An nv-color center scanning probe, microscope

Abstract

The embodiment of the application discloses a kind of NV color center scanning probe, microscope, the NV color center scanning probe includes diamond carrier, NV color center and microwave radiation mechanism;NV color center is located inside diamond carrier, diamond carrier includes the detection surface towards sample;Microwave radiation mechanism includes metal film belt;Metal film belt is circumferentially arranged around detection surface;Metal film belt is opened with gap in circumference, and the both ends of gap are respectively connected with external circuit, for generating microwave magnetic field when energized.The NV color center scanning probe provided by the embodiment of the application, by setting annular metal film belt on the probe, solve the problem of high power consumption and high thermal load of traditional microwave structure, also ingeniously optimize the performance of NV color center through micro-thermal effect, ensure the consistency of microwave effect in scanning process, provide technical support for high-resolution, high-uniformity NV color center quantum sensing and scanning imaging in extremely low temperature environment.

Description

Technical Field

[0001] The present invention relates to the field of atomic force microscopy, and more particularly to an NV color center scanning probe and a microscope. Background Technology

[0002] Applying microwaves to diamond nitrogen-vacancy color centers (NV centers) in atomic-scale magnetic imaging or scanning magnetic microscopy is the basis for realizing quantum manipulation and readout of their spin states, which directly determines the sensitivity and spatial resolution of precision magnetic imaging based on photodetector magnetic resonance.

[0003] Under current technological conditions, the sensitivity of NV centers is positively correlated with microwave intensity within a certain range. To ensure that NV centers receive sufficient microwave radiation to achieve energy level splitting, it is often necessary to increase the microwave input power, but this leads to significant microwave waste and system heating. Especially in cryogenic systems, the increased heat load will seriously affect system stability. In common quantum experimental dilution cooling systems, even in the base temperature range of 1–2 K, the available cooling capacity is only in the milliwatt range (approximately 1–10 mW); when the temperature drops further to the extremely low temperature range below 100 mK, its cooling capacity will decrease sharply, typically only about 1 mW. Therefore, even the small heat load introduced by microwave power will cause the system to heat up rapidly, making it difficult to maintain the stable low-temperature environment necessary for quantum experiments. If the NV center scanning system is applied to a dilution cooling environment, it faces a dual challenge: on the one hand, the sensitivity of the NV centers needs to be enhanced to make them as close as possible to the microwave radiation structure; on the other hand, to suppress the temperature rise caused by the heating of the microwave structure, the overall ambient temperature needs to be reduced to an extremely low level. However, extremely low temperatures will cause a significant decrease in the optical contrast of the NV centers, thus affecting the detection accuracy and reliability. Summary of the Invention

[0004] This invention provides an NV color center scanning probe and microscope. By setting an annular metal film strip on the probe, the problems of high power consumption and high heat load of traditional microwave structures are solved. It also cleverly optimizes the performance of NV color centers through micro-caloric effects, while ensuring the high consistency of microwave action conditions during scanning. This provides key technical support for high-resolution and high-uniformity NV color center quantum sensing and scanning imaging measurement in extremely low temperature environments.

[0005] In a first aspect, embodiments of the present invention provide an NV color center scanning probe, including a diamond carrier, an NV color center, and a microwave radiation mechanism. The NV color center is disposed inside the diamond carrier, which includes a detection surface facing the sample. The microwave radiation mechanism includes a metal film strip. The metal film strip is attached to the diamond carrier and arranged circumferentially around the detection surface. The heat energy generated by the metal film strip during operation is transferred to the NV color center through the diamond carrier. The metal film strip has a notch in the circumferential direction, and the two ends of the notch are respectively connected to an external circuit to generate a microwave magnetic field.

[0006] Optionally, the diamond carrier is a diamond micropillar; the diamond micropillar includes a first end face, and the NV color center is disposed on the first end face; the metal film strip extends along the axial direction of the diamond micropillar; one side edge of the metal film strip is aligned with the first end face.

[0007] Optionally, the diamond micropillar also includes a second end face opposite to the first end face; the metal film strip is aligned with the second end face on the side opposite to the probe surface.

[0008] Optionally, the microwave radiation mechanism further includes a first lead electrode and a second lead electrode; the sidewall of the diamond micropillar also includes an uncovered area, which is not covered by the metal film strip; the first lead electrode and the second lead electrode are disposed in the uncovered area, one end of the first lead electrode is electrically connected to one end of the notch in the metal film strip, and one end of the second lead electrode is electrically connected to the other end of the notch in the metal film strip; the other ends of the first lead electrode and the second lead electrode both extend to the second end face of the diamond micropillar for connection with an external circuit.

