High-frequency magnetic field generating device

Abstract

The high-frequency magnetic field generating device of the present invention can generate a substantially uniform three-dimensional high-frequency magnetic field in a wide range and can improve the detection sensitivity of optical detection magnetic resonance and the like; two coils (L1, L2) are arranged parallel to each other at a predetermined interval with an electron spin resonance material sandwiched therebetween; a high-frequency power supply (1) generates a microwave current that is conducted to the two coils (L1, L2); two line bodies (S1, S2) are respectively connected to the two coils (L1, L2), and the current distribution is set in such a way that the two coils (L1, L2) are located outside the nodes of the standing wave.

Description

[0001] (This application is a divisional application of the application with applicant Sumida Group Co., Ltd., Chinese Application No. 201810921098.2, filing date August 14, 2018, and title "High-frequency magnetic field generating device".) Technical Field

[0002] The present invention relates to a high-frequency magnetic field generating device. Background Art

[0003] In optically detected magnetic resonance (ODMR), by simultaneously irradiating a medium having sub-levels and optical transition levels with a high-frequency magnetic field (microwave) and light, it is possible to highly sensitively detect changes in occupancy numbers caused by magnetic resonance between sub-levels based on the light signal.

[0004] Generally, electrons in the ground state emit red light when returning to the ground state after being excited by green light. On the other hand, for example, electrons in nitrogen and lattice defects (NVC: Nitrogen Vacancy Center) in a diamond structure, by irradiating a high-frequency magnetic field of about 2.87 GHz, transition from the lowest level (m s = 0) among the three sub-levels in the ground state to a level in a higher energy orbit in the ground state (m s = ±1). When the electrons in this state are excited by green light, since they return to the lowest level (m s = 0) among the three sub-levels in the ground state in a non-radiative manner, the amount of light emission decreases, and thus it is possible to determine whether magnetic resonance is caused by the high-frequency magnetic field based on the detection of this light. In ODMR, such a light-detecting magnetic resonance material called NVC is used.

[0005] In a measurement system, an open-loop resonator, or a coil or wire antenna is provided below a diamond sample, and a high-frequency magnetic field in the microwave region of about 2.87 GHz is irradiated from the resonator to the sample. The high-frequency magnetic field and the excitation light are scanned, and the detection device detects the point where the red light from the electrons decreases, thereby obtaining information about cells located near the above diamond structure (for example, refer to Non-Patent Document 1).

[0006] In addition, there is a magnetic measurement device that performs magnetic measurement by ODMR using electron spin resonance (for example, refer to Patent Document 1). In this magnetic measurement device, a microwave magnetic field is also generated by a single coil.

[0007]

Prior Art Documents

[0008]

Patent Documents

[0009] Patent Document 1: Japanese Patent Laid-Open No. 2012-110489

[0010]

Non-Patent Document

[0011] Non-Patent Document 1: Kento Sasaki, et.al., “Broadband, large-area microwave antenna for optically-detected magnetic resonance of nitrogen-vacancy centers in diamode” REVIEW OF SCIENTIFIC INSTRUMENTS 87, 053904(2016) Summary of the Invention

[0012] However, the above-mentioned coil and antenna can only generate a uniform three-dimensional high-frequency magnetic field within a very narrow range, and it is difficult to improve the detection sensitivity of ODMR. For example, in the case of Non-Patent Document 1, as Figure 20 shown, a loop antenna resonator using a circular copper plate with a radius of R (about 7 mm) has a slit formed at its center position, and further has a through hole with a radius of r (about 0.5 mm) formed at the front end of the slit. As Figure 21 shown, when a current of about 2.87 GHz is supplied from a high-frequency power supply, a uniform magnetic field can be generated in a region with a radius of about 1 mm from its center. However, in other regions outside this region, that is, in a region accounting for 98% of the area of this copper plate, the magnetic field intensity gradually decreases from the center of the coil and becomes a region that cannot be used for ODMR detection. In addition, the same problem also exists in other measurements using electron spin resonance such as electrically detected magnetic resonance (EDMR).

