Magnetic field measuring device

Abstract

To efficiently apply a magnetic field corresponding to a measured magnetic field to a magnetic resonance member by a flux transformer (FT) for magnetic field measurement.SOLUTION: In a magnetic resonance member 1, a magnetostatic field is applied by a magnet 3, and a microwave is applied by a high-frequency magnetic resonance generator 2. A FT 4 senses the measured magnetic field by a primary-side coil 4a and applies the applied magnetic field corresponding to the sensed measured magnetic field to the magnetic resonance member 1 by a secondary-side coil 4b. A light guide member 41 guides incidence light of a specific wavelength to the magnetic resonance member 1, and a light guide member 42 guides fluorescence the magnetic resonance member 1 emits from the magnetic resonance member 1. The magnetic resonance member 1 is arranged with the magnetic resonance member held between an end face of the light guide member 41 and an end face of the light guide member 42 in a hollow part of the secondary-side coil 4b of the FT 4 and in a hollow part of the magnetic 3. Moreover, the secondary-side coil 4b is a bobbin-less coil.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a magnetic field measuring device.

Background Art

[0002] A certain magnetic field measuring device performs magnetic measurement by optically detected magnetic resonance (ODMR) using electron spin resonance of a sensing member such as a diamond structure having nitrogen and lattice defects (NV center: Nitrogen Vacancy Center) (see, for example, Patent Document 1). In ODMR, a static magnetic field is applied to a magnetic resonance member such as a diamond having such an NV center separately from 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 fluorescence 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 irradiated on the NV center, (b) the first π / 2 pulse of the microwave is applied to the NV center, (c) the second π / 2 pulse of the microwave is applied to the NV center at a predetermined time interval tt from the first π / 2 pulse, (d) measurement light is irradiated on the NV center to measure the light emission amount of the NV center, and (e) the magnetic flux density is derived based on the measured light emission amount. In the spin echo pulse sequence, (a) excitation light is irradiated on the NV center, (b) the first π / 2 pulse of the microwave is applied to the NV center at a phase of 0 degrees of the magnetic field to be measured, (c) the π pulse of the microwave is applied to the NV center at a phase of 180 degrees of the magnetic field to be measured, (d) the second π / 2 pulse of the microwave is applied to the NV center at a phase of 360 degrees of the magnetic field to be measured, (e) measurement light is irradiated on the NV center to measure the light emission amount of the NV center, and (f) the magnetic flux density is derived based on the measured light emission amount.

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

[0005] [Patent Document 1] Japanese Patent Publication No. 2020-8298 [Patent Document 2] Japanese Patent Application Publication No. 8-75834 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] The magnetic field measuring device described above applies laser light, microwaves, and a static magnetic field to the magnetic resonance member in addition to the magnetic field to be measured. Therefore, means for applying laser light, microwaves, and a static magnetic field, respectively, are implemented around the magnetic resonance member. Consequently, when applying laser light, microwaves, and a static magnetic field to the magnetic resonance member, using a flux transformer requires arranging the secondary coil of the flux transformer without interfering with the application of the laser light, microwaves, and static magnetic field. Geometrically, it is difficult to efficiently apply a magnetic field corresponding to the magnetic field to be measured to the magnetic resonance member using a flux transformer.

[0007] The present invention has been made in view of the above problems, and aims to provide a magnetic field measuring device that efficiently applies a magnetic field corresponding to the magnetic field to be measured to a magnetic resonance member using a flux transformer, and that facilitates the relative arrangement of the magnetic resonance member, high-frequency magnetic field generator, magnet and the direction of the magnetic flux of the flux transformer, and that facilitates the securing of space for irradiating with laser light. [Means for solving the problem]

[0008] The magnetic field measuring device according to the present invention comprises a magnetic resonance member capable of quantum manipulation of electron spins with microwaves, a high-frequency magnetic field generator that applies microwaves to the magnetic resonance member, a magnet that applies a static magnetic field to the magnetic resonance member, an irradiation device that irradiates the magnetic resonance member with incident light of a specific wavelength, a flux transformer that senses the magnetic field to be measured with a primary coil and applies an applied magnetic field corresponding to the sensed magnetic field to be measured to the magnetic resonance member with a secondary coil, a columnar first light guide member that guides the incident light to the magnetic resonance member, and a columnar second light guide member that guides the fluorescence emitted by the magnetic resonance member away from the magnetic resonance member. The magnetic resonance member is positioned between the end face of the first light guide member and the end face of the second light guide member in the hollow portion of the secondary coil of the flux transformer and the hollow portion of the magnet, and the secondary coil is a bobbinless coil. [Effects of the Invention]

