Magnetic field measurement method and device based on multi-axial diamond NV color center ensemble, current measurement method and device, electronic equipment and storage medium

Abstract

The invention provides a magnetic field measurement method and device based on a multi-axial diamond NV color center ensemble, a current measurement method and device, electronic equipment and a storage medium. The magnetic field measurement method comprises the following steps: adjusting the pose of a multi-axial diamond NV color center ensemble, so that the included angles between four different axial NV color center shafts and the magnetic field direction of an external magnetic field are the same; the multi-axial diamond NV color center ensemble is excited based on the laser signal, so that the spinning state of the multi-axial diamond NV color center ensemble is polarized to the 0 state; modulating the spin state of the multi-axial diamond NV color center ensemble into + / -1 state according to the spin resonance microwave pulse; obtaining a target spin resonance spectral line according to the fluorescence intensity change of the multi-axial diamond NV color center ensemble in the spin state modulation process; and determining parameter information of the external magnetic field according to the target spin resonance spectral line.

Description

Technical Field

[0001] The present invention relates to the technical field of quantum sensing measurement, and in particular to a magnetic field measurement method and device, a current measurement method and device, an electronic device and a storage medium based on a multi-axial diamond NV color center ensemble. Background Art

[0002] Diamond nitrogen vacancy color center (NV: Nitrogen vacancy, referred to as NV color center) is a structure composed of a nitrogen atom that replaces a carbon atom in the diamond lattice and the adjacent lattice vacancy. This structure can exhibit an extremely long spin coherence time at room temperature, up to milliseconds, and is one of the better solid-state spin quantum systems known so far.

[0003] Based on the electron spin energy level and optical magnetic resonance technology of diamond NV color center, it is possible to measure physical quantities such as magnetic field, temperature, pressure, etc. In addition, since the diamond material itself has the characteristics of high and low temperature resistance, acid and alkali resistance, high pressure resistance, etc., it can maintain stable performance in extreme environments, so the diamond NV color center has important application value in the field of precision measurement.

[0004] However, the inventors of this application have found that since the axial direction of the nitrogen-vacancy axis of the diamond NV color center is consistent with the axial direction of the carbon-carbon bond in the diamond lattice, there are four different axial NV color center axes in single crystal diamond. When the magnetic field is measured based on the optical magnetic resonance technology, the spin energy level resonance energy of the NV color center with different axes is different, which is characterized in actual measurement as different microwave frequencies required to excite the spin energy level resonance.

[0005] In addition, the inventors also found that since two spin resonance lines appear in each axial NV color center, the common four-axial NV color center ensemble may have up to eight resonance lines when measured. This situation results in a lower contrast of the spin resonance signal compared with a single NV color center or a single-axis NV color center ensemble. The large number of split spectral lines also brings great difficulties to the signal distinction and the calculation and analysis of the measurement results.

[0006] The contents of the background technology section are merely the technologies known to the public and do not necessarily represent the existing technologies in the field. Summary of the invention

[0007] According to one aspect of the present invention, the present invention provides a magnetic field measurement method based on a multi-axial diamond NV color center ensemble, and the multi-axial diamond NV color center ensemble includes at least four NV color center axes with different axes. The magnetic field measurement method includes: adjusting the pose of the multi-axial diamond NV color center ensemble so that the angles between the four NV color center axes with different axes and the magnetic field direction of the applied magnetic field are the same; exciting the multi-axial diamond NV color center ensemble based on a laser signal so that the spin state of the multi-axial diamond NV color center ensemble is polarized to the 0 state; modulating the spin state of the multi-axial diamond NV color center ensemble to the ±1 state according to a spin resonance microwave pulse; obtaining a target spin resonance spectrum line according to the change in fluorescence intensity of the multi-axial diamond NV color center ensemble during the spin state modulation process; and determining the parameter information of the applied magnetic field according to the target spin resonance spectrum line.

[0008] According to some embodiments of the present invention, adjusting the pose of the multi-axial diamond NV color center ensemble so that the angles between the four NV color center axes with different axes and the magnetic field direction of the applied magnetic field are the same includes: determining the target crystal orientation of the multi-axial diamond NV color center ensemble; and adjusting the pose of the multi-axial diamond NV color center ensemble so that the target crystal orientation is parallel to the magnetic field direction.

[0009] According to some embodiments of the present invention, adjusting the pose of the multi-axial diamond NV color center ensemble so that the target crystal orientation is parallel to the magnetic field direction includes: adjusting the pose of the multi-axial diamond NV color center ensemble until the spin resonance spectrum lines of the four NV color center axes with different axes completely coincide.

[0010] According to another aspect of the present invention, the present invention further provides a current measurement method based on a multi-axial diamond NV color center ensemble. The current measurement method includes determining corresponding current information according to the parameter information of the applied magnetic field as described above.