[0013] The present invention has been completed in view of the above problems, and its object is to obtain a high-frequency magnetic field generating device that can generate a substantially uniform three-dimensional high-frequency magnetic field within a wide range and can improve the detection sensitivity in measurements using electron spin resonance.

[0014] The high-frequency magnetic field generating device according to the present invention includes: two coils that are arranged parallel to each other at a predetermined interval with an electron spin resonance material sandwiched therebetween, or arranged parallel to each other at a predetermined interval on one side of the electron spin resonance material; a high-frequency power supply that generates a microwave current flowing through the two coils; and a transmission line portion that is connected to the two coils and sets the current distribution in such a way that the two coils are located outside the nodes of the standing wave.

[0015] In addition, the high-frequency magnetic field generating device according to the present invention includes a high-frequency power source, at least two pairs of coils, and at least two transmission lines including a transmission line between one coil of each of the two pairs of coils and a transmission line between the other coils of each of the two pairs of coils. The high-frequency power source generates a microwave current that conducts to the two coils forming a pair in each of the at least two pairs of coils. Further, each pair of coils in the at least two pairs of coils is arranged parallel to each other with a predetermined interval therebetween with an electron spin resonance material sandwiched therebetween, or is arranged parallel to each other with a predetermined interval therebetween on one side of the electron spin resonance material; in addition, the at least two transmission lines set a current distribution such that each coil in the at least two pairs of coils is located outside a node of a standing wave.

[0016] In addition, the high-frequency magnetic field generating device according to the present invention includes: a substrate, a through-hole in the substrate, a plate-shaped coil disposed in the through-hole, a high-frequency power source that generates a microwave current that conducts to the plate-shaped coil, and a transmission line portion that is connected to the plate-shaped coil and sets a current distribution such that the plate-shaped coil is located outside a node of a standing wave. The length direction of the cross-section of the plate-shaped coil is in the vertical direction of the substrate; one of the edge portions on the upper end side and one of the edge portions on the lower end side among the four edge portions of the plate-shaped coil function as two coils that are arranged parallel to each other with a predetermined interval therebetween with an electron spin resonance material sandwiched therebetween, or are arranged parallel to each other with a predetermined interval therebetween on one side of the electron spin resonance material.

[0017] (Advantages of the Invention)

[0018] According to the present invention, a high-frequency magnetic field generating device can be obtained that can generate a substantially uniform three-dimensional high-frequency magnetic field in a wide range and can improve the detection sensitivity of measurements using electron spin resonance. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a perspective view for explaining the arrangement of coils in the high-frequency magnetic field generating device according to an embodiment of the present invention.

[0020] Figure 2 It is a circuit diagram showing the configuration of the high-frequency magnetic field generating device according to the first embodiment of the present invention.

[0021] Figure 3 It is a circuit diagram showing the configuration of the high-frequency magnetic field generating device according to the second embodiment of the present invention.

[0022] Figure 4 It is a circuit diagram showing the configuration of the high-frequency magnetic field generating device according to the third embodiment of the present invention.

[0023] Figure 5It is a circuit diagram showing the configuration of the high-frequency magnetic field generating device according to the fourth embodiment of the present invention.

[0024] Figure 6 It is a perspective view illustrating an example of the arrangement of coils in the high-frequency magnetic field generating device according to the fourth embodiment of the present invention.

[0025] Figure 7 It is a perspective view illustrating the coils and the circuit body in the high-frequency magnetic field generating device according to the fifth embodiment of the present invention.

[0026] Figure 8 It is a perspective view illustrating the coils and the circuit body in the high-frequency magnetic field generating device according to the sixth embodiment of the present invention.

[0027] Figure 9 It is a perspective view showing another example of the circuit body in the high-frequency magnetic field generating device according to the sixth embodiment of the present invention.

