Magnetic field measuring device and magnetic field measuring method

Abstract

To efficiently apply a magnetic field corresponding to a measurement object magnetic field by a flux transformer, and to facilitate a relative arrangement of a magnetic resonance member, a high frequency generator, a magnet, and magnetic flux of the flux transformer, so as to allow a radiation space of laser light to be easily secured for measurement of the magnetic field.SOLUTION: A high frequency magnetic field generator 2 applies a micro wave to a magnetic resonance member 1 which is capable of performing an electron spin quantum operation by the micro wave. A magnet 3 applies a static magnetic field to the magnetic resonance member 1. A radiation device 12 radiates light of a specific wave length to the magnetic resonance member 1. A flux transformer 4 receives a measurement object magnetic field with a primary coil 4a, and applies an application magnetic field corresponding to the received measurement object magnetic field to the magnetic resonance member 1 with a secondary coil 4b. The magnetic resonance member 1 is arranged in a hollow section of the secondary coil 4b of the flux transformer 4, and further arranged at a position in a hollow section of the magnet 3.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a magnetic field measuring device and a magnetic field measuring method. [Background technology]

[0002] A certain magnetic field measuring device performs magnetic measurement by optically detected magnetic resonance (ODMR) using the electron spin resonance of a sensing member such as a diamond structure having nitrogen and lattice defects (NV center) (see, for example, Patent Document 1). In ODMR, a static magnetic field is applied to a magnetic resonance member such as diamond having such an NV center in addition to the magnetic field to be measured, and laser light (excitation light and measurement light) and microwaves are applied in a predetermined sequence, the amount of fluorescent light emitted from the magnetic resonance member is detected, and the magnetic flux density of the magnetic field to be measured is derived based on the amount of light.

[0003] For example, in the Ramsey pulse sequence, (a) excitation light is applied to the NV center, (b) a first π / 2 pulse of microwaves is applied to the NV center, (c) a second π / 2 pulse of microwaves is applied to the NV center at a predetermined time interval tt from the first π / 2 pulse, (d) measurement light is applied to the NV center to measure the amount of light emitted by the NV center, and (e) the magnetic flux density is derived based on the measured amount of light emitted. Also, in the spin echo pulse sequence, (a) excitation light is applied to the NV center, (b) a first π / 2 pulse of microwaves is applied to the NV center at a phase of 0 degrees of the measured magnetic field, (c) a π pulse of microwaves is applied to the NV center at a phase of 180 degrees of the measured magnetic field, (d) a second π / 2 pulse of microwaves is applied to the NV center at a phase of 360 degrees of the measured magnetic field, (e) measurement light is applied to the NV center to measure the amount of light emitted by the NV center, and (f) the magnetic flux density is derived based on the measured amount of light emitted.

[0004] Furthermore, one magnetic sensor includes a superconducting quantum interference device (SQUID) and a flux transformer that detects the magnetic field to be measured using a pickup coil and applies it to the SQUID using an input coil (see, for example, Patent Document 2). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2020-8298 A [Patent Document 2] Japanese Patent Application Publication No. 8-75834 Summary of the Invention [Problem to be solved by the invention]

[0006] The above-mentioned magnetic field measuring device applies a laser beam, a microwave, and a static magnetic field to the magnetic resonance member in addition to the magnetic field to be measured, and therefore, means for applying the laser beam, the microwave, and the static magnetic field are mounted around the magnetic resonance member. Therefore, when applying the laser beam, the microwave, and the static magnetic field to the magnetic resonance member, in order to use a flux transformer, it is necessary to arrange the secondary coil of the flux transformer without interfering with the application of the laser beam, the microwave, and the static magnetic field, and due to the geometrical configuration, it is difficult for the flux transformer to efficiently apply a magnetic field corresponding to the magnetic field to be measured to the magnetic resonance member.

