assembly of the diamond NV center magnetic detection system provided by this invention consists of a stage made of non-magnetic material, a first magnetic guide and a second magnetic guide connected to its two sides, and a first exciter and a second exciter connected below the stage. Finally, a third magnetic guide connects the two exciters at the bottom, forming a complete magnetic circuit. When the sample to be tested is placed on the stage and in contact with the magnetic guides on both sides, the sample itself becomes part of this closed magnetic circuit. Compared to existing technologies that simply place magnets on both sides of the sample and rely on high magnetic reluctance air to form a circuit, the technical solution of this invention significantly reduces the total magnetic reluctance of the magnetic circuit. This results in a substantial increase in the effective magnetic flux density passing through the sample under the same excitation source (permanent magnet or coil), enabling stronger and more uniform magnetization of the sample. Furthermore, this strengthens the leakage magnetic field generated at defects, making it easier for the diamond probe containing NV centers to detect, directly improving the system's sensitivity to detecting microcracks and defects. Furthermore, both the first and second exciters are located in the space below the stage, completely avoiding any intrusion into the optical detection space above the sample. The objective lens can perform laser focusing and fluorescence collection on the diamond probe from directly above without obstruction, ensuring efficient fluorescence collection and further guaranteeing detection quality. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of an excitation component for a diamond NV color core magnetic detection system according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of an excitation component for a diamond NV color core magnetic detection system according to an embodiment of the present invention.

[0019] Figure 3 This is a schematic diagram of the structure of a magnetic detection system based on diamond NV color centers provided in an embodiment of the present invention.

[0020] Explanation of reference numerals in the attached figures: 100-Stage; 210-First magnetic conductor; 220-Second magnetic conductor; 310-First exciter; 320-Second exciter; 400-Third magnetic conductor; 500-Mounting base; 10 - Sample to be tested; 20 - Diamond; 30 - Optical path module. Detailed Implementation

[0021] The present invention will be further described below with reference to specific embodiments.

[0022] To make the objectives, technical solutions, and advantages of this utility model clearer, the technical solutions of this utility model will be clearly and completely described below in conjunction with specific embodiments. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model.

[0023] A magnetic detection system based on a diamond NV center probe typically includes a stage, a sample to be tested, a sensing probe, and an optical path module. During operation, the sample is placed on the stage, and the diamond containing the NV center at the end of the sensing probe is positioned close to the sample surface. The optical path module, located above the diamond, emits excitation light to the diamond and collects fluorescence signals. Under the influence of an external magnetic field, the energy level structure of the diamond NV center changes, thereby altering its fluorescence properties. This fluorescence signal can then be used to detect the leakage magnetic field from defects on or near the surface of the sample.

[0024] In practical testing, to generate a sufficiently strong leakage magnetic field at cracks and defects in ferromagnetic metal parts, it is usually necessary to magnetize the sample before or during testing by applying a magnetic field. Existing magnetization schemes include two main approaches: one uses a C-shaped or U-shaped magnetizing device, but this tends to occupy the optical detection space between the diamond probe and the objective lens, obstructing the excitation light incident path and the fluorescence collection path. Another approach involves placing permanent magnets directly on both sides of the sample, or only on one side. This approach avoids the upper optical path, but because it uses air as the magnetic circuit, the high magnetic reluctance of air results in a small effective magnetic flux through the sample, leading to unsatisfactory magnetization. Especially when the defect size of the sample is small, the leakage magnetic signal at the defect is weak. If the sample is insufficiently magnetized, the diamond NV color center probe will struggle to stably detect the corresponding leakage magnetic field changes.

[0025] Based on this, the present invention provides an excitation component and a magnetic detection system for a diamond NV color center magnetic detection system. The excitation component comprises magnetically conductive elements on both sides of the stage, ensuring that the sample under test contacts these elements on both sides after placement. An exciter is positioned below the magnetically conductive elements, and the entire circuit is formed by connecting the components with another magnetically conductive element. This increases the effective magnetic flux through the sample under test without occupying any optical detection space above it, enhances the magnetization effect of the sample, and improves the stability of the magnetization state during the detection process.

[0026] Specifically, please refer to Figure 1 The excitation component for the diamond NV color center magnetic detection system provided in this embodiment includes a stage 100, a first magnetic conductor 210, a second magnetic conductor 220, a first exciter 310, a second exciter 320, and a third magnetic conductor 400.