[0011] According to another aspect of the present invention, the present invention further provides a magnetic field measurement device based on a multi-axial diamond NV color center ensemble. The magnetic field measurement device includes a multi-axial diamond NV color center ensemble, a pose adjustment module, a laser module, a microwave module, a photoelectric detection module, and a control and calculation module. The pose adjustment module adjusts the pose of the multi-axial diamond NV color center ensemble so that the angles between the four NV color center axes with different axes and the magnetic field direction of the applied magnetic field are the same. The laser module excites the multi-axial diamond NV color center ensemble based on a laser signal so that the spin state of the multi-axial diamond NV color center ensemble is polarized to the 0 state. The microwave module modulates the spin state of the multi-axial diamond NV color center ensemble to the ±1 state according to a spin resonance microwave pulse. The photoelectric detection module obtains a target spin resonance spectrum line according to the change in fluorescence intensity of the multi-axial diamond NV color center ensemble during the spin state modulation process. The control and calculation module determines the parameter information of the applied magnetic field according to the target spin resonance spectrum line.

[0012] According to some embodiments of the present invention, the pose adjustment module determines the target crystal orientation of the multi-axial diamond NV color center ensemble; the pose adjustment module adjusts the pose of the multi-axial diamond NV color center ensemble so that the target crystal orientation is parallel to the magnetic field direction.

[0013] According to some embodiments of the present invention, the pose adjustment module adjusts the pose of the multi-axial diamond NV color center ensemble until the spin resonance spectral lines of the NV color center axes of four different axes completely coincide.

[0014] According to another aspect of the present invention, the present invention also provides a current measuring device based on a multi-axial diamond NV color center ensemble. The current measuring device determines the corresponding current information according to the parameter information of the externally applied magnetic field as described above.

[0015] According to another aspect of the present invention, the present invention also provides an electronic device. The electronic device includes: one or more processors; a storage device for storing one or more programs, and when the one or more programs are executed by the one or more processors, the one or more processors can implement the magnetic field measurement method and / or the current measurement method as described above.

[0016] According to another aspect of the present invention, the present invention also provides a non-volatile computer-readable storage medium. A computer program is stored on the storage medium, and when the computer program is executed by a processor, it can implement the magnetic field measurement method and / or the current measurement method as described above.

[0017] According to another aspect of the present invention, the present invention also provides a computer program product. The computer program product includes: a computer program stored on a computer-readable storage medium; the computer program includes program instructions, and when the program instructions are executed by a computer, the computer executes the magnetic field measurement method and / or the current measurement method as described above.

[0018] Beneficial Effects

[0019] Through the above embodiments, by adjusting the pose of the multi-axial diamond NV color center ensemble, the present invention can make the angles between the NV color center axes of four different axes and the magnetic field direction of the externally applied magnetic field the same, so that the spin resonance spectral lines of the NV color center axes of different axes can coincide, and the visibility of the spin resonance spectral lines is increased to about 4 times, reducing the noise level requirements for key devices such as lasers and photodetectors in the magnetic field quantum sensing system, which is beneficial to the low-cost manufacturing of the system. And through the modulation of the spin state of the multi-axial diamond NV color center ensemble, the present invention can obtain the target spin resonance spectral line based on the change in fluorescence intensity, and then can determine the parameter information of the externally applied magnetic field, thereby completing the magnetic field measurement. Brief Description of the Drawings

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0021] Figure 1 A schematic flowchart showing the magnetic field measurement method according to an embodiment of the present invention;

[0022] Figure 2 Another schematic flowchart showing the magnetic field measurement method according to an embodiment of the present invention;

[0023] Figure 3 A schematic structural diagram showing the carbon atoms in a diamond according to an embodiment of the present invention;

[0024] Figure 4 A schematic diagram showing the spin resonance spectrum of a multi-axial diamond NV color center ensemble before pose adjustment according to an embodiment of the present invention;

[0025] Figure 5 A schematic diagram showing the spin resonance spectrum of a multi-axial diamond NV color center ensemble after pose adjustment according to an embodiment of the present invention;

[0026] Figure 6 A schematic structural diagram showing the magnetic field measurement device according to an embodiment of the present invention.

[0027] Description of reference numerals:

[0028] Magnetic field measurement device 1; Multi-axial diamond NV color center ensemble 10; Pose adjustment module 20; Laser module 30; Microwave module 40; Photoelectric detection module 50; Control and calculation module 60. Detailed implementation manners

[0029] Now, the exemplary embodiments will be described more comprehensively with reference to the drawings. However, the exemplary embodiments can be implemented in various forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that the present invention will be thorough and complete, and the concept of the exemplary embodiments will be fully conveyed to those skilled in the art. Identical reference numerals in the figures denote identical or similar parts, and thus their repeated description will be omitted.

[0030] The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to give a thorough understanding of the embodiments of the present disclosure. However, those skilled in the art will realize that the technical solutions of the present disclosure can be practiced without one or more of these specific details, or other methods, components, materials, devices, etc. may be adopted. In these cases, well-known structures, methods, devices, implementations, materials, or operations will not be shown or described in detail.