[0009] According to the present invention, a magnetic field measuring device is obtained in which a flux transformer efficiently applies a magnetic field corresponding to the magnetic field to be measured to a magnetic resonance member, and in which the relative orientation of the magnetic resonance member, high-frequency magnetic field generator, magnet and flux transformer is easily arranged, and a space for irradiating laser light is easily secured. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 is a block diagram showing the configuration of a magnetic field measuring device according to an embodiment of the present invention. [Figure 2] Figure 2 is a cross-sectional view showing the primary coil of the transformer in Figure 1. [Figure 3] Figure 3 illustrates the arrangement of the primary coil of the transformer during magnetic field measurement. [Figure 4] Figure 4 is a perspective view showing an example of the configuration of a part of the magnetic sensor section shown in Figure 1. [Figure 5] Figure 5 is a side view showing an example of the optical system configuration in the magnetic sensor section shown in Figure 1. [Figure 6] Figure 6 is a perspective view (1 / 3) showing a modified example of the magnetic sensor section (partially) shown in Figure 1. [Figure 7] Figure 7 is a perspective view (2 / 3) showing a modified example of the magnetic sensor section (partially) shown in Figure 1. [Figure 8] Figure 8 is a perspective view (3 / 3) showing a modified example of the magnetic sensor section (partially) shown in Figure 1. [Figure 9] Figure 9 is a cross-sectional view showing an example of a light guide member and a magnetic resonance member in a magnetic field measuring device according to Embodiment 2. [Figure 10] Figure 10 is a perspective view (1 / 3) showing an example of a high-frequency magnetic field generator in Embodiment 3. [Figure 11] Figure 11 is a perspective view showing an example of a high-frequency magnetic field generator in Embodiment 3 (2 / 3). [Figure 12] Figure 12 is a perspective view showing an example of a high-frequency magnetic field generator in Embodiment 3 (3 / 3). [Figure 13] Figure 13 is a perspective view (1 / 2) showing an example of a light guide member, a magnetic resonance member, and a secondary coil of a flux transformer in a magnetic field measuring device according to Embodiment 4. [Figure 14] Figure 14 is a perspective view showing an example of a light guide member, a magnetic resonance member, and a secondary coil of a flux transformer in a magnetic field measuring device according to Embodiment 4 (2 / 2). [Figure 15] Figure 15 is a perspective view showing the configuration of a part of the magnetic sensor section in the magnetic field measuring device according to Embodiment 5. [Figure 16] Figure 16 is a perspective view (1 / 2) showing an example of the secondary coil of a flux transformer in Embodiment 6. [Figure 17] Figure 17 is a perspective view showing an example of the secondary coil of a flux transformer in Embodiment 6 (2 / 2). [Figure 18] Figure 18 is a perspective view showing the configuration of a part of the magnetic sensor section in the magnetic field measuring device according to Embodiment 7. [Figure 19] FIG. 19 is a perspective view (1 / 2) showing the configuration of a magnetic sensor unit (part) in the magnetic field measurement device according to Embodiment 8. [Figure 20] FIG. 20 is a perspective view (2 / 2) showing the configuration of a magnetic sensor unit (part) in the magnetic field measurement device according to Embodiment 8. [Figure 21] FIG. 21 is a perspective view showing the configuration of a magnetic sensor unit (part) in the magnetic field measurement device according to Embodiment 9. [Figure 22] FIG. 22 is a cross-sectional view showing the configuration of a magnetic sensor unit (part) in the magnetic field measurement device according to Embodiment 9. [Figure 23] FIG. 23 is a perspective view showing the configuration of a magnetic sensor unit (part) in the magnetic field measurement device according to Embodiment 10. [Figure 24] FIG. 24 is a cross-sectional view showing the configuration of a magnetic sensor unit (part) in the magnetic field measurement device according to Embodiment 10.

DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present invention will be described based on the drawings.

[0012] Embodiment 1.

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

[0014] The magnetic sensor unit 10 detects a magnetic field to be measured (for example, the intensity and direction of the magnetic field) at a predetermined position (for example, on or above the surface of the inspection target object). 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 a plurality of frequency components.

[0015] In this embodiment, the magnetic sensor unit 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 crystalline structure and is a member capable of quantum manipulation of electron spin (based on Rabi oscillations) using microwaves of a frequency corresponding to the alignment direction of defects and impurities in the crystal lattice.

[0017] In this embodiment, the magnetic resonance member 1 is a photodetector magnetic resonance member having a plurality (i.e., an ensemble) of specific color centers. These specific color centers have energy levels that can be Zeeman split, and can take on multiple orientations in which the shift width of the energy levels during Zeeman splitting is different from that of the others.

[0018] Here, the magnetic resonance member 1 is a material such as diamond containing multiple NV (Nitrogen Vacancy) centers as a single type of specific color center. In the case of NV centers, the ground state is a triplet state with ms=0,+1,-1, and the levels at ms=+1 and ms=-1 undergo Zeeman splitting. Note that the color centers included in the magnetic resonance member 1 may be color centers other than NV centers.

[0019] The high-frequency magnetic field generator 2 applies the aforementioned microwaves to the magnetic resonance member 1.

[0020] Furthermore, magnet 3 applies a static magnetic field (DC magnetic field) to the magnetic resonance member 1. Here, magnet 3 is a ring-shaped permanent magnet, such as a ferrite magnet, alnico magnet, or samarium-cobalt magnet.

[0021] The magnetic resonance member 1 is equipped with multiple color centers (in this case, NV centers) capable of electron spin quantum manipulation using the microwaves described above. The magnet 3 applies a substantially uniform static magnetic field to a predetermined region of the magnetic resonance member 1 (the irradiation region of the excitation light and measurement light), causing Zeeman splitting of the energy levels of multiple specific color centers (in this case, multiple NV centers) within the magnetic resonance member 1. For example, the static magnetic field is applied such that the difference or ratio between the maximum and minimum values ​​of the static magnetic field strength in that predetermined region is less than or equal to a predetermined value.

[0022] In the case of NV centers, color centers are formed in a diamond crystal by defects (vacancies) (V) and nitrogen (N) as impurities. There are four possible positions for adjacent nitrogen (N) atoms relative to a defect (vacancy) (V) in the diamond crystal (i.e., the alignment direction of pairs of vacancies and nitrogen atoms), and the sub-levels after Zeeman splitting (i.e., energy levels from the ground) corresponding to each of these alignment directions are all different. Therefore, in the characteristics of fluorescence intensity after Zeeman splitting due to a static magnetic field with respect to microwave frequency, four distinct dip frequency pairs (fi+, fi-) appear, corresponding to each direction i (i=1,2,3,4). Here, the microwave frequency (wavelength) is set corresponding to one of these four dip frequency pairs.

[0023] Furthermore, the flux transformer 4 comprises 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 Figure 2, the primary coil 4a is composed of windings of 0.5 to several tens of turns. Also, as shown in Figure 3, the primary coil 4a senses the magnetic field to be measured at a predetermined measurement position above the object to be measured 101, for example, 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 that measurement position to the magnetic resonance member 1. In other words, the primary coil 4a induces an electrical signal corresponding to the sensed magnetic field to be measured, and the secondary coil 4b induces an applied magnetic field corresponding to that electrical signal.

[0024] Furthermore, an irradiation device 12 and a light receiving device 13 are provided as detection devices for detecting fluorescence generated from the magnetic resonance member 1 by physical events corresponding to the applied magnetic field described above.

