Optical fiber probe based on diamond nv color center and magnetic scanning platform
By setting a receiving hole on the fiber optic probe and using a local melting locking structure to fix the diamond particles, the problem of probe damage and failure caused by optical adhesive bonding is solved, achieving efficient and stable fluorescence signal collection and extending probe life.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- ANHUI GUOSHENG QUANTUM TECH CO LTD
- Filing Date
- 2026-06-11
- Publication Date
- 2026-07-24
AI Technical Summary
Existing diamond particle fiber optic probes use optical adhesive bonding, which leads to poor resistance to laser damage, easy failure, and reduced fluorescence collection efficiency.
The fully mechanical, adhesive-free fixing method, which uses a receiving hole and local melting edge locking, physically locks the diamond particles by setting a receiving hole at the end of the optical fiber and using the locally melted optical fiber material to form an edge locking structure, thus avoiding the ablation of optical adhesive and loss of adhesion.
This technology enables long-term stable operation of the probe, ensuring high and stable fluorescence collection efficiency, improving the probe's vibration and shock resistance, extending its service life, and reducing maintenance costs.
Smart Images
Figure CN224553478U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the fields of precision measurement and fiber optic sensing technology, and more specifically, to a fiber optic probe and magnetic scanning platform based on diamond NV color centers. Background Technology
[0002] Magnetic imaging technology based on diamond particles is currently a research hotspot for high-sensitivity, high-spatial-resolution magnetic field sensing. Among them, the scanning probe measurement scheme constructs a sensing probe by fixing micron-sized diamond particles to the end of an optical fiber. Combined with optical path, microwave and other modules, it can perform point-by-point scanning magnetic imaging of the sample surface, and is widely used in fields such as metal surface crack detection and chip defect analysis.
[0003] In existing technologies, optical adhesives (such as UV adhesives) are commonly used to fix diamond particles to the ends of optical fibers. However, in practical applications, high-power lasers are often required to excite NV color center fluorescence in order to achieve high signal-to-noise ratio measurements. Under prolonged exposure to high-power lasers, the optical adhesive undergoes photothermal degradation, gradually turning black, carbonizing, and charring, leading to two serious problems: First, the carbonized layer severely hinders the collection efficiency of the fluorescence signal, reducing probe sensitivity; second, the adhesive bonding force is lost, causing the diamond particles to easily detach, resulting in probe failure. Therefore, existing adhesive bonding methods severely limit the usable laser power and long-term operational stability of the probe. Utility Model Content
[0004] This application provides a fiber optic probe and magnetic scanning platform based on diamond NV centers, which can solve the technical problems of poor resistance to laser damage, easy failure, and reduced fluorescence collection efficiency caused by the use of optical adhesive to bond existing diamond particle fiber optic probes.
[0005] The solution presented in this application is implemented through the following steps.
[0006] In a first aspect, an example of this application discloses an optical fiber probe based on diamond NV centers, comprising an optical fiber and diamond particles. A receiving hole is provided on the end face of the optical fiber, and the diamond particles are embedded in the receiving hole, wherein the aperture of the receiving hole is larger than the particle size of the diamond particles. A locking structure formed by partially fused optical fiber material is provided on the edge of the receiving hole or the sidewall of the receiving hole corresponding to the position of the diamond particles, and the locking structure physically locks the diamond particles in the receiving hole.
[0007] This application employs a fully mechanical, adhesive-free fixation method using a receiving hole and localized fusion-locking edge, avoiding the ablation, carbonization, and loss of adhesion of optical adhesive under high-power lasers, ensuring long-term stable operation of the probe. Furthermore, the locking structure is homogeneous with the fiber body, resulting in high fusion bonding strength, preventing diamond particles from easily detaching, and providing excellent vibration and impact resistance. Simultaneously, the absence of a carbonized adhesive layer obstructing the light path keeps the fiber end face and diamond particle surface clean, ensuring that signal collection efficiency does not decay over time and guaranteeing high and stable fluorescence collection efficiency. Moreover, the diamond particles, positioned at the fiber end face, can directly contact the sample under test, meeting resolution and accuracy requirements.