[0028] Figure 10 It is a perspective view illustrating the coils and the circuit body in the high-frequency magnetic field generating device according to the seventh embodiment of the present invention.

[0029] Figure 11 It is a circuit diagram showing the configuration of the high-frequency magnetic field generating device according to the eighth embodiment of the present invention.

[0030] Figure 12 It is a circuit diagram showing the configuration of the high-frequency magnetic field generating device according to Modification 1 of the eighth embodiment of the present invention.

[0031] Figure 13 It is a circuit diagram showing the configuration of the high-frequency magnetic field generating device according to Modification 2 of the eighth embodiment of the present invention.

[0032] Figure 14 It is a circuit diagram showing the configuration of the high-frequency magnetic field generating device according to the ninth embodiment of the present invention.

[0033] Figure 15 It is a circuit diagram showing the configuration of the high-frequency magnetic field generating device according to the tenth embodiment of the present invention.

[0034] Figure 16 It is a diagram showing the configuration of the high-frequency magnetic field generating device according to the eleventh embodiment of the present invention.

[0035] Figure 17 It is a diagram showing the configuration of the high-frequency magnetic field generating device according to the twelfth embodiment of the present invention.

[0036] Figure 18 It is a diagram showing the configuration of the high-frequency magnetic field generating device according to the thirteenth embodiment of the present invention.

[0037] Figure 19 This is a diagram showing the simulation result of the magnetic field emitted by the high-frequency magnetic field generation device according to the sixth embodiment of the present invention.

[0038] Figure 20 This is a circuit diagram showing the configuration of an existing coil-type high-frequency generation device.

[0039] Figure 21 This is a diagram showing the magnetic field emitted by an existing coil-type high-frequency generation device. Detailed Embodiments

[0040] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0041] First Embodiment.

[0042] Figure 1 This is a perspective view for explaining the arrangement of coils in the high-frequency magnetic field generation device according to the embodiment of the present invention.

[0043] The high-frequency magnetic field generation device according to the embodiment of the present invention includes at least two coils L1 and L2. As Figure 1 shown, the two coils L1 and L2 are arranged parallel to each other with a predetermined interval (for example, about the diameter of each coil L1 and L2). In addition, the specimen 101 is arranged on a plate 102 such as diamond having NVC as an optically detected magnetic resonance material (hereinafter referred to as ODMR material), and further, the plate 102 is fixed to a specimen plate 103. Moreover, the two coils L1 and L2 are arranged with the plate 102 having NVC as the ODMR material interposed therebetween. In addition, the ODMR material is a kind of electron spin resonance material.

[0044] The shapes of the two coils L1 and L2 are the same as each other and are arranged with the same central axis. In addition, the number of turns of each of the coils L1 and L2 is approximately one turn (less than one turn) here. A microwave current is applied to the two coils L1 and L2, and the two coils L1 and L2 generate an alternating magnetic field as microwaves in the same phase (that is, the directions at each time point are the same). This alternating magnetic field is applied to the ODMR material, and a static magnetic field (not shown) different from the alternating magnetic field generated by the coils L1 and L2 is applied. And, measurement light such as laser with a predetermined wavelength is irradiated to the ODMR material through an optical system (not shown), and radiation light of a specific wavelength, for example, is observed, thereby performing measurement based on optically detected magnetic resonance (magnetic measurement, orientation of NVC, etc., temperature of NVC, etc.).

[0045] Figure 2 This is a circuit diagram showing the configuration of the high-frequency magnetic field generation device according to the first embodiment of the present invention.

[0046] As Figure 2As shown, the high-frequency magnetic field generating device according to the first embodiment further includes a high-frequency power supply 1 and two line bodies S1 and S2.

[0047] The high-frequency power supply 1 generates a microwave current that conducts to two coils L1 and L2. Specifically, the high-frequency power supply 1 generates a microwave current in a frequency band required for optically detected magnetic resonance (here, around 2.87 GHz).