[0025] The irradiation device 12 generates laser light to be irradiated onto the magnetic resonance member 1 (in this case, excitation light of a predetermined wavelength for ODMR and measurement light of a predetermined wavelength) and irradiates the magnetic resonance member 1, which serves as a photodetector magnetic resonance member, via the optical system described later.

[0026] Furthermore, the light receiving device 13 detects the fluorescence emitted from the magnetic resonance member 1 via the optical system described later when the measurement light is irradiated.

[0027] The arithmetic processing unit 14, for example, is equipped with a computer and executes programs on the computer to operate as various processing units. In this embodiment, the arithmetic processing unit 14 stores the detected optical or electrical signal data in a storage device (such as memory) not shown, and performs control and calculation operations as the measurement control unit 21 and the calculation unit 22.

[0028] The measurement control unit 21 controls the high-frequency power supply 11 and identifies the detected value of the physical event (in this case, fluorescence intensity) detected by the detection device (in this case, the irradiation device 12 and the light receiving device 13).

[0029] In this embodiment, the measurement control unit 21 controls the high-frequency power supply 11 and the irradiation device 12 according to a predetermined measurement sequence, for example based on ODMR, and determines the amount of detected light from the fluorescence detected by the light receiving device 13. For example, the irradiation device 12 is equipped with a laser diode or the like as a light source, and the light receiving device 13 is equipped with a photodiode or the like as a light receiving element, and the measurement control unit 21 determines 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.

[0030] The calculation unit 22 calculates the magnetic field to be measured (intensity, waveform, etc.) at the measurement position based on the detected values ​​obtained by the measurement control unit 21 and stored in the memory.

[0031] The measurement sequence described above is set according to the frequency of the magnetic field being measured. For example, if the magnetic field being measured is a relatively high-frequency AC 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, if the magnetic field being measured is a relatively low-frequency AC magnetic field, the magnetic field may be measured multiple times using a Ramsay pulse sequence (i.e., a DC magnetic field measurement sequence) during one period of the magnetic field being measured, and the magnetic field being measured (intensity, waveform, etc.) may be identified based on the results of these magnetic field measurements.

[0032] The details of the magnetic sensor unit 10 will be described below.

[0033] Figure 4 is a perspective view showing an example configuration of a part of the magnetic sensor unit 10 shown in Figure 1. Figure 5 is a side view showing an example configuration of the optical system in the magnetic sensor unit 10 shown in Figure 1.

[0034] In this embodiment, as shown in Figures 4 and 5, for example, the high-frequency magnetic field generator 2 is a plate-shaped coil comprising a substantially circular coil portion 2a that emits microwaves into its hollow portion, and terminal portions 2b extending from both ends of the coil portion 2a and fixed to a substrate or the like (not shown). The high-frequency power supply 11 generates a high-frequency current of microwaves and conducts it to the high-frequency magnetic field generator 2. The coil portion 2a of the high-frequency magnetic field generator 2 conducts two parallel currents at a predetermined interval between its end face portions 2a-1 and 2a-2, sandwiching the magnetic resonance member 1, thereby emitting the microwaves described above. Here, although the high-frequency magnetic field generator 2 is a plate-shaped coil, due to the skin effect, the microwave current flows through the end face portions 2a-1 and 2a-2 of the coil portion 2a, thus forming two currents. As a result, microwaves of substantially uniform intensity are applied to the magnetic resonance member 1.

[0035] Furthermore, as shown in Figures 4 and 5, the magnetic sensor unit 10 also includes light guide members 41 and 42.

[0036] The light guide member 41 is a light-transmitting columnar (in this case, rectangular columnar) member that guides incident light from the irradiation device 12 to the magnetic resonance member 1. The light guide member 42 is a light-transmitting columnar (in this case, rectangular columnar) member that guides the fluorescence emitted by the magnetic resonance member 1 from the magnetic resonance member 1 toward the light receiving device 13. The light guide members 41 and 42 are, for example, made of glass and have the same cross-section in a direction perpendicular to the longitudinal direction.

[0037] Furthermore, the magnetic resonance member 1 is positioned between the end face of the light guide member 41 and the end face of the light guide member 42 in the hollow portion of the secondary coil 4b of the flux transformer 4 and the hollow portion of the magnet 3.

[0038] Specifically, the magnetic resonance member 1 has, for example, a roughly rectangular parallelepiped plate shape, and one of the two opposing surfaces of the magnetic resonance member 1 is in surface contact with the end face of the light guide member 41 or surface-bonded (for example with adhesive), and the other surface is in surface contact with the end face of the light guide member 42 or surface-bonded (for example with adhesive). As a result, the light guide members 41, 42 and the magnetic resonance member 1 are arranged in a straight line.

[0039] The secondary coil 4b is a bobbinless coil and is fixed to the outer circumference of the secondary coil 4b by support members (not shown) and filling members (described later) such that the central axis of the secondary coil 4b substantially coincides with the centers of the light guide members 41, 42 and the magnetic resonance member 1, and is substantially perpendicular to the central axis of the coil section 2a of the high-frequency magnetic field generator 2. The secondary coil 4b is wound in a ring shape (here, annular) with a predetermined turns ratio relative to the primary coil 4a, and is positioned in the hollow part of the substantially circular and plate-shaped coil section 2a of the high-frequency magnetic field generator 2, for example, as shown in Figures 4 and 5. When the secondary coil 4b is made of thin wire and has many turns, in order to prevent the coil wire from unraveling, a bobbinless secondary coil 4b is formed by, for example, using self-fusing wire for the coil wire, or by winding the coil wire around a bobbin jig, coating it with adhesive, and then removing the bobbin jig.

[0040] Furthermore, openings 2c and 2d are formed on the sides of the substantially circular and plate-shaped coil portion 2a in the high-frequency magnetic field generator 2. The openings 2c and 2d are located in the axial direction of the secondary coil 4b when viewed from the secondary coil 4b, and are positioned opposite each other through the center of the coil portion 2a in a direction substantially perpendicular to the central axis direction of the coil portion 2a.