[0027] The stage 100 is used to place the sample 10 to be tested, and the stage 100 is made of a non-magnetic material. The first magnetic element 210 and the second magnetic element 220 are respectively connected to both sides of the stage 100; when the sample 10 to be tested is placed on the stage 100, its two sides are in contact with the first magnetic element 210 and the second magnetic element 220, respectively. The first exciter 310 is connected below the first magnetic element 210, and the second exciter 320 is connected below the second magnetic element 220. The third magnetic element 400 is connected below the first exciter 310 and the second exciter 320, so that together with the first magnetic element 210, the second magnetic element 220, and the sample 10 to be tested, they form a complete magnetic circuit.

[0028] Specifically, the stage 100 can be used to support sheet-like, block-like, or strip-shaped samples 10 to be tested. The stage 100 is made of non-magnetic materials, such as plastics, ceramics, and non-magnetic composite materials, to prevent magnetic flux from passing through the stage 100. The first magnetic conductor 210 and the second magnetic conductor 220 are respectively disposed on the left and right sides of the stage 100. They can be fixedly connected to the stage 100 or positioned relative to the stage 100 by a support structure, as long as the samples 10 to be tested are placed on the stage 100 and their sides are in contact with the first magnetic conductor 210 and the second magnetic conductor 220 respectively. The first exciter 310 and the second exciter 320 are respectively located below the left and right magnetic conductors and are used to provide an excitation magnetic field for the magnetic circuit. The third magnetic conductor 400 is located further down and connects the first exciter 310 and the second exciter 320, so that the magnetic flux can return at the bottom.

[0029] In use, after the sample 10 to be tested is placed on the stage 100, its left and right sides are in contact with the first magnetic conductor 210 and the second magnetic conductor 220, respectively. The magnetic flux generated by the first exciter 310 or the second exciter 320 can enter the sample 10 to be tested through the first magnetic conductor 210 or the second magnetic conductor 220, and at the same time form a closed loop through the third magnetic conductor 400 below, so the sample 10 to be tested itself also becomes part of the magnetic loop.

[0030] In this embodiment, by placing the first magnetic conductive element 210 and the second magnetic conductive element 220 on both sides of the stage 100, and ensuring that the sides of the sample 10 to be tested are in contact with the first magnetic conductive element 210 and the second magnetic conductive element 220 respectively after placement, the sample 10 to be tested can be directly placed in the magnetic circuit. Compared with a structure where only the permanent magnet or coil is placed close to the sample and the magnetic flux is mainly closed through the air, this embodiment allows the magnetic flux to pass through the sample 10 to be tested more directly, thereby improving the magnetization degree of the sample 10 to be tested. In addition, by placing the first exciter 310 and the second exciter 320 below the first magnetic conductive element 210 and the second magnetic conductive element 220 respectively, and connecting them below the third magnetic conductive element 400, a more complete closed magnetic circuit can be formed. The magnetic flux forms a closed path through the magnetic conductive element and the sample 10 to be tested, with low magnetic resistance and less magnetic flux leakage, which is beneficial to increasing the effective magnetic flux passing through the sample 10 to be tested and improving the excitation efficiency. Furthermore, since the first magnetic conductive element 210 and the second magnetic conductive element 220 are mainly located on both sides of the sample 10 to be tested, while the first exciter 310, the second exciter 320 and the third magnetic conductive element 400 are mainly located below the sample 10 to be tested, the excitation assembly completely avoids the optical detection space above the sample 10 to be tested. This is beneficial for cooperating with the diamond NV color center probe and optical path module set above the sample 10 to be tested, reducing the obstruction of excitation light incident and fluorescence collection, and improving fluorescence collection efficiency.

[0031] In some embodiments, please refer to Figure 2 The first magnetic conductor 210 or the second magnetic conductor 220 further includes a magnetic focusing part. The magnetic focusing part is disposed at the end of the first magnetic conductor 210 or the second magnetic conductor 220 near the stage 100, and the cross-sectional area of ​​the magnetic focusing part gradually decreases along the direction near the stage 100 until it matches the cross-sectional dimensions of both sides of the stage 100.

[0032] Specifically, the magnetic focusing part can be formed at one end of the first magnetic conductor 210 near the stage 100, or at one end of the second magnetic conductor 220 near the stage 100. Preferably, both the first magnetic conductor 210 and the second magnetic conductor 220 are provided with magnetic focusing parts. The magnetic focusing part can be a wedge-shaped structure that gradually narrows as it extends horizontally, or a circular arc transition diameter-reducing structure. Its end dimension is adapted to the dimensions of the corresponding areas on both sides of the stage 100, so that when the sample 10 to be tested is placed on the stage 100, the magnetic focusing part can make corresponding contact with the side of the sample 10 to be tested in a smaller area.