[0031] 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 device that includes a series of steps or units is not limited to the listed steps or units, but optionally further includes steps or units not listed, or optionally further includes other steps or units inherent to these processes, methods, products, or devices.

[0032] The terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order.

[0033] The technical solutions of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0034] In practical applications, diamond usually contains multiple NV color centers with different axial directions. Since the nitrogen-vacancy axis of the diamond NV color center is consistent with the direction of the carbon-carbon bond in the diamond, there are also four different axial NV color center axes in the diamond. When performing magnetic field measurement based on the optically detected magnetic resonance technique, when the magnetic field direction of the externally applied magnetic field is inconsistent with the NV color center axis direction, NV color centers with different axial directions will exhibit different spin resonance spectral lines, resulting in a decrease in signal contrast and difficulty in data analysis and magnetic field calculation.

[0035] Based on this, the present invention provides a magnetic field measurement method based on a multi-axial diamond NV color center ensemble.

[0036] Figure 1 A flowchart showing the magnetic field measurement method of the embodiment of the present invention is shown. As Figure 1 shown, the magnetic field measurement method may include steps S100 - S500. Exemplarily, the magnetic field measurement method may be executed by a magnetic field measurement device based on a multi-axial diamond NV color center ensemble with computing capabilities.

[0037] According to an exemplary embodiment, a multi-axial diamond Nitrogen-Vacancy (NV) center ensemble refers to the collection of multiple nitrogen-vacancy (NV) centers in diamond in different axial directions. The multi-axial diamond NV center ensemble can be realized by processes such as nitrogen ion implantation, electron beam irradiation, and high-temperature annealing on single-crystal diamond to prepare NV centers. The multi-axial diamond NV center ensemble typically includes four different axial NV center axes (i.e., nitrogen-vacancy axes).

[0038] In step S100, the magnetic field measurement device adjusts the pose of the multi-axial diamond NV center ensemble so that the angles between the four different axial NV center axes and the magnetic field direction of the applied magnetic field are the same.

[0039] For example, the applied magnetic field can be the magnetic field generated after passing a current through an external wire.

[0040] The magnetic field measurement device includes a pose adjustment module, and the multi-axial diamond NV center ensemble can be arranged on the pose adjustment module. The pose adjustment module can respond to a pose adjustment instruction from a user and perform corresponding pose adjustment on the multi-axial diamond NV center ensemble.

[0041] Exemplarily, the pose adjustment includes but is not limited to adjusting poses such as the pitch angle, heading angle, and roll angle of the multi-axial diamond NV center ensemble, and the present invention does not limit this.

[0042] By adjusting the pose of the multi-axial diamond NV center ensemble, the magnetic field measurement device can make the angles between the four different axial NV center axes of the multi-axial diamond NV center ensemble and the magnetic field direction of the applied magnetic field the same.

[0043] Here, it can be understood that in the prior art, compared with a single NV center, the multi-axial diamond NV center ensemble has the advantage of higher signal intensity, and compared with a single-axial NV center ensemble, it has the advantages of higher preparation technology maturity and lower preparation cost. However, at the same time, due to the existence of four different axial NV center axes in the multi-axial diamond NV center ensemble, there are multiple spin resonance spectral lines with different performances, resulting in low signal contrast and making data analysis and magnetic field calculation difficult.

[0044] In the present invention, when the angles between the NV color center axes in four different axial directions and the magnetic field direction of the externally applied magnetic field are the same, the spin resonance spectral lines generated by the NV color center axes in these four different axial directions will completely overlap and superpose. During the magnetic field measurement process, the spin resonance signals generated by the NV color centers in these four different axial directions are equivalent to those of a single NV color center or a single-axial NV color center ensemble. This can enhance the signal contrast and simplify subsequent data analysis and magnetic field calculation.

[0045] Figure 2 Another schematic flow chart showing the magnetic field measurement method according to an embodiment of the present invention is as follows. As Figure 2 shown, step S100 may further include steps S110 - S120.

[0046] Optionally, in step S110, the magnetic field measurement device determines the target crystal orientation of the multi-axial diamond NV color center ensemble.

[0047] The target crystal orientation is a crystal orientation of the single crystal diamond where the multi-axial diamond NV color center ensemble is located. The target crystal orientation can be custom-selected according to user requirements. Exemplarily, the target crystal orientation can be the

[001] crystal orientation of the diamond.

[0048] Figure 3 A schematic structural diagram of carbon atoms in a diamond according to an embodiment of the present invention is shown.

[0049] As Figure 3 shown, A, B, C, D, and X respectively represent a carbon atom, and there is a carbon-carbon bond between adjacent carbon atoms. The formation of the carbon-carbon bond can be represented by "-". For example, the bond between carbon atom A and carbon atom X can be represented by A-X.

[0050] As Figure 3 shown, the diamond may include a diamond (110) crystal plane and a diamond (110) crystal plane, and the intersection line of the (110) crystal plane and the (110) crystal plane is the

[001] crystal orientation.