[0008] As described above, in the fiber optic probe based on diamond NV color centers, optionally, the fiber includes a solid silica fiber, and the receiving aperture includes a blind aperture formed on the end face of the solid silica fiber.
[0009] Solid quartz optical fiber has high light guiding efficiency and is suitable as a general probe carrier. Blind holes are formed on the optical fiber, which has a simple structure, mature processing technology, and is easy to achieve high-precision positioning. Furthermore, physical support is provided through the bottom of the blind hole to prevent excessive embedding of diamond particles.
[0010] As described above, in the fiber optic probe based on diamond NV color centers, optionally, the depth of the receiving hole is smaller than the particle size of the diamond particle, so that a portion of the diamond particle protrudes from the end face of the solid-core quartz fiber.
[0011] The prominent diamond particles can get infinitely close to the surface of the sample to be tested (the spacing can be less than 5μm), enabling near-field measurement, greatly improving spatial resolution and signal strength, and avoiding direct contact between the fiber end face and the sample, thus protecting the fiber.
[0012] As described above, in the diamond NV color center-based fiber optic probe, optionally, the fiber includes a hollow fiber or a capillary, and the receiving aperture includes the central hole of the hollow fiber or capillary.
[0013] Using hollow optical fibers or capillaries with their own central holes eliminates the need to process blind holes on the fiber end face, significantly simplifying the manufacturing process, reducing costs, and facilitating mass production and quality control using existing standard hollow optical fibers or capillaries.
[0014] As described above, in the fiber optic probe based on diamond NV color centers, optionally, the hollow fiber or capillary has a cut surface on the side of the diamond particle away from the locking structure, so that a section of the tube including the diamond particle forms the probe.
[0015] By cutting the probe, the overall size of the probe is greatly reduced, making it easier to integrate into a miniaturized magnetic scanning platform. This shortens the optical path length, reduces optical signal transmission loss, and the cut surface can also serve as another optical path interface, offering high flexibility.
[0016] As described above, in the fiber optic probe based on diamond NV color centers, the locking structure may optionally include an annular continuous protrusion that surrounds the entire edge of the receiving hole or surrounds the circumference of the sidewall of the receiving hole corresponding to the position of the diamond particle.
[0017] The ring-shaped continuous protrusions are used for uniform locking along the circumference, resulting in uniform force distribution, high locking strength, and full circumferential constraint on the diamond particles, providing strong resistance to vibration and impact.
[0018] As described above, in the fiber optic probe based on diamond NV color centers, optionally, the locking structure includes multiple dot-shaped protrusions, which are spaced apart at the edge of the receiving hole or spaced apart on the circumference of the sidewall of the receiving hole corresponding to the position of the diamond particle.
[0019] Compared to continuous annular protrusions, point-like protrusions have lower heat input and a smaller heat-affected zone on the optical fiber body and diamond particles, making them particularly suitable for heat-sensitive materials. They not only save processing time and improve manufacturing efficiency, but also effectively prevent diamond particles from detaching.
[0020] In the diamond NV color center-based fiber optic probe described above, the diamond particles may optionally have a particle size of less than 50 micrometers.
[0021] Using small-diameter diamond particles can achieve spatial resolution from submicron to micron, meeting the requirements of high-precision magnetic imaging.
[0022] In the diamond NV color center-based fiber optic probe described above, optionally, the aperture of the receiving hole is 1.04 to 1.1 times the particle size of the diamond particle.
[0023] The size of the receiving hole is slightly larger than that of the diamond particle, which ensures that the diamond particle is inserted without stress and avoids fiber end face breakage. The gap between the two is moderate, and the locking structure only requires a small amount of material backflow to lock it. The diamond particle remains centered in the hole, which is beneficial for optical alignment.
[0024] A second aspect of this application provides a magnetic scanning platform, including an optical fiber probe based on diamond NV centers as described in any of the first aspects above.