[0009] Optionally, it also includes a diamond substrate, a third lead electrode, and a fourth lead electrode; the side of the diamond carrier facing away from the detection surface is fixedly connected to the diamond substrate; the two ends of the notch in the metal film are electrically connected to the external circuit through the third lead electrode and the fourth lead electrode, respectively.

[0010] Optionally, multiple diamond carriers are disposed on the diamond substrate, and each diamond carrier is provided with an NV color center and a microwave radiation mechanism.

[0011] Optionally, multiple microwave radiating mechanisms are connected in series; an input bus and an output bus are provided on the diamond carrier; each metal film strip includes a first end and a second end along the current transmission direction, the first end and the second end being located at the two ends of the notch respectively; along the current transmission direction, the first end of the first metal film strip is electrically connected to the input bus, the second end of the last metal film strip is electrically connected to the output bus, and in two adjacent metal film strips, the second end of the previous metal film strip is electrically connected to the first end of the next metal film strip.

[0012] Optionally, multiple microwave radiating mechanisms are connected in parallel; an input bus and an output bus are provided on the diamond carrier; each metal film strip includes a first end and a second end along the current transmission direction, the first end and the second end being located at the two ends of the notch respectively; the first end of each metal film strip is electrically connected to the input bus, and the second end of each metal film strip is electrically connected to the output bus.

[0013] Optionally, the metal film strip can be made of gold, copper, or aluminum.

[0014] Optionally, the area of ​​the first end face is smaller than the area of ​​the second end face.

[0015] Optionally, the coverage angle of the metal film strip along the circumference of the detection surface is 260°-280°.

[0016] In a second aspect, embodiments of the present invention also provide a scanning probe microscope, including an atomic force microscopy system for detecting sample surface morphology information and a photodetector magnetic resonance system for detecting sample surface magnetic field distribution information, wherein the atomic force microscopy system includes the NV color center scanning probe of any one of the first aspects.

[0017] This invention provides an NV center scanning probe and microscope. The probe includes a diamond carrier, an NV center located inside the carrier, and a microwave radiation mechanism integrated circumferentially on the carrier's detection surface. This radiation mechanism is composed of an annular metal film strip with notches. The NV center scanning probe structure provided by this invention, by setting an annular metal film strip attached to the diamond carrier on the probe, not only achieves a significant improvement in microwave manipulation efficiency and a significant reduction in heat load, but also cleverly optimizes the performance of the NV center through micro-calorimetry, while ensuring high consistency of microwave action conditions during scanning. This provides key technical support for high-resolution, high-uniformity NV center quantum sensing and scanning imaging measurements in extremely low-temperature environments. Furthermore, the electrode leads of the NV center scanning probe structure provided by this invention can be flexibly extended from the sidewall axial direction or led out from the substrate plane, supporting single-probe or multi-probe (preferably tandem) array integration. Moreover, the scanning probe microscope and atomic force microscopy system integrating this probe can achieve high-sensitivity, high-spatial-resolution synchronous magnetic imaging while realizing nanoscale morphology imaging, and possesses excellent low-temperature compatibility and system stability. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of an NV color center scanning probe provided in an embodiment of the present invention;

[0019] Figure 2 yes Figure 1 The image shown is a top view of the structure of an NV color center scanning probe.

[0020] Figure 3 This is a schematic diagram of another NV color center scanning probe provided in an embodiment of the present invention;

[0021] Figure 4 yes Figure 3 The diagram shows a top view of another NV color center scanning probe.

[0022] Figure 5 This is a schematic diagram of the structure of another NV color center scanning probe provided in an embodiment of the present invention;

[0023] Figure 6 yes Figure 5 The diagram shows a top view of another NV color center scanning probe.