[0033] The above embodiment, by providing a magnetic focusing part at one end of the first magnetically conductive element 210 and / or the second magnetically conductive element 220 near the stage 100, and by gradually decreasing the cross-sectional area of ​​the magnetic focusing part along the direction near the stage 100, enables the magnetic flux transmitted from the magnetically conductive element to the region of the sample 10 to be tested to be further focused near the sample 10. Since the local magnetic flux density increases when the same magnetic flux passes through a smaller cross-sectional area, the magnetic field line density near the contact areas on both sides of the sample 10 can be increased, thereby enhancing the magnetization intensity of the local area of ​​the sample 10.

[0034] In this embodiment, the first magnetic conductive member 210 includes a first magnetic conductive portion extending in a horizontal direction and a second magnetic conductive portion extending in a vertical direction. One end of the first magnetic conductive portion is connected to one side of the stage 100; the other end of the first magnetic conductive portion extends downward to form the second magnetic conductive portion, and the end of the second magnetic conductive portion is connected to the first exciter 310.

[0035] In this embodiment, by setting the first magnetic conductive element 210 to include a first magnetic conductive part extending in the horizontal direction and a second magnetic conductive part extending in the vertical direction, it is convenient to form a magnetic flux input / output position that contacts the sample 10 under test in the upper part, and it is also convenient to arrange the exciter in the lower area to avoid blocking the upper optical path.

[0036] In this embodiment, the first magnetic conductive element 210 and the second magnetic conductive element 220 are structurally mirror-symmetrical.

[0037] Specifically, the first magnetic conductive element 210 and the second magnetic conductive element 220 can be respectively disposed on the left and right sides of the stage 100, and the two are distributed in a mirror image about the central axis of the stage 100. Specifically, if the first magnetic conductive element 210 includes a first magnetic conductive portion extending in the horizontal direction and a second magnetic conductive portion extending in the vertical direction, then the second magnetic conductive element 220 also includes a corresponding first magnetic conductive portion extending in the horizontal direction and a second magnetic conductive portion extending in the vertical direction.

[0038] In this embodiment, by adopting a mirror-symmetric structure for the first magnetic conductive element 210 and the second magnetic conductive element 220, the magnetic conductive paths and spatial arrangements on both sides of the sample 10 under test are basically consistent. This helps to ensure that both sides of the sample 10 under test receive a more balanced magnetic effect, reducing the uneven magnetic field distribution caused by differences in the left and right structures.

[0039] In some embodiments, at least a portion of the upper surface of the first magnetic conductive element 210, the upper surface of the stage 100, and at least a portion of the upper surface of the second magnetic conductive element 220 together form a continuous and flat loading surface, such that when the sample to be tested 10 is placed on the stage 100, its two sides are in contact with the first magnetic conductive element 210 and the second magnetic conductive element 220, respectively.

[0040] Specifically, the stage 100 is located in the middle position, and the top of the first magnetic conductor 210 and the second magnetic conductor 220 near the stage 100 are at the same or approximately the same height as the upper surface of the stage 100. The three together form a continuous and flat bearing surface on the upper part. The sample 10 to be tested, such as a sheet metal specimen, a strip workpiece, or other samples with a relatively flat bottom surface, can be placed stably on the bearing surface, and under its own weight, its two sides will contact the first magnetic conductor 210 and the second magnetic conductor 220 respectively.

[0041] In this embodiment, by having at least a portion of the upper surface of the first magnetic conductive element 210, the upper surface of the stage 100, and at least a portion of the upper surface of the second magnetic conductive element 220 together form a continuous and flat loading surface, the sample to be tested 10 can maintain good contact with the first magnetic conductive element 210 and the second magnetic conductive element 220 when placed.

[0042] In this embodiment, both the first exciter 310 and the second exciter 320 are permanent magnets or energized coils.

[0043] Specifically, the first exciter 310 and the second exciter 320 can both employ permanent magnets or both employ energized coils. When both are permanent magnets, they can be respectively positioned below the first magnetic conductor 210 and the second magnetic conductor 220, providing excitation for the entire magnetic circuit through the inherent magnetic field of the permanent magnets. When both are energized coils, coils can be wound around the corresponding iron core or magnetic core, generating a controllable magnetic field through external power supply.