[0025] Employing a glue-free, highly stable fiber optic probe, the entire magnetic scanning platform can withstand higher-power laser excitation, resulting in a higher signal-to-noise ratio and measurement speed, while also extending probe lifespan and reducing maintenance costs. Prominent diamond particles ensure high spatial resolution, and the robust probe structure prevents diamond particle detachment, making it suitable for precision measurement scenarios such as semiconductor chip defect detection and metal surface micro-crack detection. It eliminates the need for frequent probe replacements, resulting in low maintenance costs. Attached Figure Description
[0026] The above and other objects, features, and advantages of exemplary embodiments of this application will become readily understood by reading the following detailed description with reference to the accompanying drawings. In the drawings, several embodiments of this application are illustrated by way of example and not limitation, and the same or corresponding reference numerals denote the same or corresponding parts, wherein: Figure 1 This is a schematic diagram of the structure of an optical fiber probe based on diamond NV color centers provided by this utility model.
[0027] Figure 2 A schematic diagram of another fiber optic probe based on diamond NV color centers provided by this utility model; Figure 3 This is a schematic diagram of the structure of a magnetic scanning platform provided by this utility model.
[0028] Explanation of markings in the diagram: 1-Fiber optic cable; 2-Diamond particle; 3-Accepting hole; 4-Seam locking structure; 10-Fiber optic probe; 11-Mount; 12-Microwave source; 13-Antenna; 14-Objective lens; 15-Sample. Detailed Implementation
[0029] The technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.
[0030] like Figure 1 and Figure 2 The diagram shows two structural schematics of fiber optic probes based on diamond NV centers. Figure 1 This is a schematic diagram of a semi-inserted diamond particle design. Figure 2 This is a schematic diagram of a process where diamond particles are fully inserted and then excess tubular sections are removed.
[0031] also, Figure 1 In the example, optical fiber 1 is a solid fiber with a receiving hole 3 machined at its end face to accommodate diamond particles 2. Figure 1 The image above shows a partial insertion of diamond particle 2 into receiving hole 3. Figure 1 The figure below shows a schematic diagram of the locking structure 4 formed by locally fused optical fiber material at the edge of the aperture 3.
[0032] also, Figure 2The optical fiber 1 in the example is a hollow optical fiber or a capillary tube, which has a central hole (i.e., receiving hole 3) to accommodate the diamond particle 2. Figure 2 The image above shows a schematic diagram of diamond particles 2 being completely inserted into the receiving hole 3. Figure 2 The middle image shows a schematic diagram of the partial melting at the location of diamond particle 2. Figure 2 The image below illustrates how the excess portion is cut off after partial melting.
[0033] This embodiment provides an optical fiber probe based on diamond NV color centers, including an optical fiber 1 and a diamond particle 2. A receiving hole 3 is provided on the end face of the optical fiber 1, and the diamond particle 2 is embedded in the receiving hole 3. The aperture of the receiving hole 3 is larger than the particle size of the diamond particle 2. A locking structure 4 formed by partially fused optical fiber material is provided on the edge of the receiving hole 3 or the side wall of the receiving hole 3 corresponding to the position of the diamond particle 2. The locking structure 4 physically locks the diamond particle 2 into the receiving hole 3.
[0034] For example, optical fiber 1 can be any optical fiber capable of guiding light and with a machinable end face or a central hole, such as silica optical fiber, plastic optical fiber, etc. A receiving hole 3 is formed at the end face of optical fiber 1 to receive diamond particles 2. The cross-sectional shape of the receiving hole 3 can be circular, elliptical, or polygonal, preferably circular. The depth of the receiving hole 3 can be either a blind hole or a through hole.
[0035] For example, for solid-core optical fibers, blind holes can be formed using methods such as femtosecond laser ablation, focused ion beam etching, and chemical etching. When diamond particles 2 are placed in the receiving hole 3, they can be partially inserted into the optical fiber 1 (the depth of the receiving hole is less than that of the diamond particles 2). Then, a locking structure 4 is formed at the edge of the receiving hole 3 by local melting to fix it in place. Figure 1 As shown; alternatively, all diamond particles 2 can be placed into the receiving hole 3 (the depth of the receiving hole 3 is greater than that of the diamond particles 2), and then the edge of the hole is melt-locked. In this embodiment, it is preferable that the depth of the receiving hole 3 is less than that of the diamond particles 2, so that the diamond particles 2 can be exposed and thus approach the sample to be tested.