[0024] Figure 7 This is a schematic diagram of a structure in which multiple NV color center scanning probes are connected in series, according to an embodiment of the present invention;

[0025] Figure 8 This is a schematic diagram of a structure in which multiple NV color center scanning probes are connected in series, as provided in an embodiment of the present invention. Detailed Implementation

[0026] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0027] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0028] Figure 1 This is a schematic diagram of the structure of an NV color center scanning probe provided in an embodiment of the present invention. Figure 2 yes Figure 1 The image shows a top view of the structure of an NV color center scanning probe. (Reference) Figure 1 and Figure 2 This invention provides an NV color center scanning probe, including a diamond carrier 1, an NV color center 2, and a microwave radiation mechanism 3. The NV color center 2 is disposed inside the diamond carrier 1, and the diamond carrier 1 includes a detection surface 4 facing the sample. The microwave radiation mechanism 3 includes a metal film strip 31. The metal film strip 31 is attached to the diamond carrier 1 and arranged circumferentially around the detection surface 4. The heat energy generated by the metal film strip 31 during operation is transferred to the NV color center 2 through the diamond carrier 1. The metal film strip 31 has a notch in the circumferential direction, and the two ends of the notch are respectively connected to an external circuit to generate a microwave magnetic field when energized.

[0029] The metal film strip 31 can be understood as a conductive film attached or deposited in the circumferential region near the detection surface 4 of the diamond carrier 1. For example, the metal film strip 31 can be obtained by first depositing a conductive film of about 200 nm thick on the sample surface and then patterning etching. The notch can be understood as a break in the metal film strip 31 in the circumferential direction, which is used to transform the continuous annular film into a radiating structure with two ends so as to connect with the external microwave driving circuit to form a current loop.

[0030] Specifically, the microwave radiation mechanism 3 forms a miniature Ω coil by circumferentially arranged and notched metal film strip 31 near the detection surface 4 of the diamond carrier 1. When an external microwave circuit supplies high-frequency current to the metal film strip 31 through the two ends of the notch, a converging microwave magnetic field is generated at its geometric center (i.e., the location of the NV color center 2), which is used to spin-manipulate the NV color center 2. Compared with a straight wire structure, the Ω-shaped metal film strip, when achieving the same microwave magnetic field strength at the location of the NV color center 2, requires significantly less input current and power consumption under the same detection conditions because the metal film strip 31 is in close contact with the outer wall of the diamond carrier 1, thus significantly reducing the heat generated by the metal film strip 31. At the same time, a small amount of heat is transferred to the NV color center 2 through the diamond carrier 1, so that the heat generation is mainly concentrated on the probe, and the increased temperature is beneficial to improving the contrast of the NV color center 2. Meanwhile, the radiation structure set on the NV color center probe moves synchronously with the probe during operation, always maintaining a fixed distance from NV color center 2. This ensures that the microwave magnetic field acts on NV color center 2 under completely consistent conditions when the distance between the probe and the sample changes, avoiding systematic deviations in signals at different detection points due to changes in distance during scanning, and ultimately improving the uniformity and integrity of the scanning imaging.

[0031] It should be noted that by setting a microwave radiation mechanism 3 on the diamond carrier 1, this application can significantly reduce the microwave power by at least five orders of magnitude, minimizing the heating effect of microwaves on the sample. The cooling power of low-temperature systems (especially at 1K-2K temperatures) is typically only 1-10mW. If the structure of this application is used, the sample temperature can be kept even lower during testing. In contrast, the heating power of existing radiation structures is too high, typically tens of milliwatts to one watt, which would raise the sample temperature to above 5K. At the same time, the core reason for the decrease in continuous wave (CW) contrast of NV centers at low temperatures is that low temperatures suppress phonon-assisted transitions, resulting in a decrease in the optical spin polarization rate and a reduction in the population of the ground state spin state. Simultaneously, the spin-lattice relaxation time is prolonged, reducing the efficiency of microwave flipping of the spin state, and the zero-field splitting parameter changes with temperature, causing microwave resonance detuning. The microwave heating effect generated by the radiation structure set on the NV center probe in this application can raise the temperature of the NV center 2, alleviating the polarization, relaxation, and resonance detuning problems caused by the low temperature, thereby improving the CW contrast.

[0032] Furthermore, the structure of this application can also be used in helium-3 and dilution refrigerator systems, such as a 1mW@100mK dilution refrigerator, which can reduce the temperature of the NV color center scanning system to 100mK.