[0051] It can be understood here that in the following of the present invention, the

[001] crystal orientation is taken as an example for exemplary introduction. Due to the high symmetry of the diamond lattice, the

[100] crystal orientation,

[100] crystal orientation,

[010] crystal orientation,

[010] crystal orientation, and

[001] crystal orientation are equivalent to the

[001] crystal orientation, and the present invention will not elaborate on them.

[0052] As Figure 3 shown, carbon atoms A, B, and X are all in the (110) crystal plane, so A-X and B-X are also in the (110) crystal plane. Similarly, carbon atoms C, D, and X are all in the (110) crystal plane, so C-X and D-X are also in the (110) crystal plane.

[0053] The carbon atoms of diamond are bonded in the form of sp 3 hybridization, forming four equivalent hybrid orbitals. Due to the tetrahedral symmetry of the sp 3 hybrid orbitals, it can be known that the angle between carbon-carbon bonds is 109°28'. For example, the bond angle between carbon atom A, carbon atom B and carbon atom X can be expressed as bond angle AXB, and bond angle AXB = 109°28'.

[0054] In step S120, the magnetic field measuring device adjusts the pose of the multi-axial diamond NV color center ensemble so that the target crystal orientation is parallel to the magnetic field direction.

[0055] For example, the pose adjustment module can respond to a user instruction to perform corresponding pose adjustment on the multi-axial diamond NV color center ensemble so that the

[001] crystal orientation can be parallel to the magnetic field direction.

[0056] As Figure 3 shown, the

[001] crystal orientation is the intersection line of the (110) crystal plane and the (110) crystal plane, and this intersection line bisects bond angle AXB and bond angle CXD. The

[001] crystal orientation forms an angle of 54°58' with A-X, B-X, C-X and D-X respectively.

[0057] Since the axis formed by the nitrogen atom and the lattice vacancy in the four different axial NV color center axes is consistent with the bonding direction of ordinary carbon atoms, when the magnetic field direction of the applied magnetic field is parallel to the

[001] crystal orientation, the angles between the four different axial NV color center axes and the magnetic field direction are exactly the same, and the spin resonance spectral lines generated will completely overlap.

[0058] Furthermore, when magnetic field measurement is performed under the condition that the spin resonance spectral lines completely overlap, the spin resonance signal can be equivalent to that of a single NV color center or a single-axial NV color center ensemble. Therefore, the signal contrast of the multi-axial diamond NV color center ensemble can be enhanced, making subsequent data analysis and magnetic field calculation simpler.

[0059] Optionally, in step S120, the magnetic field measuring device adjusts the pose of the multi-axial diamond NV color center ensemble until the spin resonance spectral lines of the four different axial NV color center axes completely overlap.

[0060] For example, the magnetic field measuring device can judge whether the target crystal orientation is parallel to the magnetic field direction according to the spin resonance spectra of the four different axial NV color center axes.

[0061] Figure 4 Schematic diagram showing the spin resonance spectrum of the multi-axial diamond NV color center ensemble before pose adjustment according to an embodiment of the present invention; Figure 5Schematic diagram showing the spin resonance spectrum after the pose adjustment of the multi-axial diamond NV color center ensemble according to an embodiment of the present invention.

[0062] Exemplarily, as Figure 4 shown, before the magnetic field measurement device adjusts the pose of the multi-axial diamond NV color center ensemble, the spin resonance spectral lines do not coincide; during the process of the magnetic field measurement device adjusting the pose of the multi-axial diamond NV color center ensemble, the spin resonance spectral lines change. When the spin resonance spectral lines reach complete coincidence (as Figure 5 shown), it can be determined that the target crystal orientation is parallel to the magnetic field direction.

[0063] In step S200, the magnetic field measurement device excites the multi-axial diamond NV color center ensemble based on a laser signal, so that the multi-axial diamond NV color center ensemble is spin-polarized to the 0 state.

[0064] For example, the magnetic field measurement device may further include a laser module, which is used to emit a laser signal. This laser signal can initialize the spin state of the multi-axial diamond NV color center ensemble to the |0> state to ensure that the measurement starts from the known |0> state.

[0065] In step S300, the magnetic field measurement device modulates the spin state of the multi-axial diamond NV color center ensemble to the ±1 state according to the spin resonance microwave pulse.

[0066] For example, the magnetic field measurement device may further include a microwave module, which is used to emit a spin resonance microwave pulse. This spin resonance microwave pulse can modulate the spin state of the multi-axial diamond NV color center ensemble from the |0> state to the |±1> state.

[0067] The present invention can detect the influence of the magnetic field strength of an externally applied magnetic field on the spin energy levels of the multi-axial diamond NV color center ensemble by modulating and detecting the spin state of the multi-axial diamond NV color center ensemble.

[0068] In step S400, the magnetic field measurement device obtains the target spin resonance spectral line according to the change in fluorescence intensity of the multi-axial diamond NV color center ensemble during the spin state modulation process.