[0007] The present invention has been made in consideration of the above problems, and aims to provide a magnetic field measuring device and a magnetic field measuring method in which a magnetic field corresponding to the magnetic field to be measured is efficiently applied to a magnetic resonance component by a flux transformer, and the magnetic resonance component, high-frequency generator, and magnet are easily arranged relative to the direction of the magnetic flux of the flux transformer, making it easy to secure space for irradiating laser light. [Means for solving the problem]

[0008] The magnetic field measuring device according to the present invention includes a magnetic resonance member capable of quantum manipulation of electron spins with microwaves, a high-frequency magnetic field generator for applying microwaves to the magnetic resonance member, a magnet for applying a static magnetic field to the magnetic resonance member, an irradiation device for irradiating the magnetic resonance member with light of a specific wavelength, and a flux transformer for sensing a magnetic field to be measured with a primary coil and applying an applied magnetic field corresponding to the sensed magnetic field to the magnetic resonance member with a secondary coil. The high-frequency magnetic field generator is disposed in a hollow part of the secondary coil of the flux transformer, and the magnetic resonance member is disposed at a position that is in the hollow part of the secondary coil of the flux transformer and in the hollow part of the magnet. Furthermore, the direction in which the secondary coil penetrates the hollow part coincides with the direction in which the magnet penetrates the hollow part. The irradiation device is configured to irradiate the magnetic resonance member with the light in a direction parallel to the axis of the magnetic resonance member and a direction in which the secondary coil penetrates the hollow portion of the magnetic resonance member. and The direction of the magnet's hollow space is aligned with the direction of the magnet's hollow space. And through an opening between two currents that are conducted to emit microwaves in the high frequency magnetic field generator, The magnetic resonance member is irradiated with the light described above.

[0009] The magnetic field measuring method according to the present invention includes (a) sensing a magnetic field to be measured with a primary coil of a flux transformer, (b) applying a magnetic field corresponding to the sensed magnetic field to be measured with a secondary coil of the flux transformer to a magnetic resonance member capable of electron spin quantum manipulation with microwaves, applying microwaves to the magnetic resonance member, applying a static magnetic field to the magnetic resonance member, and irradiating the magnetic resonance member with light of a specific wavelength. A high-frequency magnetic field generator that applies microwaves to the magnetic resonance member is disposed in a hollow part of the secondary coil of the flux transformer, and the magnetic resonance member is disposed at a position that is in the hollow part of the secondary coil of the flux transformer and in the hollow part of a magnet that applies the static magnetic field to the magnetic resonance member. Furthermore, the direction in which the secondary coil penetrates the hollow part coincides with the direction in which the magnet penetrates the hollow part. The direction of the light irradiation to the magnetic resonance member and the direction of the penetration of the hollow portion of the secondary coil and The direction of the magnet's hollow space is aligned with the direction of the magnet's hollow space. And through an opening between two currents that are conducted to emit microwaves in the high frequency magnetic field generator, The magnetic resonance member is irradiated with the light described above. Effect of the Invention

[0010] According to the present invention, a magnetic field measuring device and a magnetic field measuring method are obtained in which a magnetic field corresponding to the magnetic field to be measured is efficiently applied to a magnetic resonance component by a flux transformer, and the magnetic resonance component, high-frequency generator, and magnet are easily arranged relative to the direction of the magnetic flux of the flux transformer, making it easy to secure space for irradiating laser light. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a block diagram showing a configuration of a magnetic field measuring device according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view showing an example of the configuration of an optical system in the magnetic sensor unit 10 shown in FIG. [Diagram 3] FIG. 3 is a cross-sectional view showing the primary coil 4a of the transformer 4. As shown in FIG. [Figure 4] FIG. 4 is a perspective view showing a configuration example of the magnetic sensor unit 10 in the magnetic field measuring device shown in FIG. [Diagram 5] FIG. 5 is a cross-sectional view (on the YZ plane) showing the arrangement of the magnetic resonance member 1, the high-frequency magnetic field generator 2, the secondary coil 4b, and the like in the magnetic sensor unit 10 shown in FIG. [Figure 6] FIG. 6 is a cross-sectional view (on the XZ plane) showing the arrangement of the magnetic resonance member 1, the high-frequency magnetic field generator 2, the secondary coil 4b, and the like in the magnetic sensor unit 10 shown in FIG. [Figure 7] FIG. 7 is a diagram (1 / 2) for explaining an example of the magnetic flux density characteristics in the magnetic resonance member 1 by the magnet 3 in FIG. [Figure 8] FIG. 8 is a diagram (2 / 2) for explaining an example of the magnetic flux density characteristics in the magnetic resonance member 1 by the magnet 3 in FIG. [Figure 9] FIG. 9 is a diagram showing the operation of the magnetic field measuring device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0013] Fig. 1 is a block diagram showing the configuration of a magnetic field measuring device according to an embodiment of the present invention. The magnetic field measuring device shown in Fig. 1 includes a magnetic sensor unit 10, a high-frequency power supply 11, an irradiation device 12, a light receiving device 13, and a calculation processing device 14.