[0036] For hollow optical fibers or capillaries, the central hole serves as the receiving hole 3. Diamond particles 2 are inserted from one end to a predetermined position (they can be fully inserted or partially exposed). Then, localized melting is performed on the sidewall of the receiving hole 3 corresponding to the position of the diamond particles 2, causing the optical fiber material to flow back into the hole to form a locking structure 4, thus locking the diamond particles 2 in place. If the diamond particles 2 are partially exposed, a locking structure can also be formed simultaneously at the edge of the hole. Figure 2 As shown, after all the diamond particles 2 are inserted, the outer side of the tube wall at the location of the particles is partially melted, and after cooling, a locking structure 4 is formed. Then, the excess tube section is cut off to obtain a compact probe.
[0037] Furthermore, when the diamond particle 2 is placed in the receiving hole 3, the diameter of the receiving hole 3 is slightly larger than the particle size of the diamond particle 2 to form a gap fit or transition fit, so that the diamond particle 2 can be placed into the hole without stress, avoiding the breakage of brittle optical fiber materials (especially quartz) due to interference fit. The shape of the diamond particle 2 may be a regular sphere or an irregular sphere. In this embodiment, the particle size refers to the maximum diameter of the diamond particle 2.
[0038] Furthermore, in addition to the clearance fit or transition fit, a locking structure 4 is also adopted. The locking structure 4 is a mechanical blocking structure formed by the local melting of optical fiber material. Specifically, a local heat source such as a femtosecond laser, continuous laser, electric arc, or plasma is used to instantaneously heat the edge of the aperture 3, causing the optical fiber material (such as quartz glass) to undergo a small amount of melting and reflow under the action of surface tension. After cooling, a raised "fastening edge" or solder joint is formed. This structure physically locks the diamond particle 2 into the aperture 3, preventing the diamond particle 2 from falling out, and achieving pure mechanical locking without glue.
[0039] For the locking structure located on the sidewall of the receiving hole corresponding to the position of the diamond particle, the local heat source is directed to the outside of the sidewall, causing the optical fiber material to melt and bulge into the hole, forming a locking structure.
[0040] In other embodiments, the locking structure 4 can also form a protrusion at the edge of the opening by means of mechanical embossing, micro-forming, etc.; the local heat source can be a femtosecond laser, picosecond laser, nanosecond laser, electric arc discharge, hydrogen-oxygen flame, laser-induced plasma, etc.
[0041] This application employs a fully mechanical, adhesive-free fixation method using a receiving hole and localized fusion-locking edge, avoiding the ablation, carbonization, and loss of adhesion of optical adhesive under high-power lasers, ensuring long-term stable operation of the probe. Furthermore, the locking structure is homogeneous with the fiber body, resulting in high fusion bonding strength, preventing diamond particles from easily detaching, and providing excellent vibration and impact resistance. Simultaneously, the absence of a carbonized adhesive layer obstructing the light path keeps the fiber end face and diamond particle surface clean, ensuring that signal collection efficiency does not decay over time and guaranteeing high and stable fluorescence collection efficiency. Moreover, the diamond particles, positioned at the fiber end face, can directly contact the sample under test, meeting resolution and accuracy requirements.
[0042] In one implementation, optical fiber 1 comprises a solid silica optical fiber, and the receiving hole 3 comprises a blind hole formed on the end face of the solid silica optical fiber. Solid silica optical fiber is the most common type of sensing optical fiber, possessing excellent light transmittance and mechanical strength. The receiving hole 3 is a non-penetrating hole (blind hole) formed at the center of the end face of the solid silica optical fiber through precision processing (such as femtosecond laser, ultraviolet laser, focused ion beam, micro-drilling, etc.), with the bottom of the blind hole being the fiber body material. The depth of the blind hole can be determined as needed, typically 20~50μm. Alternatively, borosilicate glass, multi-component glass optical fiber, etc., can also be used.