[0069] For example, the magnetic field measurement device may further include an optical detection module, which is used to detect the change in fluorescence intensity of the multi-axial diamond NV color center ensemble during the spin state modulation process.

[0070] When the multi-axial diamond NV color center ensemble is in the |0> state, its fluorescence emission intensity is relatively high; when the multi-axial diamond NV color center ensemble is in the |±1> state, its fluorescence emission intensity is relatively low.

[0071] Therefore, by measuring the change in fluorescence intensity, the present invention can determine whether a transition of the spin state of the multi-axial diamond NV color center ensemble from the |0> state to the |±1> state has occurred. The magnetic field measurement device can obtain the target spin resonance spectrum line by detecting the change in fluorescence intensity and as the microwave frequency changes.

[0072] In step S500, the magnetic field measurement device determines the parameter information of the applied magnetic field according to the target spin resonance spectrum line.

[0073] For example, the parameter information of the applied magnetic field includes but is not limited to the magnetic field intensity information, the magnetic field direction information, and the included angle information between the applied magnetic field and the NV color center axes in different axes.

[0074] The magnetic field measurement device may further include a control calculation module, which is electrically connected to the pose adjustment module, the laser module, the microwave module, and the photoelectric detection module, and can synchronously control the pose adjustment module, the laser module, the microwave module, and the photoelectric detection module.

[0075] Under the action of the applied magnetic field, the spin resonance spectrum line of the multi-axial diamond NV color center ensemble will show an offset of the spin resonance frequency, and the offset amount is proportional to the magnetic field intensity. Therefore, according to the relationship between the offset amount of the spin resonance frequency and the magnetic field intensity, the control calculation module can calculate the parameter information of the applied magnetic field.

[0076] Exemplarily, the control calculation module can calculate the corresponding parameter information of the applied magnetic field based on the obtained spin resonance frequency and the NV color center electron spin Hamiltonian equation.

[0077] It can be understood here that when the magnetic field direction of the applied magnetic field is not parallel to the

[001] crystal orientation, the NV color center axes in different axes will show different spin resonance frequencies. At this time, the magnetic field measurement device needs to combine the data of multiple spin resonance spectrum lines to calculate the parameter information of the magnetic field.

[0078] In the present invention, the magnetic field direction of the applied magnetic field is parallel to the

[001] crystal orientation of the diamond, so the spin resonance spectrum lines of the four different axial NV color centers will completely coincide. Based on the coincident spin resonance spectrum lines, the magnetic field measurement device can calculate the parameter information of the applied magnetic field. With such a setting, the present invention can transform the calculation of multiple spin resonance spectrum lines of the multi-axial diamond NV color center ensemble into the calculation of a single spin resonance spectrum line, thereby simplifying the data analysis and magnetic field calculation processes of the present invention.

[0079] Through the above embodiments, by adjusting the pose of the multi-axial diamond NV color center ensemble, the present invention can make the angles between the NV color center axes of four different axes and the magnetic field direction of the externally applied magnetic field the same. As a result, the spin resonance spectral lines of the NV color center axes of different axes can coincide, and the visibility of the spin resonance spectral lines is increased to about 4 times, reducing the requirements for the noise levels of key devices such as lasers and photodetectors in the magnetic field quantum sensing system, which is beneficial to the low-cost manufacturing of the system. In addition, through the modulation of the spin state of the multi-axial diamond NV color center ensemble, the present invention can obtain the target spin resonance spectral line based on the change in fluorescence intensity, and then determine the parameter information of the externally applied magnetic field, thereby completing the magnetic field measurement.

[0080] According to another aspect of the present invention, the present invention also provides a method for measuring current. Exemplarily, this method for measuring current can be executed by a current measurement device with computing capabilities.

[0081] According to the exemplary embodiment, this method for measuring current may include: the current measurement device determines the corresponding current information according to the parameter information of the externally applied magnetic field as described above.

[0082] It can be understood here that in the above magnetic field measurement method, the externally applied magnetic field can be the magnetic field generated after a current is passed through an external wire. Since the magnetic field direction generated by this energized wire is fixed, the current measurement device can determine the current information of this energized wire according to the parameter information of the magnetic field generated by this energized wire, thereby realizing the measurement of the current information.

[0083] According to another aspect of the present invention, the present invention provides a magnetic field measurement device based on a multi-axial diamond NV color center ensemble.

[0084] Figure 6 The structural schematic diagram of the magnetic field measurement device according to the embodiment of the present invention is shown. As Figure 6 shown, the magnetic field measurement device 1 may include a multi-axial diamond NV color center ensemble 10, a pose adjustment module 20, a laser module 30, a microwave module 40, a photoelectric detection module 50, and a control and calculation module 60.

[0085] According to the exemplary embodiment, the pose adjustment module 20 adjusts the pose of the multi-axial diamond NV color center ensemble 10 so that the angles between the NV color center axes of four different axes and the magnetic field direction of the externally applied magnetic field are the same.