[0014] The magnetic sensor unit 10 detects a magnetic field to be measured (e.g., the strength and direction of the magnetic field) at a predetermined position (e.g., on or above the surface of an object to be inspected). The magnetic field to be measured may be an alternating magnetic field of a single frequency, or an alternating magnetic field of a predetermined period having multiple frequency components.

[0015] In this embodiment, the magnetic sensor section 10 comprises a magnetic resonance member 1 , a high-frequency magnetic field generator 2 , a magnet 3 , and a flux transformer 4 .

[0016] The magnetic resonance member 1 has a crystal structure and is capable of quantum manipulation of electron spins (based on Rabi oscillations) using microwaves with a frequency that corresponds to the arrangement direction of defects and impurities in the crystal lattice.

[0017] In this embodiment, the magnetic resonance component 1 is a light-detecting magnetic resonance component having a plurality (i.e., an ensemble) of specific color centers. The specific color centers have energy levels that can be Zeeman split, and can take a plurality of orientations in which the energy level shift widths during Zeeman splitting are different from one another.

[0018] Here, the magnetic resonance member 1 is a member such as diamond that contains multiple NV (Nitrogen Vacancy) centers as a single type of specific color center. In the case of the NV center, the ground state is a triplet state of ms=0, +1, -1, and the level of ms=+1 and the level of ms=-1 are Zeeman split. Note that the color center contained in the magnetic resonance member 1 may be a color center other than the NV center.

[0019] The high frequency magnetic field generator 2 applies the above-mentioned microwaves to the magnetic resonance member 1. Here, the high frequency magnetic field generator 2 is a plate-shaped coil, and includes a substantially circular coil portion 2a that emits microwaves, and terminal portions 2b that extend from both ends of the coil portion 2a and are fixed to the substrate 31. The high frequency power source 11 generates a current of the microwaves and conducts it to the high frequency magnetic field generator 2.

[0020] The coil section 2a of the high frequency magnetic field generator 2 conducts two parallel currents at a predetermined interval at both end surfaces of the coil section 2a so as to sandwich the magnetic resonance component 1, and emits the microwaves described above. Here, the high frequency magnetic field generator 2 is a plate-shaped coil, but due to the skin effect, the microwave current flows through the end surfaces of the coil section 2a, so two currents are formed.

[0021] FIG. 2 is a cross-sectional view showing an example of the configuration of the optical system in the magnetic sensor unit 10 shown in FIG. 1. For example, as shown in FIG. 2, an opening 2c is formed on the side of the substantially circular and plate-shaped coil unit in the high-frequency magnetic field generator 2, and the excitation light and the measurement light from the irradiation device 12 pass through this opening 2c and are irradiated onto the magnetic resonance member 1 (the whole area or a part of the area of ​​the magnetic resonance member 1). The size of the opening 2c is determined by the size of the irradiation area in the magnetic resonance member 1 and the size of the area where the current flows under the skin effect. In this embodiment, the irradiation area in the magnetic resonance member 1 is rectangular or circular, and the plate-shaped coil of the high-frequency magnetic field generator 2 is substantially circular, so that the opening 2c is an arc-shaped rectangle, and the opening 2c is designed so that the area of ​​the projection area of ​​the opening 2c onto the magnetic resonance member 1 is larger than the area of ​​the irradiation area, and the projection area includes the irradiation area.

[0022] Moreover, the magnet 3 applies a static magnetic field (DC magnetic field) to the magnetic resonance member 1, and Zeeman-splits the energy levels of a plurality of specific color centers (here, a plurality of NV centers) in the magnetic resonance member 1. Here, the magnet 3 is a ring-shaped permanent magnet, such as a ferrite magnet, an alnico magnet, or a samarium-cobalt magnet.

[0023] In the case of NV centers, color centers are formed in diamond crystals by defects (vacancies) (V) and nitrogen (N) as impurities, and there are four possible positions of adjacent nitrogen (N) relative to the defects (vacancies) (V) in the diamond crystal (i.e., the arrangement direction of pairs of vacancies and nitrogen), and the sublevels (i.e., the energy levels from the ground level) after Zeeman splitting corresponding to each of these arrangement directions are different from each other. Therefore, in the characteristics of the fluorescence intensity after Zeeman splitting by the static magnetic field with respect to the microwave frequency, four different dip frequency pairs (fi+, fi-) appear corresponding to each direction i (i=1,2,3,4). Here, the frequency (wavelength) of the microwave described above is set corresponding to one of the dip frequencies among these four dip frequency pairs.