[0043] Solid-core silica fiber has high light guiding efficiency, making it suitable as a general-purpose probe carrier. A blind aperture is formed on this fiber, resulting in a simple structure, mature processing technology, and easy high-precision positioning. Furthermore, physical support is provided at the bottom of the blind aperture to prevent excessive embedding of diamond particles. For the solid-core fiber solution, the locking structure 4 is located at the edge of the opening of the receiving hole 3.
[0044] In this embodiment, when using solid-core silica fiber, the depth of the receiving hole 3 is preferably smaller than the particle size of the diamond particle 2, so that part of the diamond particle 2 protrudes beyond the end face of the solid-core silica fiber. The depth of the receiving hole 3 (e.g., 20~30μm) is smaller than the particle size of the diamond particle 2 (e.g., 50μm). When the diamond particle is completely embedded in the bottom of the hole, its upper half or most of its volume protrudes beyond the end face of the solid-core silica fiber, and the protrusion height is generally 20%~80% of the diamond particle diameter. The protruding diamond particle 2 can be infinitely close to the surface of the sample to be measured (the spacing can be less than 5μm), realizing near-field measurement, greatly improving spatial resolution and signal strength, and avoiding direct contact between the end face of the solid-core silica fiber and the sample, thus protecting the solid-core silica fiber.
[0045] For applications where near-field measurements are not required, the depth of the receiving hole can be equal to or greater than the diamond particle diameter, allowing the diamond particle to be completely embedded in the hole. The protruding part can be machined into a hemispherical or pointed shape to enhance near-field coupling.
[0046] In another embodiment, the optical fiber 1 includes a hollow-core optical fiber or a capillary tube, and the receiving hole 3 includes a central hole of the hollow-core optical fiber or capillary tube. The hollow-core optical fiber or capillary tube has a central hole extending axially, the inner diameter of which can be precisely controlled through a drawing process. This central hole is directly used as the receiving hole 3 without additional processing; the diamond particle 2 is simply inserted into the central hole from one end to a predetermined position. Furthermore, the hollow-core optical fiber can be a hollow-core photonic crystal fiber or a common hollow-core quartz tube (capillary tube), and the cross-sectional shape of the central hole can be circular, hexagonal, etc. For the hollow-core optical fiber solution, the locking structure 4 is located on the sidewall of the receiving hole 3 corresponding to the position of the diamond particle 2.
[0047] In this situation, it is necessary to control the fiber optic melting point to align with the diamond's location, ensuring that the fused edge structure fixes the diamond within the hollow fiber, preventing it from detaching or sliding further inward. During operation, the diamond's position can be observed through the microscope lens of the fiber optic fusion machine. After confirmation, targeted arc melting can be performed. To facilitate easier observation of the diamond's position, a diamond of a different color from the fiber optic in the observation field can be selected, such as a colored diamond.
[0048] Using hollow optical fibers or capillaries with their own central holes eliminates the need to process blind holes on the fiber end face, significantly simplifying the manufacturing process, reducing costs, and facilitating mass production and quality control using existing standard hollow optical fibers or capillaries.
[0049] The hollow optical fiber or capillary tube has a cut surface on the side of the diamond particle 2 away from the locking structure 4, so that a section of the tube containing the diamond particle 2 forms the probe. After the locking is completed, the excess hollow optical fiber or capillary tube can be cut off at the distal end of the diamond particle 2 (i.e., the side away from the probe end face) (using laser cutting, diamond scalpel scribing, ultrasonic cutting, etc.). After cutting, only a small section of the tube containing the diamond particle 2 (usually hundreds of micrometers to several millimeters in length) is retained, forming a compact probe. Furthermore, the cut surface can be ground to make the diamond particle 2 nearly exposed or exposed, which is beneficial for near-field detection.