[0033] This invention provides an NV center scanning probe, comprising a diamond carrier, an NV center, and a microwave radiation mechanism. The NV center is disposed inside the diamond carrier. The diamond carrier includes a detection surface facing the sample, serving as the support substrate for the NV center and the probe detection end, enabling non-contact detection with the sample. The microwave radiation mechanism includes a metal strip. The metal strip is circumferentially arranged around the detection surface. The heat generated by the metal strip during operation is transferred to the NV center through the diamond carrier. A notch is provided circumferentially to form a microwave magnetic field after energization, thereby achieving spin manipulation of the NV center. The NV center scanning probe provided by this invention significantly reduces the heat generated by the radiation structure itself by closely adhering it to the diamond carrier, and transfers most of the heat to the NV center through the diamond carrier, avoiding thermal shock to the sample. This overcomes the problem of excessive heat generation in traditional microwave structures leading to sample temperature rise and disruption of low-temperature experimental conditions. Secondly, the moderate temperature rise (of the probe itself) brought about by the microwave radiation mechanism in this application can effectively promote spin polarization, maintain an appropriate spin relaxation rate, and stabilize resonance conditions, thereby significantly improving the continuous wave (CW) contrast and overall detection signal-to-noise ratio of the NV color center at low temperatures. Finally, by directly integrating the microwave radiation mechanism onto the NV color center scanning probe, the relative position and distance between the microwave radiation mechanism and the NV color center remain strictly fixed at all times, completely eliminating the systematic signal deviation caused by changes in the distance between the microwave source and the NV color center during scanning, and ensuring the uniformity, repeatability, and data integrity of the scanning imaging.

[0034] In one specific embodiment, the physical distance between the microwave radiation source (metal film strip 31) and the NV color center 2 is determined by the radius of the diamond micropillar 10, which in this application can achieve a sub-micrometer radius (e.g., 0.25 micrometers). Compared to conventional methods, in conventional methods, whether the microwave radiation source is set externally or placed on the sample stage, the distance between it and the NV color center 2 is greater than 50 micrometers. Compared to conventional structures, the structure of this application shortens the distance between the microwave radiation source and the NV color center 2 by more than two orders of magnitude, which allows the required injected microwave power to be reduced by five orders of magnitude to generate the same intensity of the control magnetic field at the NV color center.

[0035] In an optional embodiment, the metal film strip 31 has a coverage angle of 260°-280° around the detection surface 4.

[0036] Specifically, the metal film strip 31 is arranged circumferentially around the detection surface 4, with a preferred coverage angle of 260°-280° (approximately 3 / 4 of a circle). This angle range is the result of a trade-off between theoretical ideal values ​​and practical manufacturing. Theoretically, a complete but not closed ring (360°) can maximize magnetic field efficiency, but its fabrication is extremely difficult and carries a risk of short circuits. In a specific embodiment, the width of the metal film strip 31 is 100-200 nm, forming a 3 / 4-circle (approximately 270°, i.e., a 90° gap) annular structure, ensuring fabrication feasibility while still providing extremely high magnetic field focusing efficiency. The microwave magnetic field strength generated by the approximately 3 / 4-circle annular structure at its geometric center (i.e., the location of the NV color center 2) is approximately... Where r is the radius of the ring and I is the driving current. Let be the permeability of free space. This is in contrast to the magnetic field at a distance L of an infinitely long straight conductor. Under the same drive current I, by substituting typical dimensions (e.g. , Calculations show that the magnetic field strength at the center of a 270° (i.e., a 90° gap) annular metal film strip 31 is equal to that of a straight conductor at 50°. The magnetic field strength is approximately 471 times that at the location of the NV color center 2, corresponding to a radiation efficiency increase of approximately 26.7 dB. Therefore, while maintaining the microwave manipulation magnetic field strength at the location of NV color center 2, the required injected microwave power can be reduced by five orders of magnitude, or 53.5 dB (471 × 471 ≈ 2.2 × 10^5), making the Joule heating of the coil itself negligible. More importantly, the extremely low overall power consumption means that the overall temperature of the sample stage (cryostat) is almost unaffected, which to some extent solves the global thermal disturbance problem caused by traditional long wire schemes, especially in ultra-low temperature quantum experiments at the milliKelvin level.

[0037] Figure 3 This is a schematic diagram of another NV color center scanning probe provided in an embodiment of the present invention. Figure 4 yes Figure 3 A top view of another NV color center scanning probe is shown. (Reference) Figure 3 and Figure 4 In an optional embodiment, the diamond carrier 1 is a diamond micropillar 10; the diamond micropillar 10 includes a first end face 11, and the NV color center 2 is disposed on the first end face 11; the metal film strip 31 extends along the axial direction of the diamond micropillar 10; one side edge of the metal film strip 31 is aligned with the first end face 11.