[0024] The flux transformer 4 includes a primary coil 4a and a secondary coil 4b electrically connected to the primary coil 4a by a cable (coaxial cable, Litz wire, etc.). As shown in FIG. 3, the primary coil 4a is configured with a winding of 0.5 to several tens of turns. The primary coil 4a senses a magnetic field to be measured at a predetermined measurement position, and the secondary coil 4b applies an applied magnetic field (magnetic field transmitted from the measurement position by the flux transformer 4) corresponding to the magnetic field to be measured sensed at the measurement position to the magnetic resonance member 1. That is, the primary coil 4a induces an electric signal corresponding to the sensed magnetic field to be measured, and the secondary coil 4b induces an applied magnetic field corresponding to the electric signal.

[0025] Fig. 4 is a perspective view showing a configuration example of the magnetic sensor unit 10 in the magnetic field measuring device shown in Fig. 1. Fig. 5 is a cross-sectional view (on the YZ plane) showing the arrangement of the magnetic resonance member 1, the high-frequency magnetic field generator 2, the secondary coil 4b, etc. in the magnetic sensor unit 10 shown in Fig. 4. Fig. 6 is a cross-sectional view (on the XZ plane) showing the arrangement of the magnetic resonance member 1, the high-frequency magnetic field generator 2, the secondary coil 4b, etc. in the magnetic sensor unit 10 shown in Fig. 4.

[0026] For example, as shown in FIGS. 4 to 6, the above-mentioned magnetic resonance component 1 is disposed at a position in which it is located in the hollow portion of the secondary coil 4b of the flux transformer 4 and also in the hollow portion of the magnet 3. As shown in FIG.

[0027] In this embodiment, the secondary coil 4b is disposed in the hollow portion of the magnet 3. Specifically, the magnet 3 is a ring-shaped magnet, and the secondary coil 4b is wound evenly in a ring shape, and is disposed within a central area of ​​radius = (radius of cross section x a%) from the center point in each cross section perpendicular to the central axis of the magnet 3 and the central axis of the secondary coil 4b. In particular, it is preferable that the magnetic resonance member 1 is disposed at the center point. Here, a is 30 or less, more preferably 20 or less, even more preferably 10 or less, and even more preferably 5 or less.

[0028] Therefore, in this embodiment, the direction of application of the above-mentioned applied magnetic field is the same as the direction of application of the above-mentioned static magnetic field, and application of the above-mentioned static magnetic field enhances the change in fluorescence intensity at the above-mentioned dip frequency, thereby increasing sensitivity.

[0029] In this embodiment, the secondary coil 4b is wound around a cylindrical non-magnetic bobbin 4b1 at a predetermined turns ratio with respect to the primary coil 4a. The bobbin 4b1 is formed with a hollow portion 4b2 (i.e., the hollow portion of the secondary coil 4b) and slits 4b3 for drawing out the winding.

[0030] Furthermore, in this embodiment, the magnetic resonance member 1 includes a plurality of color centers (here, NV centers) capable of quantum manipulation of electron spins by the above-mentioned microwaves, and the magnet 3 applies a substantially uniform static magnetic field to a predetermined region (irradiation region of the excitation light and the measurement light) of the magnetic resonance member 1. For example, the static magnetic field is applied so that the difference or ratio between the maximum and minimum values ​​of the intensity of the static magnetic field in the predetermined region is equal to or less than a predetermined value.