[0086] For example, the externally applied magnetic field can be the magnetic field generated after a current is passed through an external wire.

[0087] The multi-axial diamond NV color center ensemble 10 can be disposed on the pose adjustment module 20. The pose adjustment module 20 can respond to a pose adjustment instruction from a user and perform corresponding pose adjustment on the multi-axial diamond NV color center ensemble 10.

[0088] Exemplarily, the pose adjustment includes but is not limited to adjusting poses such as the pitch angle, yaw angle, and roll angle of the multi-axial diamond NV color center ensemble 10, and the present invention does not limit this.

[0089] By adjusting the pose of the multi-axial diamond NV color center ensemble 10, the pose adjustment module 20 can make the angles between the NV color center axes of four different axes of the multi-axial diamond NV color center ensemble 10 and the magnetic field direction of the externally applied magnetic field the same.

[0090] It can be understood here that in the prior art, the multi-axial diamond NV color center ensemble 10 has a higher signal strength advantage compared with a single NV color center, and has a higher preparation technology maturity and a lower preparation cost advantage compared with a single-axial NV color center ensemble. However, at the same time, due to the existence of NV color center axes of four different axes in the multi-axial diamond NV color center ensemble 10, there are multiple spin resonance spectral lines with different performances, resulting in low signal contrast, and making data analysis and magnetic field calculation difficult.

[0091] In the present invention, when the angles between the NV color center axes of four different axes and the magnetic field direction of the externally applied magnetic field are the same, the spin resonance spectral lines generated by the NV color center axes of the four different axes will completely coincide and overlap. Then, during the process of magnetic field measurement, the spin resonance signals generated by the NV color center axes of the four different axes are equivalent to those of a single NV color center or a single-axial NV color center ensemble. In this way, the signal contrast can be enhanced, and subsequent data analysis and magnetic field calculation can be made simpler.

[0092] Optionally, the pose adjustment module 20 determines the target crystal orientation of the multi-axial diamond NV color center ensemble 10.

[0093] The target crystal orientation is a crystal orientation of the single crystal diamond where the multi-axial diamond NV color center ensemble 10 is located. The target crystal orientation can be customarily selected according to user requirements. Exemplarily, the target crystal orientation can be the

[001] crystal orientation of the diamond.

[0094] The structure of carbon atoms in the diamond in the embodiment of the present invention has been described in detail above in combination with Figure 3 and will not be elaborated here.

[0095] The pose adjustment module 20 adjusts the pose of the multi-axial diamond NV color center ensemble 10 so that the target crystal orientation is parallel to the magnetic field direction.

[0096] For example, the pose adjustment module 20 can respond to a user instruction to perform a corresponding pose adjustment on the multi-axial diamond NV color center ensemble 10, so that the

[001] crystal orientation can be parallel to the magnetic field direction.

[0097] As Figure 3 shown, the

[001] crystal orientation is the intersection line of the (110) crystal plane and the (110) crystal plane, and this intersection line bisects the bond angles AXB and CXD. The

[001] crystal orientation forms an angle of 54°58′ with A-X, B-X, C-X, and D-X respectively.

[0098] Since the axial direction formed by the nitrogen atom and the lattice vacancy in the four different axial NV color center axes is consistent with the bonding direction of ordinary carbon atoms, when the magnetic field direction of the externally applied magnetic field is parallel to the

[001] crystal orientation, the angles between the four different axial NV color center axes and the magnetic field direction are exactly the same, and the spin resonance spectral lines generated by them will completely overlap.

[0099] Furthermore, when performing magnetic field measurement under the condition that the spin resonance spectral lines completely overlap, the spin resonance signal can be equivalent to that of a single NV color center or a single-axial NV color center ensemble. Therefore, the signal contrast of the multi-axial diamond NV color center ensemble 10 can be enhanced, making subsequent data analysis and magnetic field calculation simpler.

[0100] Optionally, the pose adjustment module 20 adjusts the pose of the multi-axial diamond NV color center ensemble 10 until the spin resonance spectral lines of the four different axial NV color center axes completely overlap.

[0101] For example, the pose adjustment module 20 can determine whether the target crystal orientation is parallel to the magnetic field direction according to the spin resonance spectrograms of the four different axial NV color center axes.

[0102] Exemplarily, as Figure 4 shown, before the pose adjustment module 20 adjusts the pose of the multi-axial diamond NV color center ensemble 10, the spin resonance spectral lines do not overlap; during the process of the pose adjustment module 20 adjusting the pose of the multi-axial diamond NV color center ensemble 10, the spin resonance spectral lines change. When the spin resonance spectral lines reach complete overlap (as Figure 5 shown), it can be determined that the target crystal orientation is parallel to the magnetic field direction.

[0103] According to the exemplary embodiment, the laser module 30 excites the multi-axial diamond NV color center ensemble 10 based on a laser signal, so that the multi-axial diamond NV color center ensemble 10 is spin-polarized to the 0 state.