[0038] Specifically, the diamond carrier 1 is a diamond micropillar 10, shaped as a cylinder for easy processing or a truncated cone to enhance the field strength. The NV color center 2 is located on its first end face 11. A metal film strip 31 is prepared extending along the axial direction of the diamond micropillar 10, with one edge aligned with the first end face 11 (the plane where the NV color center 2 is located). Aligning the upper edge of the metal film strip 31 with the end face where the NV color center 2 is located means that the path through which the microwave current flows is closer to the NV color center 2. According to the Biot-Savart law, the magnetic field strength generated by the current element is inversely proportional to the square of the distance. Therefore, this arrangement ensures that the magnetic field generated by the current acts on the NV color center 2 with the shortest distance and minimal attenuation, maximizing the magnetic field coupling efficiency and thus increasing the influence of the microwave magnetic field on the sample.

[0039] In an optional embodiment, the diamond micropillar 10 further includes a second end face opposite to the first end face 11, the area of ​​the first end face 11 being smaller than the area of ​​the second end face.

[0040] Specifically, the diamond micropillar 10 is a truncated cone, with the area of ​​its first end face 11 (top) smaller than the area of ​​its second end face (bottom). In a preferred size example, the top diameter is approximately 0.5 micrometers, the bottom diameter is approximately 1 micrometer, and the height is approximately 3 micrometers, with a single NV color center located at the top region of the micropillar. This top-to-bottom tapering geometry makes it easier to form the NV color center 2 at the top during fabrication, resulting in more precise positioning of the NV color center 2. Furthermore, the larger bottom area provides a stable supporting substrate for the micropillar, improving the mechanical strength of the structure. The tapered side structure also facilitates the collection and upward conduction of fluorescence emitted by the NV color center 2, while simultaneously helping to further concentrate microwave energy at the top NV color center, improving coupling efficiency.

[0041] Figure 5 This is a schematic diagram of another NV color center scanning probe provided in an embodiment of the present invention. Figure 6 yes Figure 5 The image shows a top view of another NV color center scanning probe. (Reference) Figure 5 and Figure 6 In an optional embodiment, the diamond micropillar 10 further includes a second end face opposite to the first end face 11; the metal film strip 31 is aligned with the second end face on the side opposite to the probe surface 4.

[0042] The second end face can be understood as the bottom plane of the diamond micropillar 10, which is also the interface connecting the diamond micropillar 10 and the diamond substrate 40 or support structure. Generally, the diamond micropillar 10 and the diamond substrate 40 are integrally formed through a polishing process. For example, a truncated cone-shaped micropillar can be fabricated on an electronic-grade diamond substrate using focused ion beam or reactive ion etching processes. An NV color center 2 is then formed at the top of the micropillar through ion implantation and annealing processes to form the diamond micropillar 10 and diamond substrate 40 structure of this application.

[0043] For details, please refer to Figure 5 and Figure 6 In this embodiment, the metal film strip 31 extends along the side of the diamond micropillar 10, with its edge facing away from the probe surface 4 aligned with the second end face (bottom plane) of the diamond micropillar. The complete metal capping layer provides additional mechanical reinforcement and a better heat conduction path for the micropillar, facilitating heat dissipation from the probe tip to the bottom substrate and improving the thermal stability of the device at low temperatures. Furthermore, the alignment of the lower edge of the metal film strip 31 with the bottom plane facilitates the subsequent fabrication of large-area contact electrodes from the bottom plane, simplifying electrical interconnections.

[0044] Continue to refer to Figure 3 and Figure 4 In an optional embodiment, the microwave radiation mechanism 3 further includes a first lead electrode 32 and a second lead electrode 33; the sidewall of the diamond micropillar 10 also includes an uncovered area, which is not covered by the metal film strip 31; the first lead electrode 32 and the second lead electrode 33 are disposed in the uncovered area, one end of the first lead electrode 32 is electrically connected to one end of the notch in the metal film strip 31, and one end of the second lead electrode 33 is electrically connected to the other end of the notch in the metal film strip 31; the other ends of the first lead electrode 32 and the second lead electrode 33 both extend to the second end face of the diamond micropillar 10 for connection with an external circuit.

[0045] For details, please refer to Figure 3 and Figure 4 On the sidewall of the diamond micropillar 10, there exists an uncovered area not covered by the metal film strip 31. One end of the first lead electrode 32 is directly electrically connected to one end of the notch in the metal film strip 31, and one end of the second lead electrode 33 is directly electrically connected to the other end of the notch in the metal film strip 31. The other ends of both lead electrodes extend downward along the surface of the uncovered area until they reach the second end face of the diamond micropillar 10.