[0031] Furthermore, in the direction of the central axis of the magnet 3, the magnetic resonance member 1 is disposed in the central region of the width of the ring-shaped magnet 3. The "central region" here refers to a space of ±(1 / 2×b%) of the central axis of the ring-shaped magnet 3 along the Z direction (axial direction) shown in FIG. 6 from the central point of the central axis of the ring-shaped magnet 3. Here, b is 30 or less, more preferably 20 or less, even more preferably 10 or less, and even more preferably 5 or less. In this embodiment, the magnetic resonance member 1 is disposed in the center of the width of the ring-shaped magnet 3 (that is, the magnetic resonance member 1 is disposed at a position approximately equidistant from both end faces of the magnet 3). Furthermore, in the direction of the central axis of the secondary coil 4b of the transformer 4, the magnetic resonance member 1 is disposed in the central region of the width of the secondary coil 4b. The "central region" here refers to a space of ±(1 / 2×c%) of the central axis of the secondary coil 4b along the Z direction (axial direction) shown in FIG. 6 from the central point of the central axis of the secondary coil 4b. Here, c is 30 or less, more preferably 20 or less, even more preferably 10 or less, and even more preferably 5 or less. In this embodiment, the magnet 3 is disposed at the center of the width of the secondary coil 4b (that is, the magnetic resonance member 1 is disposed at a position approximately equidistant from both end faces of the secondary coil 4b). Furthermore, in a plane perpendicular to the central axis of the hollow part of the magnet 3, the cross-sectional area of ​​the hollow part is preferably 100 times or more the area of ​​the irradiation area of ​​the excitation light and the measurement light in the magnetic resonance member 1, and particularly, in the cross section of the hollow part, the diameter length is preferably 10 times or more the diameter of the irradiation area of ​​the measurement light in the radial direction. In this embodiment, the irradiation area of ​​the measurement light is 50 μm×100 μm, and the cross-sectional area of ​​the hollow part is 500 μm×1000 μm or more. In this way, a uniform static magnetic field (a static magnetic field with approximately constant direction and strength) is applied to the irradiation area of ​​the excitation light and the measurement light.

[0032] 7 and 8 are diagrams for explaining an example of the magnetic flux density characteristics in the magnetic resonance member 1 by the magnet 3 (ring-shaped magnet) in FIG. 4. The magnetic flux density characteristics shown in FIG. 7 and FIG. 8 show index #1 (the ratio between the maximum value and the average value of the magnetic flux density intensity in the above-mentioned region) and index #2 (the ratio between the minimum value and the average value of the magnetic flux density intensity in the above-mentioned region) when the outer diameter and height of the magnet 3 are changed in a case where the dimensions of the magnetic resonance member 1 are 2 mm×2 mm×1 mm, and the magnet 3 is a ferrite magnet with a residual magnetic flux density of 385 mT, a relative permeability of 1.15, and an inner diameter of 30 mm, and were obtained by simulation. As shown in FIG. 7 and FIG. 8, by appropriately setting the outer diameter and height (thickness) of the magnet 3, the variation in the magnetic flux density in the magnetic resonance member 1 can be reduced to approximately 0.5% or less.

[0033] Furthermore, the crystals of the magnetic resonance member 1 are formed and the orientation of the magnetic resonance member 1 is set so that the arrangement direction of the above-mentioned defects and impurities approximately coincides with the direction of the above-mentioned static magnetic field (and the direction of the applied magnetic field) in the magnetic resonance member 1. For example, the angle (absolute value) between the arrangement direction of the above-mentioned defects and impurities and the direction of the above-mentioned static magnetic field (and the direction of the applied magnetic field) is preferably 8 degrees or less, and most preferably 0 degree.

[0034] In this embodiment, as shown in, for example, Figs. 4 to 6, the high frequency magnetic field generator 2 is fixed to one end of an L-shaped circuit board 31, and a connector 32 electrically connected to a high frequency power source 11 by a cable is fixed to the other end of the circuit board 31. The connector 32 is electrically connected to both ends (terminal parts 2b) of the high frequency magnetic field generator 2 via the wiring pattern on the circuit board 31, electrical elements (resistors, capacitors, etc.) for impedance matching, via holes, etc. From the viewpoint of miniaturization of the entire device, a semiconductor substrate such as a SiC substrate having high insulating performance may be used for the circuit board 31. The magnetic resonance member 1 is disposed approximately at the center of the hollow part of the high frequency magnetic field generator 2. As a result, microwaves of approximately uniform intensity and direction are applied to the magnetic resonance member 1.

[0035] Furthermore, in this embodiment, an irradiation device 12 and a light receiving device 13 are provided as detection devices for detecting a physical phenomenon (here, fluorescence) corresponding to the above-mentioned applied magnetic field from the magnetic resonance component 1.