[0044] When both the first exciter 310 and the second exciter 320 use permanent magnets, a stable magnetic field can be provided for the magnetic circuit without the need for continuous power supply. This simplifies the system power supply structure and reduces energy consumption and control complexity during use. Simultaneously, the permanent magnet's output magnetic field is relatively constant, which helps maintain the stable magnetization state of the sample 10 under test.

[0045] When both the first exciter 310 and the second exciter 320 use energized coils, the excitation intensity can be adjusted by adjusting the input current to meet the magnetization requirements of different test samples 10.

[0046] In other embodiments, the first exciter 310 and the second exciter 320, one employs a permanent magnet and the other employs an energized coil.

[0047] Specifically, the first exciter 310 can be a permanent magnet and the second exciter 320 can be an energized coil; or the first exciter 310 can be an energized coil and the second exciter 320 can be a permanent magnet.

[0048] In this embodiment, the first magnetic conductive element 210 and the second magnetic conductive element 220 are made of iron.

[0049] Specifically, the first magnetic conductive element 210 and the second magnetic conductive element 220 can be made of pure iron, low carbon steel, electrical pure iron or other iron-based materials with good magnetic conductivity. The magnetic flux can be transmitted smoothly in the magnetic conductive element and together with the sample 10 to be tested, they form a low magnetic resistance magnetic circuit.

[0050] In this embodiment, by setting the first magnetic conductive element 210 and the second magnetic conductive element 220 as ferromagnetic materials (such as pure iron or low-carbon steel), their good magnetic permeability can reduce the magnetic resistance of the magnetic conductive element and improve the transmission efficiency of magnetic flux in the magnetic conductive paths on both sides. This is beneficial for more effectively coupling the magnetic field generated by the first exciter 310 and the second exciter 320 to the region of the sample 10 under test, reducing the loss of magnetic flux during transmission within the magnetic conductive element. At the same time, iron magnetic conductive elements have the advantages of readily available materials, convenient processing, and high mechanical strength, which is also conducive to the engineering manufacturing and long-term stability of the excitation assembly.

[0051] In this embodiment, the excitation assembly further includes a mounting base 500. The mounting base 500 is disposed below the third magnetic conductive element 400 (which is also a ferromagnetic material), and the mounting base 500 is made of a non-magnetic material, for mounting the excitation assembly to the top of an electric displacement device.

[0052] Specifically, the mounting base 500 can be located below the lower surface of the third magnetic conductor 400 and fixed to the third magnetic conductor 400 by screws or other mechanical connections. The lower part of the mounting base 500 can be provided with a connection hole positioning structure adapted to the top of the electric displacement device, so as to install the entire excitation assembly on the top of the electric displacement device. The mounting base 500 is made of non-magnetic material, which can reduce the possibility of the base part participating in the magnetic flux loop, avoid magnetic flux shunting from the base, and thus help maintain the integrity of the original main magnetic loop and the stability of the magnetic field.

[0053] In this embodiment, by providing a mounting base 500 below the third magnetic conductor 400 and using the mounting base 500 to mount the excitation assembly to the top of the electric displacement device, the entire excitation assembly can have the ability to move as a whole and adjust its position.

[0054] Based on the same inventive concept, this embodiment also provides a magnetic detection system based on diamond NV color centers. Please refer to [link to relevant documentation]. Figure 3 The magnetic detection system includes the excitation component, sensing probe, and optical path module 30 as described in any of the above embodiments.

[0055] The excitation assembly includes a stage 100 for placing the sample 10, with both sides of the sample 10 in contact with the first magnetic conductor 210 and the second magnetic conductor 220, respectively. The sensing probe includes an elongated support and a diamond 20 containing NV color centers at its end, suspended above the surface of the sample 10. An optical path module 30 is positioned above the diamond 20 to emit excitation light towards it and collect fluorescence from it.

[0056] In practical use, the sample 10 to be tested is first placed on the stage 100 of the excitation assembly, with its two sides in contact with the first magnetic conductive element 210 and the second magnetic conductive element 220. Then, the first exciter 310 and the second exciter 320 generate an excitation magnetic field, forming a complete magnetic circuit with the first magnetic conductive element 210, the second magnetic conductive element 220, and the third magnetic conductive element 400, thus magnetizing the sample 10. When the sample 10 has cracks or other defects, a leakage magnetic field is generated at the defect location. The diamond 20 at the end of the sensing probe approaches the surface of the sample 10 and generates a detectable fluorescent signal under the excitation light provided by the optical path module 30. By analyzing the changes in this fluorescent signal, information related to the leakage magnetic field of the sample 10 can be obtained.