[0041] As a result, the direction of the microwaves (magnetic field) from the high-frequency magnetic field generator 2 becomes approximately perpendicular to the direction of the magnetic field from the secondary coil 4b. The angle between the direction of the microwaves (magnetic field) from the high-frequency magnetic field generator 2 and the direction of the magnetic field from the secondary coil 4b is preferably in the range of 90 degrees ± 8 degrees, and most preferably 90 degrees.

[0042] The sizes of the openings 2c and 2d are determined by the size of the irradiation area in the magnetic resonance member 1 and the size of the area in the coil portion 2a where 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 approximately circular, so the openings 2c and 2d are arc-shaped rectangles, and the area of ​​the projection region of the openings 2c and 2d onto the magnetic resonance member 1 is larger than the area of ​​the irradiation area, and the openings 2c and 2d are designed so that the irradiation area is included within the projection region.

[0043] The plate-shaped magnetic resonance member 1 and the columnar light guide members 41 and 42 are then placed and fixed within the openings 2c and 2d. In other words, in Embodiment 1, the high-frequency magnetic field generator 2 includes a substantially circular and plate-shaped coil section 2a that emits microwaves, the coil section 2a has two openings 2c and 2d, the first light guide member 41 is positioned to penetrate one of the two openings 2c and 2d (opening 2c), and the second light guide member 42 is positioned to penetrate the other of the two openings 2c and 2d (opening 2d).

[0044] Furthermore, in this embodiment, as shown in Figure 4, the magnet 3 is a ring-shaped magnet, the secondary coil 4b is wound in a ring shape, the central axis of the magnet 3 and the central axis of the secondary coil 4b coincide with each other, and the magnetic resonance member 1, the light guide member 41, and the light guide member 42 are arranged on their central axes.

[0045] For example, as shown in Figure 4, the magnetic resonance member 1 described above is positioned in the hollow part of the secondary coil 4b of the flux transformer 4 and in the hollow part of the magnet 3. In this embodiment, the secondary coil 4b is located in the hollow part of the magnet 3. The magnetic resonance member 1 is positioned within the central area of ​​the radius = (radius of the cross section × 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 positioned 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.

[0046] Therefore, in this embodiment, the direction in which the magnetic field applied by the secondary coil 4b is applied is the same as the direction in which the static magnetic field applied by the magnet 3 is applied, and the application of the static magnetic field enhances the change in fluorescence intensity at the dip frequency, thereby increasing sensitivity.

[0047] Furthermore, in the magnetic resonance member 1, the crystal of the magnetic resonance member 1 is formed and its orientation is set such that the arrangement direction of the aforementioned defects and impurities substantially coincides with the direction of the static magnetic field (and the direction of the applied magnetic field) as described above.

[0048] Furthermore, the angle (absolute value) between the alignment direction of the aforementioned defects and impurities and the direction of the static magnetic field (and the direction of the applied magnetic field) is preferably 8 degrees or less, and most preferably 0 degrees.

[0049] Furthermore, in the direction of the central axis of the magnet 3, the magnetic resonance member 1 is positioned in the central region of the width of the ring-shaped magnet 3. Here, the "central region" refers to the space ±(central axis length 1 / 2 × b%) along the central axis direction from the center 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.

[0050] Furthermore, in this embodiment, the magnetic resonance member 1 is positioned at the center of the width of the ring-shaped magnet 3 (that is, the magnetic resonance member 1 is positioned at approximately equidistant distances from both end faces of the magnet 3). In addition, in the direction of the central axis of the secondary coil 4b of the transformer 4, the magnetic resonance member 1 is positioned in the central area of ​​the width of the secondary coil 4b. Here, "central area" refers to the space ±(central axis length 1 / 2 × c%) along the central axis direction from the center 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. Furthermore, in this embodiment, it is positioned at the center of the width of the secondary coil 4b (that is, the magnetic resonance member 1 is positioned at approximately equidistant distances from both end faces of the secondary coil 4b). Furthermore, in a plane perpendicular to the central axis of the hollow portion of the magnet 3, it is preferable that the cross-sectional area of ​​the hollow portion be at least 100 times the area of ​​the irradiation region of the excitation light and measurement light in the magnetic resonance member 1, and in particular, that the diameter of the cross-section of the hollow portion be at least 10 times the diameter of the irradiation region of the measurement light in the radial direction. In this embodiment, for example, if the irradiation region of the measurement light is 50 μm × 100 μm, the cross-sectional area of ​​the hollow portion will be 500 μm × 1000 μm or more. By doing so, a uniform static magnetic field (a static magnetic field with substantially constant direction and intensity) is applied to the irradiation regions of the excitation light and measurement light.

[0051] Furthermore, the fluorescence emitted by the magnetic resonance member 1 is focused from the magnetic resonance member 1 towards the light receiving device 13 via the light guide member 42 and a predetermined optical system 43, as shown in Figure 5, for example. In this embodiment, the optical system 43 includes composite parabolic condensers (CPCs) 43a and 43b, as shown in Figure 5, for example. Note that the optical system 43 may have other lens configurations. The end face of the light guide member 42 is in surface contact with or surface-bonded (for example, with an adhesive) to the end face of the CPC 43a, and the fluorescence guided by the light guide member 42 enters the interior of the CPC 43a through this end face.

[0052] This optical system 43 is designed to prevent the incident light (i.e., the residual component that has passed through the magnetic resonance member 1) from entering the photodetector 13. Specifically, as shown in Figure 5, for example, a dichroic mirror 43c that transmits the fluorescence and reflects the incident light and / or a long-pass filter 43d that transmits the fluorescence and attenuates the incident light are provided in the optical system 43. The incident light reflected by the dichroic mirror 43c is detected by a reference photodetector 13a, and the calculation unit 22 corrects the measured value of the magnetic field under measurement based on the amount of incident light detected by the reference photodetector 13a (for example, the deviation from a predetermined reference light amount).