[0036] The irradiation device 12 irradiates light (excitation light of a predetermined wavelength and measurement light of a predetermined wavelength) to the magnetic resonance member 1 as a light detection magnetic resonance member through the hollow part of the secondary coil 4b along the Z direction in Fig. 6. The light receiving device 13 detects the fluorescence emitted from the magnetic resonance member 1 through the hollow part of the secondary coil 4b when the measurement light is irradiated. In this embodiment, the irradiation device 12 irradiates the magnetic resonance member 1 with the above-mentioned light along the above-mentioned central axis. As a result, the hollow part of the secondary coil 4b becomes an actual sealed space, and a space through which the optical path of the laser light (measurement light) from the irradiation device 12 and the optical path of the fluorescence from the magnetic resonance member 1 pass can be secured, and the measurement light and fluorescence do not leak into the external space.

[0037] 5 and 6, the magnetic resonance component 1 is fixed on a substantially rectangular prism 41, and the prism 41 is fixed to the bobbin 4b1 by a jig 42 so that the magnetic resonance component 1 is disposed substantially at the center of the hollow portion of the high-frequency magnetic field generator 2. As shown in Fig. 5, the prism 41 has a reflecting surface that is aligned along the X-axis direction and inclined (for example, at 45 degrees) in the YZ plane, and reflects a part of the fluorescence emitted from the magnetic resonance component 1 by this reflecting surface and emits it in the opposite direction to the excitation light and measurement light.

[0038] 2, the fluorescence is collected toward the light receiving device 13 by a compound parabolic concentrator (CPC) 43 or the like. The optical system that collects the fluorescence may have other lens configurations. In this embodiment, an opening is also formed on the side of the coil unit in the high-frequency magnetic field generator 2 that faces the compound parabolic concentrator (CPC) 43, and a part of the fluorescence emitted through this opening is also collected toward the light receiving device 13 by the compound parabolic concentrator (CPC) 43 or the like.

[0039] Although the above-mentioned physical event is optically detected here, it may be a change in an electrical characteristic (such as a change in the resistance value of the magnetic resonance component 1) or may be detected electrically.

[0040] 1, the arithmetic processing device 14 includes, for example, a computer, and executes a program on the computer to operate as various processing units. In this embodiment, the arithmetic processing device 14 stores the detected optical or electrical signal data in a storage device (such as a memory) not shown, and performs control and calculation operations as the measurement control unit 21 and the calculation unit 22.

[0041] The measurement control unit 21 controls the high-frequency power supply 11 and identifies the detection value of the above-mentioned physical phenomenon (here, the fluorescence intensity) detected by the above-mentioned detection devices (here, the irradiation device 12 and the light receiving device 13).

[0042] In this embodiment, the measurement control unit 21 controls the high frequency power supply 11 and the irradiating device 12 in accordance with a predetermined measurement sequence based on, for example, ODMR, and identifies the amount of detected fluorescence detected by the light receiving device 13. For example, the irradiating device 12 includes a laser diode or the like as a light source, and the light receiving device 13 includes a photodiode or the like as a light receiving element, and the measurement control unit 21 identifies the above-mentioned amount of detected light based on the output signal of the light receiving device 13 obtained by amplifying the output signal of the light receiving element.

[0043] The calculation unit 22 calculates the measured magnetic field (intensity, waveform, etc.) at the measurement position described above based on the detection values ​​obtained by the measurement control unit 21 and stored in the storage device.

[0044] The above-mentioned measurement sequence is set according to the frequency of the measured magnetic field. For example, when the measured magnetic field is a relatively high-frequency alternating magnetic field, a spin echo pulse sequence (such as a Hahn echo sequence) is applied to this measurement sequence. However, the measurement sequence is not limited to this. Also, for example, when the measured magnetic field is a relatively low-frequency alternating magnetic field, magnetic field measurement may be performed multiple times in one period of the measured magnetic field using a Ramsey pulse sequence (i.e., a measurement sequence of a direct current magnetic field), and the measured magnetic field (intensity, waveform, etc.) may be specified based on the results of these magnetic field measurements.

[0045] A magnetic shield is provided around the magnetic resonance member 1 in the magnetic sensor unit 10 so that an external magnetic field is not directly applied to the magnetic resonance member 1.

[0046] Next, the operation of the magnetic field measuring device according to this embodiment will be described.

[0047] 9, for example, the primary coil 4a of the flux transformer 4 in the magnetic sensor unit 10 is placed in a desired measurement position with a desired orientation relative to the measured object 101. As a result, the measured magnetic field is sensed by the primary coil 4a, and an applied magnetic field is induced by the secondary coil 4b and applied to the magnetic resonance member 1. In addition, a substantially uniform static magnetic field is applied to the magnetic resonance member 1 by the magnet 3 in the magnetic sensor unit 10.