[0048] The two line bodies S1 and S2 are transmission line portions respectively connected to the two coils L1 and L2, and the current distribution is set in such a way that the two coils L1 and L2 are located at positions outside the nodes of the standing wave.

[0049] In addition, each of the line bodies S1 and S2 can be formed as a line of a single conductor, or can be formed as a distributed parameter circuit using resistance elements, capacitor elements, etc.

[0050] Specifically, in the first embodiment, as Figure 2 shown, one end of each of the two line bodies S1 and S2 is open, and the other ends of the two line bodies S1 and S2 are respectively connected to one ends of the two coils L1 and L2. In addition, the other ends of the two coils L1 and L2 are electrically connected to each other, and the connection point is connected to the high-frequency power supply 1. Therefore, the microwave current flows from the high-frequency power supply 1 into the other ends of the two coils L1 and L2 respectively. In addition, the shapes of the two coils L1 and L2 are the same as each other, and the shapes of the line bodies S1 and S2 are also the same as each other. By configuring in this way, from the perspective of the high-frequency power supply 1, the coil L1 and the line body S1 and the coil L2 and the line body S2 have the same high-frequency characteristics (i.e., the same electrical length) as each other.

[0051] For example, when the electrical lengths of the coil L1 and the line body S1, and the coil L2 and the line body S2 are λ / 4 (λ: the wavelength of the microwave), the current distribution becomes as Figure 2 shown, and the coils L1 and L2 are located near the antinodes of the standing wave rather than at the nodes of the standing wave, and sufficient microwave current flows through the coils L1 and L2, thereby inducing a microwave magnetic field.

[0052] For example, when the high-frequency power supply 1 generates microwaves of 2.87 GHz, the wavelength is about 10 cm, so the electrical lengths of the coil L1 and the line body S1, and the coil L2 and the line body S2 are about 2.5 cm. In addition, in order to facilitate tuning, it is preferable to set the lengths of the coils L1 and L2 to be less than 1 / 2 of the lengths of the line bodies S1 and S2.

[0053] Next, the operation of the high-frequency magnetic field generating device according to the first embodiment will be described.

[0054] When the high-frequency power supply 1 generates an alternating current of microwaves, the microwave current flows to the coil L1 and the line body S1, and the coil L2 and the line body S2. Here, since the terminals of the coil L1 and the line body S1, and the terminals of the coil L2 and the line body S2 have achieved impedance matching, no other impedance matching measures are taken in this embodiment, and a standing wave as shown in Figure 2 is formed in the coil L1 and the line body S1, and the coil L2 and the line body S2.

[0055] As a result, alternating currents of the same phase and the same magnitude are conducted in the coils L1 and L2. A microwave magnetic field is formed by the current conducted to the coils L1 and L2. Since the coils L1 and L2 are coaxially and substantially parallelly arranged, in the space between the coil L1 and the coil L2, the direction of the magnetic field is substantially parallel to the central axis of the coils L1 and L2, and the magnetic fields are substantially the same.

[0056] In summary, according to the above first embodiment, the two coils L1 and L2 are arranged parallel to each other at a predetermined interval with the ODMR material sandwiched therebetween. The high-frequency power supply 1 generates a microwave current conducted to the two coils L1 and L2. The two line bodies S1 and S2 are respectively connected to the two coils L1 and L2, and the current distribution is set in such a way that the two coils L1 and L2 are located outside the nodes of the standing wave.

[0057] As a result, a substantially uniform three-dimensional high-frequency magnetic field is generated in a wide range of the space between the coil L1 and the coil L2. Thereby, the detection sensitivity of ODMR can be improved.

[0058] In addition, in this embodiment, one end of each of the line bodies S1 and S2 is open, but a circuit having a sufficiently high impedance at the same power supply (oscillation) frequency, for example, can be connected between the open end and the ground.

[0059] In addition, as shown in Figure 1 , the two coils L1 and L2 are arranged parallel to each other at a predetermined interval with the ODMR material sandwiched therebetween, but the ODMR material can also be arranged on one side of the two coils L1 and L2. In this case, although the resonance band becomes slightly narrower, there is an advantage that the degree of freedom in setting the ODMR material becomes higher.