[0046] It should be noted that the first lead electrode 32 and the second lead electrode 33 shown in the figure are exemplary structures extending axially along the sidewall of the diamond micropillar 10. In actual implementation, the specific connection path of the lead electrode can be designed according to the requirements of process conditions, electrical performance, or spatial layout. For example, it can be connected to both ends of the notch of the metal film strip 31 by spiral extension along the sidewall, zigzag extension, or other spatial routing methods, and finally extend to the second end face. As long as a specific connection structure can reliably lead external microwave signals to the metal film strip 31 and meet the electrical isolation requirements, it falls within the protection scope of this invention, and the embodiments of this invention do not limit it in this regard.

[0047] In one specific embodiment, the metal film can be patterned using focused ion beam etching or electron beam lithography combined with a lift-off process to obtain the first lead electrode 32 and the second lead electrode 33. For example, a metal strip approximately 100-200 nm wide is retained on the sidewall of the diamond micropillar as the first lead electrode 32 or the second lead electrode 33. This metal strip starts from electrode A at the bottom of the micropillar, spirals upwards along the sidewall of the micropillar for approximately 3 / 4 of a turn, and then terminates.

[0048] In an optional embodiment, it further includes a diamond substrate 40, a third lead electrode 34, and a fourth lead electrode 35; the side of the diamond carrier 1 facing away from the detection surface 4 is fixedly connected to the diamond substrate 40; the two ends of the notch in the metal film strip 31 are electrically connected to an external circuit through the third lead electrode 34 and the fourth lead electrode 35, respectively.

[0049] Specifically, the bottom of the diamond carrier 1 (such as the diamond micropillar 10) (i.e., the side facing away from the detection surface 4) is fixedly connected to the diamond substrate 40, and the metal film strip 31 is electrically connected to the external circuit through the third lead electrode 34 and the fourth lead electrode 35. Specifically, one end of the third lead electrode 34 is electrically connected to one end of the notch in the metal film strip 31, and the other end of the third lead electrode 34 is electrically connected to the external circuit. One end of the fourth lead electrode 35 is electrically connected to the other end of the notch in the metal film strip 31, and the other end of the fourth lead electrode 35 is electrically connected to the external circuit. The main body of both lead electrodes is fabricated on the surface of the diamond substrate 40 and extends to the edge of the substrate or a specific pad location. The third lead electrode 34 and the fourth lead electrode 35 can adopt different forms according to design requirements. For example, they can be large-area contact electrodes (such as...) Figure 6 As shown, large-area contact electrodes help form more reliable low-resistance ohmic contacts and facilitate external bonding. Alternatively, the third lead electrode 34 and the fourth lead electrode 35 can also be designed as narrow-line leads or other forms to adapt to high-density integration or specific signal transmission requirements. This invention does not limit the specific shape and size of the electrodes.

[0050] For example, refer to Figure 4 and Figure 5 There are two possible implementation paths for the electrical connection between the third lead electrode 34 and the fourth lead electrode 35 and the metal film strip 31: such as Figure 4 As shown, the third lead electrode 34 and the fourth lead electrode 35 can first merge with the first lead electrode 32 and the second lead electrode 33 at a suitable position on the bottom or sidewall of the diamond carrier 1 to form an electrical connection, and then indirectly connect to the metal film strip 31 through the first lead electrode 32 and the second lead electrode 33. This method provides greater design flexibility for electrode routing, such as bypassing certain structures or optimizing wiring. Figure 5 As shown, the third lead electrode 34 and the fourth lead electrode 35 can be directly fabricated on the surface of the diamond substrate 40 and extend upwards, so that their ends directly contact the two ends of the notch in the metal film strip 31 and form an electrical connection. This method has the shortest connection path, which helps to reduce parasitic resistance and inductance.

[0051] Continue to refer to Figure 6 In an optional embodiment, a plurality of diamond carriers are disposed on the diamond substrate.

[0052] For details, please refer to Figure 6 Multiple diamond carriers 1 (such as diamond micropillars 10) are disposed on a diamond substrate, and the microwave radiation mechanisms 3 (metal film strips 31) of these diamond carriers 1 are arranged in series. That is, the third lead electrode 34 of one carrier is electrically connected to the fourth lead electrode 35 of the adjacent carrier. When there are multiple diamond carriers 1, they are connected in this manner so that all the metal film strips 31 in the entire array form a series loop. The external microwave driving circuit only needs to apply a driving signal through the start and end ports of this loop, and the microwave current can flow through the metal film strips 31 of each carrier in sequence, generating a local microwave magnetic field at each metal film strip 31. In the series design, a single driving source can synchronously control the entire array while maintaining the same current flowing through each carrier, ensuring the consistency of the microwave control field strength received by each NV color center 2. Compared with the parallel scheme, the driving architecture is greatly simplified while realizing the parallel operation of multiple probes. It should be noted that multiple carriers can also be arranged in parallel. However, in the parallel configuration, the total drive current will be split across multiple branches, and the total current in the circuit will increase exponentially, resulting in higher overall power consumption and heat generation than in the series configuration.