[0048] The measurement control unit 21 then controls the high-frequency power supply 11 and the irradiation device 12 to apply microwaves and laser light (excitation light and measurement light) to the magnetic resonance component 1 at a predetermined timing and for a predetermined length of time in accordance with a predetermined measurement sequence, and obtains a detection value of a physical phenomenon of the magnetic resonance component 1 (here, the fluorescence intensity obtained by the light receiving device 13) from the magnetic sensor unit 10.The calculation unit 22 performs calculations corresponding to the measurement sequence based on the detection value, and identifies the magnetic field (strength, direction, etc.) at the measurement position.

[0049] As a result, the magnetic field at the measurement position is measured by the magnetic sensor unit 10 (i.e., the magnetic resonance member 1). Note that the magnetic sensor unit 10 may be scanned along a predetermined scanning path pattern to perform the above-mentioned magnetic field measurement at a plurality of measurement positions on the scanning path.

[0050] As described above, according to the above embodiment, the high-frequency magnetic field generator 2 applies microwaves to the magnetic resonance member 1 capable of performing electron spin quantum manipulation with microwaves. The magnet 3 applies a static magnetic field to the magnetic resonance member 1. The irradiation device 12 irradiates the magnetic resonance member 1 with light of a specific wavelength. The flux transformer 4 senses the magnetic field to be measured with the primary coil 4a, and applies an applied magnetic field corresponding to the sensed magnetic field to be measured to the magnetic resonance member 1 with the secondary coil 4b. The magnetic resonance member 1 is disposed in a position that is located in the hollow portion of the secondary coil 4b of the flux transformer 4 and also in the hollow portion of the magnet 3.

[0051] This allows a magnetic field corresponding to the magnetic field to be measured to be applied to the magnetic resonance member 1 together with a static magnetic field without interfering with the optical paths of the above-mentioned excitation light and measurement light (as well as fluorescence). Therefore, the magnetic field corresponding to the magnetic field to be measured can be efficiently applied to the magnetic resonance member 1 by the flux transformer 4 to perform magnetic field measurement. In addition, it becomes easier to arrange the magnetic resonance member 1, the high-frequency generator 2, and the magnet 3 relative to the direction of the magnetic flux of the flux transformer 4, and further makes it easier to secure a space for irradiating the laser light.

[0052] Next, a method for manufacturing the magnetic field measuring device according to this embodiment will be described.

[0053] First, the magnetic resonance member 1, the high-frequency magnetic field generator 2, the magnet 3, and the flux transformer 4 are prepared.

[0054] Next, the radio frequency generator 2 is attached to the circuit board 31. Furthermore, when a semiconductor substrate such as SiC is used from the viewpoint of miniaturization, the radio frequency generator 2 is integrally mounted on the substrate.

[0055] Next, the circuit board 31 on which the radio frequency generator 2 is attached, the magnetic resonance member 1, the prism 41, and the jig 42 are assembled together. At this time, the magnetic resonance member 1 is assembled so as to be disposed at the center of the radio frequency generator 2, and at the same time, one of the arrangement directions of the defects of the magnetic resonance member 1 is directed toward the center of the opening 2c of the radio frequency generator 2. This makes the magnetic flux generated from the radio frequency generator 2 perpendicular to at least one outer surface of the magnetic resonance member 1.

[0056] Furthermore, an assembly consisting of the radio frequency generator 2, the circuit board 31, the magnetic resonance member 1, the prism 41, and the jig 42 is inserted into the hollow part of the secondary coil 4b of the flux transformer 4 and fixed. At this time, the magnetic resonance member 1 is arranged in the central area and central region of the secondary coil 4b. In addition, the center point of the opening 2c of the radio frequency generator 2 is also arranged in the central area and central region of the secondary coil 4b. In addition, the orientation and position of each part are adjusted so that the magnetic flux generated from the radio frequency generator 2 and the magnetic flux generated from the secondary coil 4b are perpendicular to each other.

[0057] Furthermore, a magnet 3 is attached to the outside of the secondary coil 4b of the transformer 4. In addition, an irradiation device 12 is separately installed and fixed.

[0058] Alternatively, the flux transformer 4 and the magnet 3 may be first assembled so that their central axes coincide, and then they may be attached to an assembly consisting of the high-frequency generator 2, the circuit board 31, the magnetic resonance component 1, the prism 41, and the jig 42.