[0053] In this embodiment, the irradiation device 12 irradiates the magnetic resonance member 1 with the incident light described above along the central axis via the light guide member 41. As a result, the incident light enters the interior of the light guide member 41 from its end face 41a, is reflected off the side surface of the light guide member 41, and travels toward the magnetic resonance member 1. In this way, the light guide member 41 ensures a space through which the laser light (measurement light) from the irradiation device 12 and the fluorescence light from the magnetic resonance member 1 can pass, preventing the measurement light and fluorescence from leaking into the outside space.

[0054] Furthermore, a magnetic shield is provided around the magnetic resonance member 1 in the magnetic sensor unit 10 to prevent external magnetic fields from being directly applied to the magnetic resonance member 1.

[0055] Figures 6 to 8 are perspective views showing modified examples of the magnetic sensor section 10 (partially) shown in Figure 1. For example, as shown in Figures 6 to 8, the secondary coil 4b may be a ring-shaped coil wound in a rectangular shape corresponding to the shapes of the light guide members 41 and 42 and the magnetic resonance member 1. Furthermore, the diameter of the substantially annular curved plate-shaped coil section 2a is not particularly limited, and the coil section 2a may be of a size as shown in Figures 6 to 8, for example.

[0056] Next, the operation of the magnetic field measuring device according to this embodiment will be described.

[0057] For example, as shown in Figure 3, the primary coil 4a of the flux transformer 4 in the magnetic sensor unit 10 is positioned at a desired measurement position and in a desired orientation relative to the object 101 to be measured. As a result, the magnetic field to be measured is sensed by the primary coil 4a, and an applied magnetic field is induced by the secondary coil 4b, which is then 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.

[0058] The measurement control unit 21 controls the high-frequency power supply 11 and the irradiation device 12 to apply microwaves from the high-frequency magnetic field generator 2 to the magnetic resonance member 1 according to a predetermined measurement sequence, and also applies laser light (excitation light and measurement light) from the irradiation device 12 to the magnetic resonance member 1 via the light guide member 41. The light receiving device 13 receives the fluorescence emitted from the magnetic resonance member 1 in response to this excitation light and measurement light via the light guide member 42 and the optical system 43, and outputs an electrical signal corresponding to the amount of fluorescence (fluorescence intensity). The measurement control unit 21 acquires this electrical signal, and the calculation unit 22 performs calculations corresponding to the measurement sequence based on the detected value of the fluorescence intensity to determine the magnetic field (intensity, direction, etc.) at the measurement location.

[0059] As a result, the magnetic sensor unit 10 (i.e., the magnetic resonance member 1) measures the magnetic field at the measurement location. Alternatively, the magnetic sensor unit 10 may be scanned along a predetermined scanning path pattern, and the above-described magnetic field measurements may be performed at multiple measurement locations along the scanning path.

[0060] As described above, according to Embodiment 1, the high-frequency magnetic field generator 2 applies microwaves to the magnetic resonance member 1, which is capable of quantum manipulation of electron spins 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 incident light of a specific wavelength. The flux transformer 4 senses the magnetic field to be measured with its 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 its secondary coil 4b. The columnar light guide member 41 guides its incident light to the magnetic resonance member 1, and the columnar light guide member 42 guides the fluorescence emitted by the magnetic resonance member 1 from the magnetic resonance member 1. The magnetic resonance member 1 is positioned sandwiched between the end face of the light guide member 41 and the end face of the light guide member 42 in the hollow part of the secondary coil 4b of the flux transformer 4 and the hollow part of the magnet 3 described above. Furthermore, the secondary coil 4b of the flux transformer 4 is a bobbinless coil.

[0061] This allows the magnetic field corresponding to the magnetic field to be measured to be applied to the magnetic resonance member 1, along with the static magnetic field, without obstructing the optical paths of the excitation light and measurement light (and fluorescence) mentioned above. Therefore, the flux transformer 4 can efficiently apply the magnetic field corresponding to the magnetic field to be measured to the magnetic resonance member 1, enabling magnetic field measurement. Furthermore, it becomes easier to relatively arrange the magnetic resonance member 1, the high-frequency magnetic field generator 2, the magnet 3, and the direction of the magnetic flux of the flux transformer 4, and it also becomes easier to secure space for irradiating with laser light.

[0062] Next, a method for manufacturing the magnetic field measuring device according to the embodiment will be described.

[0063] First, prepare the magnetic resonance member 1, the high-frequency magnetic field generator 2, the magnet 3, and the flux transformer 4.

[0064] Next, the high-frequency magnetic field generator 2 is mounted on a circuit board (not shown). Furthermore, from the standpoint of miniaturization, if a semiconductor substrate such as SiC is used, the high-frequency magnetic field generator 2 is integrated into that substrate.

[0065] Next, the high-frequency magnetic field generator 2 is fixed by fixing the circuit board, and the secondary coil 4b of the flux transformer 4 is positioned so that the open end of the secondary coil 4b faces the openings 2c and 2d of the high-frequency magnetic field generator 2, respectively. The magnetic resonance member 1 is assembled so that one of the defect alignment directions is directed toward the center of the openings 2c and 2d. As a result, the magnetic flux generated from the high-frequency magnetic field generator 2 becomes perpendicular to at least one outer surface of the magnetic resonance member 1.

[0066] Then, the light guide member 41, the magnetic resonance member 1, and the light guide member 42 are inserted through the openings 2c and 2d and fixed in place. At this time, the magnetic resonance member 1 is positioned 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 high-frequency magnetic field generator 2 and the magnetic flux generated from the secondary coil 4b are perpendicular to each other.

[0067] Furthermore, a magnet 3 is attached to the outside of the high-frequency magnetic field generator 2. In addition, the irradiation device 12, optical system 43, and light receiving device 13 are installed and fixed separately.

[0068] The above manufacturing method allows for stepwise adjustment of the magnetic resonance member 1, the high-frequency magnetic field generator 2, the magnet 3, and the direction of the magnetic flux of the flux transformer 4, making them easier to arrange relatively and eliminating the need for complicated adjustments after assembly.

[0069] Embodiment 2.