[0053] Similarly, multiple independent diamond carriers 1 can be fabricated on the substrate to achieve independent addressing and parallel manipulation of multiple NV color centers 2, or to prepare them in batches.

[0054] Figure 7 This is a schematic diagram of a structure in which multiple NV color center scanning probes are connected in series, according to an embodiment of the present invention. (Reference) Figure 7Multiple microwave radiating mechanisms 3 are connected in series; an input bus 36 and an output bus 37 are provided on the diamond carrier 1; each metal film strip 31 includes a first end 38 and a second end 39 along the current transmission direction, the first end 38 and the second end 39 are respectively located at the two ends of the notch of the metal film strip 31; along the current transmission direction, the first end 38 of the first metal film strip 31 is electrically connected to the input bus 36, the second end 39 of the last metal film strip 31 is electrically connected to the output bus 37, and in two adjacent metal film strips 31, the second end 39 of the previous metal film strip 31 is electrically connected to the first end 38 of the next metal film strip 31.

[0055] Specifically, in the series design, a single drive source can synchronously control the entire array, and the current flowing through each diamond carrier 1 is equal, thus ensuring a highly consistent microwave control field strength at each NV color center 2. Compared to the parallel scheme, the series architecture significantly simplifies the drive circuit design while enabling parallel operation of multiple probes, and also requires lower drive power.

[0056] Figure 8 This is a schematic diagram of a structure in which multiple NV color center scanning probes are connected in parallel, according to an embodiment of the present invention. (Reference) Figure 8 Multiple microwave radiation mechanisms are connected in parallel; an input bus 36 and an output bus 37 are provided on the diamond carrier 1; each metal film strip 31 includes a first end 38 and a second end 39 along the current transmission direction, the first end 38 and the second end 39 are respectively located at the two ends of the notch; the first end 38 of each metal film strip 31 is electrically connected to the input bus 36, and the second end 39 of each metal film strip 31 is electrically connected to the output bus 37.

[0057] Specifically, in the parallel design, the total drive current is split in multiple branches, and the total loop current increases exponentially with the number of probes, resulting in significantly higher overall power consumption and heat generation than the series scheme.

[0058] In summary, the serial architecture is the preferred embodiment of this invention, offering lower power consumption and a simpler drive structure while ensuring consistent operation. It should be noted that the parallel architecture can also achieve parallel multi-probe detection and can be used as an alternative, but attention should be paid to potential thermal management issues arising from high-density integration.

[0059] In an optional embodiment, the metal film strip 31 is made of gold, copper, or aluminum.

[0060] Specifically, the metal film strip 31 can be made of gold, copper, or aluminum. In actual processes, in order to improve the adhesion and long-term stability of the metal film strip 31 to the diamond surface, an adhesion enhancement layer (such as chromium Cr or titanium Ti) can be deposited on the diamond surface before depositing the metal film strip 31, and then gold, copper, or aluminum can be deposited to form the metal film strip 31.

[0061] This invention also provides a scanning probe microscope, comprising an atomic force microscopy system for detecting sample surface morphology information and a photodetector magnetic resonance system for detecting sample surface magnetic field distribution information. The atomic force microscopy system includes the NV center scanning probe described in the above embodiments. The tip of the NV center scanning probe serves as the physical probe of the atomic force microscopy system, used to sense the sample morphology; its internal NV center 2 acts as a quantum magnetic sensor, used to detect the magnetic field. During operation, the atomic force microscopy system maintains a constant interaction force between the probe and the sample through feedback control, thereby simultaneously obtaining the morphology information of the sample surface. Simultaneously, the photodetector magnetic resonance system manipulates the NV center 2 through a microwave radiation mechanism 3 and collects its fluorescence signal, decoding the magnetic field information at the corresponding scanning position. The scanning probe microscope provided by this invention, by integrating the NV center scanning probe described in the above embodiments, possesses all its functions and beneficial effects.