[0050] In one implementation, the locking structure 4, formed by local melting, is a continuous annular protrusion. When the locking structure is located at the edge of the orifice, the continuous annular protrusion surrounds the entire edge of the receiving hole 3; when located at the corresponding position on the sidewall, the continuous annular protrusion surrounds the circumference of the outer sidewall of the receiving hole 3 corresponding to the diamond particle. Specifically, the continuous annular protrusion is a protrusion structure formed by uniformly heating the entire edge of the orifice, causing the molten material to flow back uniformly along the circumferential direction. This protrusion is a complete ring shape, with a height generally ranging from a few micrometers to tens of micrometers, and the width depending on the heating parameters. Furthermore, the cross-sectional shape of the annular protrusion can also be semi-circular, triangular, or rectangular. In specific implementations, different ring widths are achieved by controlling the heat source scanning path.
[0051] The ring-shaped continuous protrusions are used for uniform locking along the circumference, resulting in uniform force distribution, high locking strength, and full circumferential constraint on the diamond particles, providing strong resistance to vibration and impact.
[0052] In another implementation, the locking structure 4, formed by local melting, consists of multiple dot-shaped protrusions. When the locking structure is located at the edge of the orifice, the multiple dot-shaped protrusions are spaced apart at the edge of the receiving hole 3; when located at the corresponding position on the sidewall, the multiple dot-shaped protrusions are spaced apart on the outer sidewall of the receiving hole 3 corresponding to the circumference of the diamond particle. Specifically, the dot-shaped protrusions are protrusion structures formed by melting at multiple discrete positions on the edge of the orifice using a pulsed local heat source (such as a femtosecond laser single pulse); the number of dot-shaped protrusions can be 2, 3, 4 or more, and they are usually symmetrically distributed to ensure uniform locking. In addition, the dot-shaped protrusions can also be weld-like, hemispherical or columnar, and the size of the protrusions is controlled by adjusting the pulse energy and pulse number in specific implementations.
[0053] Compared to continuous annular protrusions, point-like protrusions have lower heat input and a smaller heat-affected zone on the optical fiber body and diamond particles, making them particularly suitable for heat-sensitive materials. They not only save processing time and improve manufacturing efficiency, but also effectively prevent diamond particles from detaching.
[0054] In this embodiment, the diamond particle 2 has a particle size of less than 50 micrometers. The diamond particle 2 is a micrometer-sized single-crystal or polycrystalline diamond particle containing NV color centers, with a particle size typically less than 100 μm or less than 200 μm, preferably less than 50 μm, and more preferably 10~30 μm. Furthermore, the diamond particle 2 can be a regular shape (such as spheres or cubes) after grinding and shaping, or it can be an irregular shape. Using small-diameter diamond particles 2 can achieve sub-micrometer to micrometer-level spatial resolution, meeting the requirements of high-precision magnetic imaging.
[0055] When setting the relative dimensions of the receiving hole 3 and the diamond particle 2, the aperture of the receiving hole 3 is 1.04 to 1.1 times the diameter of the diamond particle 2. For example, when the diameter of the diamond particle 2 is 50 μm, the aperture is 52~55 μm. This ratio is a typical gap fit or transition fit, which allows the diamond particle to be easily placed without causing the diamond particle to wobble due to excessive gap. The aperture ratio can be adjusted accordingly for diamond particles 2 of different sizes. For example, for larger particle sizes (above 100 μm), the ratio can be appropriately reduced to 1.02~1.05 times. A micro-interference fit (e.g., 0.99~1.00 times) slightly larger than the diamond particle diameter can also be used, but a more precise pressing process is required.
[0056] The size of the receiving hole is slightly larger than that of the diamond particle, which ensures that the diamond particle is inserted without stress and avoids fiber end face breakage. The gap between the two is moderate, and the locking structure only requires a small amount of material backflow to lock it. The diamond particle remains centered in the hole, which is beneficial for optical alignment.