[0070] Figure 9 is a cross-sectional view showing an example of a light guide member and a magnetic resonance member in a magnetic field measuring device according to Embodiment 2. In Embodiment 2, one or both (here, both) of the light guide member 41 and the light guide member 42 are provided with recesses 45 and 46 on their end faces that correspond to the shape of the magnetic resonance member 1. The magnetic resonance member 1 is then positioned in these recesses 45 and 46.

[0071] Specifically, the magnetic resonance member 1 is positioned in these recesses 45 and 46, and the portion of the end face of the light guide member 41 other than the recess 45 and the portion of the end face of the light guide member 42 other than the recess 46 are in surface contact with each other or surface-bonded (for example with an adhesive) to fix them together.

[0072] The other configurations and operations of the magnetic field measuring device according to Embodiment 2 are the same as those of any other embodiment, so their description will be omitted.

[0073] Embodiment 3.

[0074] Figures 10 to 12 are perspective views showing an example of a high-frequency magnetic field generator 2 in Embodiment 3. In Embodiment 3, the high-frequency magnetic field generator 2 includes two coil sections a61-1 and 61a-2 instead of the coil section 2a, and terminal sections 61b-1 and 61b-2 instead of the terminal section 2b.

[0075] For example, as shown in Figure 10, the high-frequency magnetic field generator 2 comprises a substantially circular coil section 61a-1, 61-2 that emits microwaves, and terminal sections 61b-1, 61b-2 that extend from both ends of the coil sections 61a-1, 61a-2 and are fixed to a substrate or the like (not shown).

[0076] The coil sections 61a-1 and 61a-2 conduct two parallel currents (currents with substantially the same amplitude and substantially the same frequency, synchronized with each other) at a predetermined interval so as to sandwich the magnetic resonance member 1, thereby emitting the microwaves described above. As a result, microwaves of substantially uniform intensity are applied to the magnetic resonance member 1.

[0077] In Embodiment 1, the high-frequency magnetic field generator 2 is a horizontally wound (α-winding) plate-shaped coil, while in Embodiment 3, the high-frequency magnetic field generator 2 is a vertically wound (edgewise winding) plate-shaped coil.

[0078] Furthermore, at least a portion of the light guide member 41, at least a portion of the light guide member 41, and the magnetic resonance member 1 are arranged in the space between the two coil portions 61a-1 and 61a-2.

[0079] Furthermore, as shown in Figure 11, for example, in Embodiment 3, a plate-shaped member 62-1 and a plate-shaped member 62-2 arranged substantially parallel to the plate-shaped member 62-1 are provided, the coil portion 61a-1 is arranged on the surface of the plate-shaped member 62-1, and the coil portion 61a-2 is arranged on the surface of the plate-shaped member 62-2 facing the surface of the plate-shaped member 62-1.

[0080] Alternatively, plate-shaped members 62-1 and 62-2 may be used as substrates, and coil portions 61a-1 and 61a-2 may be used as wiring patterns on those substrates, respectively. Furthermore, plate-shaped members 62-1 and 62-2 may be glass substrates or fluororesin (PTEF) substrates.

[0081] Furthermore, as shown in Figure 12, for example, the terminal portion 61b-1 may be bent at the edge of the plate-shaped member 62-1 and extend from the coil portion 61a-1 along the side surface of the first plate-shaped member 62-1, and the terminal portion 61b-2 may be bent at the edge of the plate-shaped member 62-2 and extend from the coil portion 61a-2 along the side surface of the plate-shaped member 62-2.

[0082] The other configurations and operations of the magnetic field measuring device according to Embodiment 3 are the same as those of any of the other embodiments, so their description will be omitted.

[0083] Embodiment 4.

[0084] Figures 13 and 14 are perspective views showing examples of the light guide member, magnetic resonance member, and secondary coil of the flux transformer in a magnetic field measuring device according to Embodiment 4. For example, as shown in Figures 13 and 14, in Embodiment 4, the light guide members 41 and 42 have a substantially cylindrical shape. Other optical properties of the light guide members 41 and 42 in Embodiment 4 are the same as those of the light guide members 41 and 42 in Embodiment 1. Here, Figure 13 shows a modified version of the light guide members 41 and 42 shown in Figure 11, and Figure 14 shows a modified version of the light guide members 41 and 42 shown in Figure 12.

[0085] The magnetic resonance member 1 sandwiched between the light guide member 41 and the light guide member 42 may be substantially cylindrical in shape (for example, having the same diameter as the first light guide member 41). Alternatively, recesses similar to those in Embodiment 2 may be provided so that the magnetic resonance member 1 is positioned in the recesses 45 and 46.

[0086] The other configurations and operations of the magnetic field measuring device according to Embodiment 4 are the same as those of any of the other embodiments, so their description will be omitted.

[0087] Embodiment 5.

[0088] Figure 15 is a perspective view showing the configuration of a part of the magnetic sensor section in the magnetic field measuring device according to Embodiment 5. For example, as shown in Figure 15, in Embodiment 5, an optical member 71 is provided in the magnetic sensor section 10. The optical member 71 is positioned adjacent to the end face 41a of the light guide member 41 and transmits the excitation light and reflects fluorescence. Here, the end face 71a of the optical member 71 is in contact with the end face 41a of the light guide member 41.

[0089] For example, in the optical component 71, a dielectric multilayer film is formed on the end face 71a of a flat plate-shaped body such as transparent glass. This dielectric multilayer film transmits light of the wavelength of excitation light to the light guide member 41 (e.g., 533 nm) and reflects light of the wavelength of fluorescence from the light guide member 41 (e.g., 600 nm to 800 nm). As a result, fluorescence that has traveled from the magnetic resonance member 1 to the light guide member 41 is reflected by the optical component 71, travels through the light guide members 41 and 42, and is received by the light receiving device 13. Therefore, the amount of fluorescence light received by the light receiving device 13 is increased by the optical component 71.

[0090] The other configurations and operations of the magnetic field measuring device according to Embodiment 5 are the same as those of any of the other embodiments, so their description will be omitted.

[0091] Embodiment 6.

[0092] Figures 16 and 17 are perspective views showing an example of the secondary coil of the flux transformer 4 in Embodiment 6.