[0104] For example, the laser module 30 is used to emit a laser signal. This laser signal can initialize the spin state of the multi-axial diamond NV color center ensemble 10 to the |0> state to ensure that the measurement starts from the known |0> state.

[0105] The microwave module 40 modulates the spin state of the multi-axial diamond NV color center ensemble 10 to the ±1 state according to the spin resonance microwave pulse.

[0106] For example, the microwave module 40 is used to emit a spin resonance microwave pulse. This spin resonance microwave pulse can modulate the spin state of the multi-axial diamond NV color center ensemble 10 from the |0> state to the |±1> state.

[0107] By modulating and detecting the spin state of the multi-axial diamond NV color center ensemble 10, the present invention can detect the influence of the magnetic field strength of the externally applied magnetic field on the spin energy levels of the multi-axial diamond NV color center ensemble 10.

[0108] The photoelectric detection module 50 obtains the target spin resonance spectral line according to the change in fluorescence intensity during the spin state modulation of the multi-axial diamond NV color center ensemble 10.

[0109] For example, the photoelectric detection module 50 is used to detect the change in fluorescence intensity during the spin state modulation of the multi-axial diamond NV color center ensemble.

[0110] When the multi-axial diamond NV color center ensemble 10 is in the |0> state, its fluorescence emission intensity is relatively high; when the multi-axial diamond NV color center ensemble 10 is in the |±1> state, its fluorescence emission intensity is relatively low.

[0111] Therefore, the present invention can judge whether the spin state of the multi-axial diamond NV color center ensemble 10 has undergone a transition from the |0> state to the |±1> state by measuring the change in fluorescence intensity. The photoelectric detection module 50 can obtain the target spin resonance spectral line by detecting the change in fluorescence intensity and as the microwave frequency changes.

[0112] The control and calculation module 60 determines the parameter information of the externally applied magnetic field according to the target spin resonance spectral line.

[0113] For example, the parameter information of the externally applied magnetic field includes but is not limited to the magnetic field strength information, magnetic field direction information of the externally applied magnetic field, and the included angle information between the externally applied magnetic field and the NV color center axes of different axes.

[0114] The control and calculation module 60 is electrically connected to the pose adjustment module 20, the laser module 30, the microwave module 40, and the photoelectric detection module 50, and can synchronously control the pose adjustment module 20, the laser module 30, the microwave module 40, and the photoelectric detection module 50.

[0115] Under the action of an external magnetic field, the spin resonance spectral line of the multi-axial diamond NV color center ensemble 10 will exhibit a shift in the spin resonance frequency, and the shift amount is proportional to the magnetic field strength. Therefore, according to the relationship between the shift amount of the spin resonance frequency and the magnetic field strength, the control calculation module 60 can calculate the parameter information of the external magnetic field.

[0116] Exemplarily, the control calculation module 60 can calculate the corresponding parameter information of the external magnetic field based on the obtained spin resonance frequency and the NV color center electron spin Hamiltonian equation.

[0117] It can be understood here that when the magnetic field direction of the external magnetic field is not parallel to the

[001] crystal orientation, the NV color center axes in different axial directions will exhibit different spin resonance frequencies. At this time, it is necessary to combine the data of multiple spin resonance spectral lines to calculate the parameter information of the magnetic field.

[0118] In the present invention, the magnetic field direction of the external magnetic field is parallel to the

[001] crystal orientation of the diamond, so the spin resonance spectral lines of the four different axial NV color centers will completely coincide. Based on the coincident spin resonance spectral lines, the control calculation module 60 can calculate the parameter information of the external magnetic field. With such a setting, the present invention can transform the calculation of multiple spin resonance spectral lines of the multi-axial diamond NV color center ensemble 10 into the calculation of a single spin resonance spectral line, thereby simplifying the data analysis and magnetic field calculation processes of the present invention.

[0119] Through the above embodiments, the present invention can make the angles between the NV color center axes in four different axial directions and the magnetic field direction of the external magnetic field the same by adjusting the pose of the multi-axial diamond NV color center ensemble, so that the spin resonance spectral lines of the NV color center axes in different axial directions can coincide, and the visibility of the spin resonance spectral line is increased to about 4 times, reducing the noise level requirements for key devices such as lasers and photodetectors in the magnetic field quantum sensing system, which is beneficial to the low-cost manufacturing of the system. And the present invention can obtain the target spin resonance spectral line based on the change in fluorescence intensity through the modulation of the spin state of the multi-axial diamond NV color center ensemble, and then can determine the parameter information of the external magnetic field, thereby completing the magnetic field measurement.

[0120] According to another aspect of the present invention, the present invention also provides a current measurement device.

[0121] According to the exemplary embodiment, the current measurement device can determine the corresponding current information according to the parameter information of the external magnetic field as described above.