[0057] like Figure 3As shown, based on the same concept, this embodiment also provides a magnetic scanning platform, including the fiber optic probe based on diamond NV centers as described above. The magnetic scanning platform is a system for imaging and measuring the magnetic field distribution on a sample surface. In addition to the fiber optic probe 10 of this invention, it also includes the following modules: a mounting bracket 11, a microwave source 12, an antenna 13, an objective lens 14, and a sample 15.
[0058] The sample 15 to be tested is fixed on the sample stage, and the end of the fiber optic probe 10 is close to the sample 15. A receiving hole is provided on the end face of the fiber optic probe 10, and diamond particles are embedded in the receiving hole. The aperture of the receiving hole is slightly larger than the particle size of the diamond particles. A locking structure formed by partially melting fiber optic material is provided on the edge of the receiving hole or the side wall of the receiving hole corresponding to the position of the diamond particles, which physically locks the diamond particles in the receiving hole, and a part of the diamond particles protrudes from the end face of the fiber optic probe 10.
[0059] The mounting bracket 11 is used to hold and position the other end of the fiber optic probe 10. The mounting bracket 11 is equipped with a three-dimensional micro-motion adjustment mechanism (such as a manual displacement stage or a piezoelectric ceramic actuator), which can precisely adjust the relative position of the probe and the sample, so that the diamond particles protruding from the end face of the fiber can be close to the sample surface at a spacing of less than 5μm, thereby realizing near-field measurement.
[0060] Microwave source 12 is a frequency-tunable signal generator connected to antenna 13 via a coaxial cable. Antenna 13, employing a coplanar waveguide or a miniature loop antenna, is positioned near the diamond particle on the fiber optic probe 10 (distance <1mm) to apply a microwave field to the NV color center to drive electron spin resonance. The frequency of microwave source 12 can be swept or modulated by the control system.
[0061] Optical system ( Figure 3 The sample (not shown) includes an excitation laser source (laser), a dichroic mirror, an objective lens 14, a filter, and a photodetector (such as an avalanche photodiode, APD, or EMCCD). The excitation light, reflected by the dichroic mirror, is focused by the objective lens 14 and illuminates the diamond particle from the side of the fiber optic probe 10, exciting the NV color center to produce fluorescence. The fluorescence signal is collected by the same objective lens 14, and its intensity is recorded by the detector after passing through the dichroic mirror and filter. The fluorescence intensity changes with the variation of the leakage magnetic field on the sample surface (Zeeman effect), thus determining the magnetic field distribution.
[0062] In addition, it includes a control system, which comprises a computer, data acquisition card, displacement stage controller, and microwave source control software. The control system coordinates scanning motion, microwave frequency switching, signal acquisition, and image reconstruction.
[0063] The magnetic scanning platform operates as follows: The fiber optic probe 10 is mounted on the mounting frame 11. The displacement stage of the fixed sample 15 is adjusted so that the protruding diamond particles are close to the surface of the sample 15 at a distance of <5μm. Laser excitation of the NV color centers is activated, and simultaneously, the microwave source 12 applies a microwave field at the resonant frequency through the antenna 13, causing a resonant dip in the fluorescence intensity of the NV color centers. When a leakage magnetic field exists on the surface of the sample 15, the energy levels of the NV color centers undergo Zeeman splitting, resulting in a shift in the resonant frequency and a change in fluorescence intensity at the fixed microwave frequency. The detector records the fluorescence intensity at that point, reflecting the magnetic field strength at that location. The control system drives the displacement stage to move the sample 15 along a preset path (such as grating scanning), acquiring fluorescence signals point by point. After scanning, the control system converts the signal intensity at each location into a grayscale or pseudo-color image and outputs a magnetic field distribution map of the sample.
[0064] Employing a glue-free, highly stable fiber optic probe, the entire magnetic scanning platform can withstand higher-power laser excitation, resulting in a higher signal-to-noise ratio and measurement speed, while also extending probe lifespan and reducing maintenance costs. Prominent diamond particles ensure high spatial resolution, and the robust probe structure prevents diamond particle detachment, making it suitable for precision measurement scenarios such as semiconductor chip defect detection and metal surface micro-crack detection. It eliminates the need for frequent probe replacements, resulting in low maintenance costs.