[0059] The above manufacturing method allows the magnetic resonance component 1, the high-frequency generator 2, and the magnet 3, and the magnetic flux direction of the flux transformer 4 to be adjusted in stages, making them easier to arrange relative to one another and eliminating the need for complicated adjustments after assembly.

[0060] It should be noted that various changes and modifications to the above-described embodiments will be apparent to those skilled in the art. Such changes and modifications may be made without departing from the spirit and scope of the subject matter and without diminishing its intended advantages. In other words, such changes and modifications are intended to be included within the scope of the claims.

[0061] For example, in the above embodiment, the secondary coil 4b is disposed in the hollow portion of the magnet 3, but the magnet 3 may be disposed in the hollow portion of the secondary coil 4b.

[0062] In the above embodiment, the thickness of the magnet 3 serving as a ring-shaped magnet may be the same as the thickness of the secondary coil 4b (or the bobbin 4b1).

[0063] Furthermore, in the above embodiment, the magnet 3 may be an electromagnet. [Industrial Applicability]

[0064] The present invention is applicable to, for example, a magnetic field measuring device and a magnetic field measuring method. [Explanation of symbols]

[0065] 1 Magnetic resonance components 2. High frequency magnetic field generator 3. Magnets 4 Flux Transformers 4a Primary coil 4b Secondary coil 11 High frequency power supply 12 Irradiation device

Claims

1. A magnetic resonance component capable of quantum manipulation of electron spins using microwaves; a high frequency magnetic field generator for applying the microwave to the magnetic resonance member; a magnet for applying a static magnetic field to the magnetic resonance member; an irradiation device for irradiating the magnetic resonance member with light of a specific wavelength; a flux transformer that senses a magnetic field to be measured by a primary coil and applies an applied magnetic field corresponding to the sensed magnetic field to the magnetic resonance member by a secondary coil; the high-frequency magnetic field generator is disposed in a hollow portion of the secondary coil of the flux transformer, the magnetic resonance member is disposed in a position that is in a hollow portion of the secondary coil and in a hollow portion of the magnet, The direction in which the secondary coil penetrates the hollow portion of the magnet is the same as the direction in which the magnet penetrates the hollow portion of the secondary coil. the irradiation device irradiates the magnetic resonance member with the light through an opening between two currents that are conducted to emit the microwaves in the high frequency magnetic field generator, such that an irradiation direction of the light with respect to the magnetic resonance member coincides with a penetration direction of a hollow part of the secondary coil and a penetration direction of a hollow part of the magnet; A magnetic field measuring device comprising:

2. The magnet is a ring magnet, The secondary coil is wound in a ring shape, The central axis of the magnet and the central axis of the secondary coil are aligned with each other, the magnetic resonance member is disposed on the central axis; 2. The magnetic field measuring device according to claim 1,

3. 3. The magnetic field measuring device according to claim 2, wherein the magnetic resonance member is disposed at the center of the width of the ring magnet in the direction of the central axis.

4. 4. The magnetic field measuring device according to claim 2, wherein the irradiation device irradiates the light to the magnetic resonance member along the central axis.

5. 5. The magnetic field measuring device according to claim 1, wherein the magnetic resonance member includes a plurality of color centers capable of quantum manipulation of electron spins by the microwave.

6. (a) sensing a magnetic field to be measured with a primary coil of a flux transformer; (b) applying an applied magnetic field corresponding to the sensed magnetic field to a magnetic resonance member capable of electron spin quantum manipulation with microwaves, with a secondary coil of the flux transformer; applying the microwaves to the magnetic resonance member; applying a static magnetic field to the magnetic resonance member; Irradiating the magnetic resonance member with light of a specific wavelength; a high-frequency magnetic field generator that applies the microwave to the magnetic resonance member is disposed in a hollow portion of the secondary coil of the flux transformer; the magnetic resonance member is disposed in a hollow portion of the secondary coil and in a hollow portion of a magnet that applies the static magnetic field to the magnetic resonance member; The direction in which the secondary coil penetrates the hollow portion of the magnet is the same as the direction in which the magnet penetrates the hollow portion of the secondary coil. irradiating the magnetic resonance member with the light through an opening between two currents that are conducted to emit the microwaves in the high frequency magnetic field generator, so that the irradiation direction of the light with respect to the magnetic resonance member coincides with the penetration direction of the hollow part of the secondary coil and the penetration direction of the hollow part of the magnet. A magnetic field measuring method comprising:

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