[0093] In Embodiment 6, for example, as shown in Figures 16 and 17, the secondary coil 4b of the flux transformer 4 is composed of two divided coils 4b-1 and 4b-2. These two divided coils 4b-1 and 4b-2 are electrically connected in series or parallel (in this case, in series). The divided coils 4b-1 and 4b-2 of the secondary coil 4b induce an applied magnetic field corresponding to the electrical signal described above.

[0094] Furthermore, as shown in Figure 17, for example, the divided coils 4b-1 and 4b-2 may be electrically connected in series, and the end 65 of the secondary coil 4b may extend in the opposite direction to the terminals 61b-1 and 61b-2 of the high-frequency magnetic field generator 2.

[0095] The other configurations and operations of the magnetic field measuring device according to Embodiment 6 are the same as those of any of the other embodiments, so their description will be omitted.

[0096] Embodiment 7.

[0097] Figure 18 is a perspective view showing the configuration of a part of the magnetic sensor section in the magnetic field measuring device according to Embodiment 7. In Embodiment 7, for example, as shown in Figure 18, a substrate 81 is provided. The substrate 81 is provided with wiring patterns 82, 83-1, and 83-2 that conduct the high-frequency microwave current described above.

[0098] On the substrate 81, plate-shaped members 62-1 and 62-2 are positioned and fixed upright relative to the substrate 81, and terminal portions 61b-1 and 61b-2 are electrically connected to the wiring patterns 82, 83-1, and 83-2 of the substrate 81 by soldering or the like.

[0099] Specifically, one end of 61b-1 and one end of 61b-2 are connected to wiring pattern 82, and the other end of 61b-1 and the other end of 61b-2 are connected to wiring patterns 83-1 and 83-2, respectively. Wiring pattern 82 is electrically connected to the high-frequency power supply 11, and wiring patterns 83-1 and 83-2 are terminated, for example, with through-holes 84-1 and 84-2. Note that the termination portions of wiring patterns 83-1 and 83-2 are not limited to the illustrated through-holes.

[0100] The other configurations and operations of the magnetic field measuring device according to Embodiment 7 are the same as those of any of the other embodiments, so their description will be omitted.

[0101] Embodiment 8.

[0102] Figures 19 and 20 are perspective views showing the configuration of a part of the magnetic sensor section in the magnetic field measuring device according to Embodiment 8. In Embodiment 8, for example, as shown in Figure 19, a substrate 91 is provided. The substrate 91 is provided with wiring patterns 92 and 93 that conduct the high-frequency microwave current described above.

[0103] On the substrate 91, plate-shaped members 62-1 and 62-2 are positioned and fixed upright relative to the substrate 81, and terminal portions 61b-1 and 61b-2 are electrically connected to the wiring patterns 92 and 93 of the substrate 91 by soldering or the like.

[0104] Specifically, one end of 61b-1 and one end of 61b-2 are connected to wiring pattern 92, and the other end of 61b-1 and the other end of 61b-2 are connected to wiring pattern 93. Wiring pattern 92 is electrically connected to the high-frequency power supply 11, and wiring pattern 93 is terminated with a through-hole 94.

[0105] Furthermore, as shown in Figure 19, for example, the end 65 of the secondary coil 4b extends in the opposite direction to the substrate 91.

[0106] Figure 20 shows a modified example of the magnetic sensor unit 10 in Embodiment 8. For example, as shown in Figure 20, the optical member 71 is fixed by a frame member 95, and the frame member 95 is fixed in contact with the side surfaces (side surfaces perpendicular to the substrate 91) of the plate-shaped members 62-1 and 62-2.

[0107] The other configurations and operations of the magnetic field measuring device according to Embodiment 8 are the same as those of any of the other embodiments, so their description will be omitted.

[0108] Embodiment 9.

[0109] Figure 21 is a perspective view showing the configuration of a part of the magnetic sensor section in the magnetic field measuring device according to Embodiment 9. Figure 22 is a cross-sectional view showing the configuration of a part of the magnetic sensor section in the magnetic field measuring device according to Embodiment 9.

[0110] The magnetic sensor section 10 shown in Figures 21 and 22 is the magnetic sensor section 10 shown in Figure 20 above, with the addition of a filling member 96. The filling member 96 is formed by filling the space between the plate-shaped member 62-1 and the plate-shaped member 62-2 (more specifically, the space surrounded by the plate-shaped member 62-1, the plate-shaped member 62-2, the substrate 91, and the frame member 95) with a curing resin (such as a thermosetting resin).

[0111] For example, as shown in Figure 20, after assembling the light guide members 41, 42, the magnetic resonance member 1, and the secondary coil 4b, and assembling the plate-shaped members 62-1, 62-2, the substrate 91, and the frame member 95, the assembly of the light guide members 41, 42, the magnetic resonance member 1, and the secondary coil 4b is placed in the aforementioned space using a jig or the like, and curing resin is injected and cured to form the filling member 96. At that time, temporary frames are placed as necessary in the open parts at the bottom of the optical member 71 and the frame member 95, and in the open parts on the opposite side of the optical member 71 and the frame member 95, to prevent the injected curing resin from flowing out, and these are removed after curing.

[0112] The other configurations and operations of the magnetic field measuring device according to Embodiment 9 are the same as those of any of the other embodiments, so their description will be omitted.

[0113] Embodiment 10.

[0114] Figure 23 is a perspective view showing the configuration of a part of the magnetic sensor section in the magnetic field measuring device according to Embodiment 10. Figure 24 is a cross-sectional view showing the configuration of a part of the magnetic sensor section in the magnetic field measuring device according to Embodiment 10.

[0115] In Embodiment 10, as shown in Figures 23 and 24, the filling member 96 is provided with an observation hole 97 for optically observing the magnetic resonance member 1 from the side opposite to the substrate 91. For example, a fiberscope is inserted into the observation hole 97, and the magnetic resonance member 1 is observed with the fiberscope. When observation is not being performed, a light-shielding member is attached to the observation hole 97 to prevent external light from entering the magnetic resonance member 1.