[0122] It can be understood here that the externally applied magnetic field can be the magnetic field generated after an electric current is passed through an external wire. Since the direction of the magnetic field generated by the energized wire is fixed, the current measuring device can determine the current information of the energized wire based on the parameter information of the magnetic field generated by the energized wire, thereby enabling the measurement of the current information.

[0123] According to another aspect of the present invention, the present invention also provides an electronic device. The electronic device includes: one or more processors; a storage device for storing one or more programs, which when executed by the one or more processors, enable the one or more processors to implement the magnetic field measurement method and / or the current measurement method as described above.

[0124] According to another aspect of the present invention, the present invention also provides a non-volatile computer-readable storage medium. A computer program is stored on the storage medium, and when the computer program is executed by a processor, it can implement the magnetic field measurement method and / or the current measurement method as described above.

[0125] According to another aspect of the present invention, the present invention also provides a computer program product. The computer program product includes: a computer program stored on a computer-readable storage medium; the computer program includes program instructions, and when the program instructions are executed by a computer, the computer is caused to execute the magnetic field measurement method and / or the current measurement method as described above.

[0126] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions of the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A magnetic field measurement method based on a multi-axial diamond NV color center ensemble, characterized in that: The multi-axial diamond NV color center ensemble includes at least four NV color center axes with different axes, and the magnetic field measurement method includes: Adjusting the posture of the multi-axial diamond NV color center ensemble so that the angles between the four different axial NV color center axes and the magnetic field direction of the external magnetic field are the same; Exciting the multi-axial diamond NV color center ensemble based on a laser signal so that the spin state of the multi-axial diamond NV color center ensemble is polarized to a 0 state; modulating the spin state of the multi-axial diamond NV color center ensemble to a ±1 state according to a spin resonance microwave pulse; Obtaining a target spin resonance spectrum according to the fluorescence intensity change of the multi-axial diamond NV color center ensemble during the spin state modulation process; Parameter information of the external magnetic field is determined according to the target spin resonance spectrum line.

2. The magnetic field measurement method according to claim 1, characterized in that: The step of adjusting the position of the multi-axial diamond NV color center ensemble so that the angles between the four different axial NV color center axes and the magnetic field direction of the external magnetic field are the same includes: determining a target crystal orientation of the multi-axial diamond NV color center ensemble; The pose of the multi-axial diamond NV color center ensemble is adjusted so that the target crystal direction is parallel to the magnetic field direction.

3. The magnetic field measurement method according to claim 1, characterized in that: The step of adjusting the posture of the multi-axial diamond NV color center ensemble so that the target crystal direction is parallel to the magnetic field direction comprises: The position of the multi-axial diamond NV color center ensemble is adjusted until the spin resonance spectra of the four different axial NV color center axes completely overlap.

4. A current measurement method based on a multi-axial diamond NV color center ensemble, characterized in that: The current measurement method comprises: Determine corresponding current information according to parameter information of the external magnetic field as described in any one of claims 1-3.

5. A magnetic field measurement device based on a multi-axial diamond NV color center ensemble, characterized in that: include: Multi-axial diamond NV color center ensemble; A posture adjustment module is used to adjust the posture of the multi-axial diamond NV color center ensemble so that the angles between the NV color center axes of the four different axes and the magnetic field direction of the external magnetic field are the same; A laser module, which excites the multi-axial diamond NV color center ensemble based on a laser signal to polarize the spin state of the multi-axial diamond NV color center ensemble to a 0 state; A microwave module modulates the spin state of the multi-axial diamond NV color center ensemble to a ±1 state according to a spin resonance microwave pulse; A photoelectric detection module, which obtains a target spin resonance spectrum according to the fluorescence intensity change of the multi-axial diamond NV color center ensemble during the spin state modulation process; A control calculation module is used to determine parameter information of the external magnetic field according to the target spin resonance spectrum line.

6. The magnetic field measuring device according to claim 5, characterized in that: The posture adjustment module determines the target crystal orientation of the multi-axial diamond NV color center ensemble; The posture adjustment module adjusts the posture of the multi-axial diamond NV color center ensemble so that the target crystal direction is parallel to the magnetic field direction.

7. The magnetic field measuring device according to claim 5, characterized in that: The posture adjustment module adjusts the posture of the multi-axial diamond NV color center ensemble until the spin resonance spectral lines of the four different axial NV color center axes completely overlap.

8. A current measurement device based on a multi-axial diamond NV color center ensemble, characterized in that: The current measuring device determines corresponding current information according to parameter information of the external magnetic field as described in any one of claims 5-7.

9. An electronic device, characterized in that: include: one or more processors; A storage device for storing one or more programs; When the one or more programs are executed by the one or more processors, the one or more processors implement the magnetic field measurement method as described in any one of claims 1 to 3, and / or, the one or more processors implement the current measurement method as described in claim 4.

10. A non-volatile computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by the processor, the magnetic field measurement method according to any one of claims 1 to 3 is implemented, and / or, when the computer program is executed by the processor, the current measurement method according to claim 4 is implemented.

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