[0062] In one specific embodiment, the detection magnetic resonance system connects a microwave signal source (frequency approximately 2.87 GHz, corresponding to the splitting of the ground state energy level of the NV color center) to both ends of the metal film strip 31 via a high-frequency coaxial cable. Through optical detection magnetic resonance technology testing, significant NV color center spin Rabi oscillations can be observed at extremely low microwave input power (e.g., -10 dBm) without the need for a microwave power amplifier, confirming the efficient microwave radiation capability of this embodiment. Simultaneously, the temperature change before and after microwave injection is far less than that when using a conventional copper wire solution.

[0063] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, combinations, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. An NV color center scanning probe, comprising a diamond carrier, an NV color center, and a microwave radiation mechanism, wherein the NV color center is disposed inside the diamond carrier, and the diamond carrier includes a detection surface facing the sample, characterized in that: The microwave radiation mechanism includes a metal film strip; The metal film strip is attached to the diamond carrier and arranged circumferentially around the detection surface. The heat generated by the metal film strip during operation is transferred to the NV color center through the diamond carrier. The metal film strip has a notch in the circumferential direction, and the two ends of the notch are respectively connected to an external circuit to generate a microwave magnetic field.

2. The NV color center scanning probe according to claim 1, characterized in that, The diamond carrier is a diamond micropillar; The diamond micropillar includes a first end face, and the NV color center is disposed on the first end face; The metal film strip extends along the axial direction of the diamond micropillar; One edge of the metal film strip is aligned with the first end face.

3. The NV color center scanning probe according to claim 2, characterized in that, The diamond micropillar also includes a second end face opposite to the first end face; The metal film strip is aligned with the second end face on the side opposite to the detection surface.

4. The NV color center scanning probe according to claim 2, characterized in that, The microwave radiation mechanism further includes a first lead electrode and a second lead electrode; The sidewalls of the diamond micropillars also include uncovered areas, which are not covered by the metal film strip; The first lead electrode and the second lead electrode are disposed in the uncovered area. One end of the first lead electrode is electrically connected to one end of the notch in the metal film strip, and one end of the second lead electrode is electrically connected to the other end of the notch in the metal film strip. The other ends of the first lead electrode and the second lead electrode both extend to the second end face of the diamond micropillar for connection to an external circuit.

5. The NV color center scanning probe according to claim 1, characterized in that, It also includes a diamond substrate, a third lead electrode, and a fourth lead electrode; The side of the diamond carrier facing away from the detection surface is fixedly connected to the diamond substrate; The two ends of the notch in the metal film are electrically connected to the external circuit through the third lead electrode and the fourth lead electrode, respectively.

6. The NV color center scanning probe according to claim 5, characterized in that, The diamond substrate is provided with a plurality of diamond carriers, and each diamond carrier is provided with the NV color center and the microwave radiation mechanism.

7. The NV color center scanning probe according to claim 6, characterized in that, The multiple microwave radiation mechanisms are connected in series; The diamond carrier is provided with an input bus and an output bus; Each of the metal film strips includes a first end and a second end along the current transmission direction, the first end and the second end being located at the two ends of the notch, respectively; Along the current transmission direction, the first end of the first metal film strip is electrically connected to the input bus, the second end of the last metal film strip is electrically connected to the output bus, and in two adjacent metal film strips, the second end of the previous metal film strip is electrically connected to the first end of the next metal film strip.

8. The NV color center scanning probe according to claim 6, characterized in that, The multiple microwave radiation mechanisms are connected in parallel; The diamond carrier is provided with an input bus and an output bus; Each of the metal film strips includes a first end and a second end along the current transmission direction, the first end and the second end being located at the two ends of the notch, respectively; The first end of each of the metal film strips is electrically connected to the input bus, and the second end of each of the metal film strips is electrically connected to the output bus.

9. The NV color center scanning probe according to claim 1, characterized in that, The metal film strip is made of gold, copper, or aluminum.

10. The NV color center scanning probe according to claim 3, characterized in that, The area of ​​the first end face is smaller than the area of ​​the second end face.

11. The NV color center scanning probe according to claim 1, characterized in that, The coverage angle of the metal film strip along the circumference of the detection surface is 260°-280°.

12. A scanning probe microscope, characterized in that, It includes an atomic force microscopy system for detecting sample surface morphology information and a photodetector magnetic resonance system for detecting sample surface magnetic field distribution information, wherein the atomic force microscopy system includes the NV color center scanning probe as described in any one of claims 1-11.

Images