[0116] The other configurations and operations of the magnetic field measuring device according to Embodiment 10 are the same as those of Embodiment 9, so their description will be omitted.

[0117] Furthermore, various changes and modifications to the embodiments described above will be obvious to those skilled in the art. Such changes and modifications may be made without deviating from the spirit and scope of the subject matter and without diminishing the intended advantages. In other words, such changes and modifications are intended to be included in the claims.

[0118] For example, in any of the above embodiments, the magnet 3 may be an electromagnet.

[0119] Furthermore, in any of the above embodiments, a reflective film (such as a dielectric multilayer film) may be provided on the sides of the light guide members 41 and 42. Also, a reflective film (such as a dielectric multilayer film) may be provided on the sides of the CPCs 43a and 43b.

[0120] Furthermore, in any of the above embodiments, the light guide members 41 and 42 may have the same length. Also, the cross-sectional shape of the light guide members 41 and 42 is not limited to circular and square shapes, but may be other shapes such as hexagons. In addition, the material of the light guide members 41 and 42 may be a transparent resin such as acrylic.

[0121] Furthermore, in any of the above embodiments, the secondary coil 4b may be directly wound around at least one of the first light guide member 41, the second light guide member 42, and the magnetic resonance member 1.

[0122] Furthermore, in any of the above embodiments, the secondary coil 4b may be made of a copper wire with a transparent coating. In this case, some of the fluorescence emitted from the magnetic resonance member 1 to the outside of the magnetic resonance member 1 and the light guide members 41, 42 is reflected off the surface of the copper wire through the transparent coating and returns to the inside of the light guide members 41, 42 or the magnetic resonance member 1, so that the amount of fluorescence light received by the light receiving device 13 increases.

[0123] Furthermore, in any of the above embodiments, the secondary coil 4b may be a multi-layer wound coil.

[0124] In the above embodiment, the secondary coil is a bobbinless coil, but it may be wound on a bobbin if necessary. In that case, the bobbin has a through hole and supports the aforementioned light guide members 41, 42 (and magnetic resonance member 1) inserted into the through hole. [Industrial applicability]

[0125] The present invention can be applied, for example, to a magnetic field measuring device. [Explanation of Symbols]

[0126] 1. Magnetic resonance member 2. High-frequency magnetic field generator 2a, 61a-1, 61a-2 Coil section 2c,2d opening 3 Magnets 4 Flux Transformers 4a Primary coil 4b Secondary coil 10 Magnetic sensor section 11 High frequency power supply 12 Irradiation device 13 Light receiving device 41 Light guide member (Example of the first light guide member) 42 Light guide members (Example of a second light guide member) 45,46 recess 61b-1,61b-2 Terminal section 62-1 Plate-shaped member (an example of the first plate-shaped member) 62-2 Plate-shaped member (an example of a second plate-shaped member) 95 Optical components 96 Filling material

Claims

1. A magnetic resonance component capable of quantum manipulation of electron spins using microwaves, A high-frequency magnetic field generator that applies the microwave to the magnetic resonance member, A magnet that applies a static magnetic field to the magnetic resonance member, An irradiation device that irradiates the magnetic resonance member with incident light of a specific wavelength, A flux transformer that senses the magnetic field to be measured with a primary coil and applies an applied magnetic field corresponding to the sensed magnetic field to be measured to the magnetic resonance member with a secondary coil, A columnar first light guide member that guides the incident light to the magnetic resonance member, The system comprises a columnar second light guide member that guides the fluorescence emitted by the magnetic resonance member away from the magnetic resonance member, The magnetic resonance member is positioned between the end face of the first light guide member and the end face of the second light guide member in the hollow portion of the secondary coil of the flux transformer and the hollow portion of the magnet. The secondary coil is a bobbinless coil. A magnetic field measuring device characterized by the following.

2. The aforementioned high-frequency magnetic field generator includes a substantially circular and plate-shaped coil section that emits microwaves, The coil section has two openings, The first light guide member is positioned to penetrate one of the two openings, The second light guide member is positioned to penetrate the other of the two openings. A magnetic field measuring device according to claim 1, characterized by the following:

3. The aforementioned high-frequency magnetic field generator comprises two substantially circular coil sections that emit microwaves, At least a portion of the first light guide member and at least a portion of the second light guide member are arranged in the space between the two coil portions. A magnetic field measuring device according to claim 1, characterized by the following:

4. The substrate further comprises a wiring pattern that conducts the aforementioned high-frequency microwave current, A first plate-shaped member and, A second plate-shaped member is arranged substantially parallel to the first plate-shaped member, The first coil portion of the two coil portions is arranged on the surface of the first plate-shaped member. The second coil portion of the two coil portions is positioned on the surface of the second plate-shaped member facing the surface of the first plate-shaped member. The high-frequency magnetic field generator further comprises a first terminal portion extending from the first coil portion along the side surface of the first plate-shaped member, and a second terminal portion extending from the second coil portion along the side surface of the second plate-shaped member. The first plate-shaped member and the second plate-shaped member are each arranged upright on the substrate, The first terminal portion and the second terminal portion are electrically connected to the wiring pattern of the substrate. A magnetic field measuring device according to claim 3, characterized by the following:

5. The magnetic field measuring device according to claim 4, further comprising a filling member formed by filling the space between the first plate-shaped member and the second plate-shaped member with a cured resin.

6. The magnetic field measuring device according to claim 5, characterized in that the filling member is provided with an observation hole for optically observing the magnetic resonance member from the side opposite to the substrate.

7. The magnetic field measuring device according to any one of claims 1 to 6, further comprising an optical member disposed adjacent to the end face of the first light guide member, which transmits excitation light as incident light and reflects fluorescence.

8. The magnetic field measuring device according to any one of claims 1 to 6, characterized in that the secondary coil is wound around at least one of the first light guide member, the second light guide member, and the magnetic resonance member.

9. The magnetic field measuring device according to any one of claims 1 to 6, characterized in that the secondary coil comprises a copper wire and a transparent coating.

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