[0065] In the foregoing description of this application, unless otherwise expressly specified and limited, the terms "fixed," "installed," "connected," or "linked" should be interpreted broadly. For example, the term "linked" can refer to a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; or it can refer to the internal communication of two components or the interaction between two components. Therefore, unless otherwise expressly limited in this application, those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.
[0066] Based on the above description of this application, those skilled in the art will also understand that terms used, such as "upper," "lower," "length," "width," "top," "bottom," "inner," "outer," "axial," "longitudinal," "transverse," "clockwise," or "counterclockwise," indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings of this application. These terms are used only for the purpose of facilitating the explanation of the application and simplifying the description, and are not intended to imply that the device or element involved must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the aforementioned orientation or positional relationship terms should not be understood or interpreted as limitations on the application.
[0067] Furthermore, the terms "first" or "second," etc., used in this application to refer to numbers or ordinal numbers are for convenience of description only and should not be construed as explicitly or implicitly indicating relative importance or specifying the number of indicated technical features. Also, a feature specified as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, or more, unless otherwise explicitly specified.
[0068] While numerous embodiments of this application have been shown and described herein, it will be appreciated by those skilled in the art that such embodiments are provided by way of example only. Many modifications, alterations, and alternatives will arise in the mind and spirit of this application without departing from its intent. It should be understood that various alternatives to the embodiments of this application described herein may be employed in the practice of this application. The appended claims are intended to define the scope of protection of this application and therefore cover equivalents or alternatives within the scope of these claims.
Claims
1. A fiber optic probe based on diamond NV centers, comprising an optical fiber and diamond particles, characterized in that, A receiving hole is provided on the end face of the optical fiber, the diamond particle is embedded in the receiving hole, and the diameter of the receiving hole is larger than the particle size of the diamond particle; a locking structure formed by partially fused optical fiber material is provided on the edge of the receiving hole or the side wall of the receiving hole corresponding to the position of the diamond particle, and the locking structure physically locks the diamond particle in the receiving hole.
2. The fiber optic probe based on diamond NV color centers according to claim 1, characterized in that, The optical fiber includes a solid quartz optical fiber, and the receiving hole includes a blind hole formed on the end face of the solid quartz optical fiber.
3. The fiber optic probe based on diamond NV color centers according to claim 2, characterized in that, The depth of the receiving hole is less than the particle size of the diamond particle, so that part of the diamond particle protrudes from the end face of the solid quartz optical fiber.
4. The fiber optic probe based on diamond NV color centers according to claim 1, characterized in that, The optical fiber includes a hollow optical fiber or a capillary tube, and the receiving hole includes the central hole of the hollow optical fiber or capillary tube.
5. The fiber optic probe based on diamond NV color centers according to claim 4, characterized in that, The hollow optical fiber or capillary has a cut surface on the side of the diamond particle away from the locking structure, so that a section of the tube including the diamond particle forms a probe.
6. The fiber optic probe based on diamond NV color centers according to claim 1, characterized in that, The locking structure includes a continuous annular protrusion that surrounds the edge of the receiving hole or the sidewall of the receiving hole at the position corresponding to the diamond particle.
7. The fiber optic probe based on diamond NV color centers according to claim 1, characterized in that, The locking structure includes multiple dot-shaped protrusions, which are spaced apart at the edge of the receiving hole or spaced apart on the circumference of the sidewall of the receiving hole corresponding to the position of the diamond particle.
8. The fiber optic probe based on diamond NV color centers according to claim 1, characterized in that, The diamond particles have a diameter of less than 50 micrometers.
9. The fiber optic probe based on diamond NV color centers according to claim 8, characterized in that, The aperture of the receiving hole is 1.04 to 1.1 times the diameter of the diamond particle.
10. A magnetic scanning platform, characterized in that, Including the fiber optic probe based on diamond NV color centers as described in any one of claims 1-9.