[0057] In this embodiment, by applying the above-mentioned excitation component to a magnetic detection system based on diamond NV color centers, on the one hand, the excitation component can form a more complete magnetic circuit, improve the magnetization degree of the sample 10 under test, and enhance the leakage magnetic signal at the defect; on the other hand, since the excitation structure is completely distributed in the space below the sample 10 under test, it can avoid occupying the optical detection space above the sample 10 under test, and there is no obstruction to the excitation light irradiation and fluorescence collection path.

[0058] It should be noted that in the above embodiments, the specific shape, size, and material of the first, second, and third magnetic conductive elements, the specific type and installation method of the first and second exciters, and the connection structure between the stage and the magnetic conductive elements can all be adjusted according to the actual size, shape, and magnetic detection requirements of the sample to be tested. As long as the sample to be tested can be placed on the stage, with both sides in contact with the first and second magnetic conductive elements respectively, and together with the third magnetic conductive element and the exciter, forming a complete magnetic circuit, thereby improving the magnetization effect of the sample to be tested without obstructing the light path above the sample, it should be considered to fall within the protection scope of this utility model.

[0059] It should be noted that the above description is only a preferred embodiment of the present utility model and is not intended to limit the scope of protection of the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the scope of protection of the present utility model.

Claims

1. An excitation component for a diamond NV color core magnetic detection system, characterized in that, include: A stage for placing the sample to be tested, and the stage is made of a non-magnetic material; The first magnetic conductor and the second magnetic conductor are respectively connected to both sides of the stage; When the sample to be tested is placed on the stage, its two sides are in contact with the first magnetic conductive element and the second magnetic conductive element, respectively. A first exciter and a second exciter, wherein the first exciter is connected below the first magnetic conductor and the second exciter is connected below the second magnetic conductor; The third magnetic conductor is connected below the first exciter and the second exciter, so as to form a complete magnetic circuit together with the first magnetic conductor, the second magnetic conductor and the sample to be tested.

2. The excitation assembly as described in claim 1, characterized in that, The first magnetic conductive element or the second magnetic conductive element further includes: A magnetic focusing part is disposed at the end of the first magnetic conductive element or the second magnetic conductive element near the stage, and the cross-sectional area of ​​the magnetic focusing part gradually decreases along the direction close to the stage.

3. The excitation assembly as described in claim 1, characterized in that, The first magnetic conductive element includes: A first magnetic conductive part extends horizontally, with one end of the first magnetic conductive part connected to one side of the stage; the other end of the first magnetic conductive part extends downward to form a second magnetic conductive part extending vertically, with the end of the second magnetic conductive part connected to the first exciter.

4. The excitation assembly as described in claim 3, characterized in that, The first magnetic conductive element and the second magnetic conductive element have a mirror-symmetric structure.

5. The excitation assembly as described in claim 1, characterized in that, At least a portion of the upper surface of the first magnetic conductive element, the upper surface of the stage, and at least a portion of the upper surface of the second magnetic conductive element together form a continuous and flat loading surface, such that when the sample to be tested is placed on the stage, its two sides are in contact with the first magnetic conductive element and the second magnetic conductive element, respectively.

6. The excitation assembly as described in claim 1, characterized in that, Both the first exciter and the second exciter use permanent magnets or energized coils.

7. The excitation assembly as described in claim 1, characterized in that, The first exciter and the second exciter, one of which uses a permanent magnet and the other uses an energized coil.

8. The excitation assembly as described in claim 1, characterized in that, The first magnetic conductive element and the second magnetic conductive element are made of ferromagnetic material.

9. The excitation assembly as described in claim 1, characterized in that, Also includes: A mounting base is disposed below the third magnetic component, and the mounting base is made of a non-magnetic material, for mounting the excitation assembly to the top of an electric displacement device.

10. A magnetic detection system based on diamond NV color centers, characterized in that, include: The excitation assembly as described in any one of claims 1 to 9, wherein a sample to be tested is placed on the stage of the excitation assembly, and the two sides of the sample to be tested are in contact with the first magnetic conductive element and the second magnetic conductive element, respectively; The sensing probe includes an elongated support and a diamond containing an NV color center disposed at the end, the diamond being suspended above the surface of the sample to be tested; An optical path module is disposed above the diamond and is used to emit excitation light to the diamond and collect fluorescence from the diamond.

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