[0060] In addition, in Figure 1 , the plate 102 and the test sample plate 103 are arranged perpendicular to the direction of the magnetic field (the central axis direction of the coils L1 and L2), but the plate 102 and the test sample plate 103 can also be arranged inclined with respect to the direction of the magnetic field (the central axis direction of the coils L1 and L2). In this case, the same magnetic field is also applied to the plate 102.

[0061] Second Embodiment.

[0062] Figure 3 This is a circuit diagram showing the configuration of the high-frequency magnetic field generating device according to the second embodiment of the present invention. The high-frequency magnetic field generating device according to the second embodiment has the same configuration as the high-frequency magnetic field generating device according to the first embodiment, and an impedance matching unit 11 is further provided between the high-frequency power supply 1 and the two coils L1 and L2.

[0063] When impedance matching is not performed between the high-frequency power supply 1 and the coils L1 and L2, the microwaves from the high-frequency power supply 1 will be reflected by the coils L1 and L2, resulting in insufficient microwave current flowing through the coils L1 and L2. Therefore, when impedance matching is not performed between the high-frequency power supply 1 and the coils L1 and L2, the impedance matching unit 11 is provided. Thereby, impedance matching is performed to transmit the microwaves from the high-frequency power supply 1 to the coils L1 and L2. As the impedance matching unit 11, for example, a resistance element (R), a capacitance element (C), an inductance element (L), or a combination of these elements can be used.

[0064] In addition, in Figure 3 the impedance matching unit 11 is arranged between the connection point of the coils L1 and L2 and the high-frequency power supply 1, but two impedance matching units 11 can also be respectively arranged between the coil L1 and the high-frequency power supply 1, and between the coil L2 and the high-frequency power supply 1.

[0065] In addition, in the high-frequency magnetic field generating device according to other embodiments described later, of course, the same impedance matching unit can also be provided. At that time, when the high-frequency power supply 1 is connected to two line bodies, the same impedance matching unit can also be provided between the high-frequency power supply 1 and the two line bodies.

[0066] In summary, according to the above second embodiment, even when impedance matching cannot be achieved only by the coils L1 and L2 or the line bodies S1 and S2, impedance matching can be realized through the above impedance matching unit 11.

[0067] Third Embodiment.

[0068] Figure 4 This is a circuit diagram showing the configuration of the high-frequency magnetic field generating device according to the third embodiment of the present invention. The high-frequency magnetic field generating device according to the third embodiment includes at least two pairs of coils (L1-i, L2-i) (i = 1,..., n; n > 1) and at least two line bodies S1-j, S2-j, where the at least two line bodies S1-j, S2-j include a line body S1-j located between the one coils L1-i of the at least two pairs of coils, and a line body S2-j located between the other coils L2-i of the at least two pairs of coils.

[0069] In the third embodiment, the high-frequency power supply 1 generates a microwave current that conducts to two coils L1-i and L2-i that are paired in each of the at least two pairs of coils (L1-i, L2-i) (i = 1,..., n).

[0070] Each of the at least two pairs of coils (L1-i, L2-i) is arranged parallel to each other at a predetermined interval with the ODMR material sandwiched therebetween. For example, the coils L1-1 to L1-n are arranged so that the induced microwave magnetic fields are in phase, and the coils L2-1 to L2-n are arranged so that the induced microwave magnetic fields are in phase. That is, the directions of the microwave magnetic fields induced by the coils L1-1 to L1-n and L2-1 to L2-n are the same.

[0071] In addition, the at least two line bodies S1-j and S2-j are transmission line portions that set the current distribution in such a way that each coil in the at least two pairs of coils L1-i and L2-i is located outside the nodes of the standing wave. For example, the electrical lengths of all the line bodies S1-j and S2-j are all set to the same length, and the line body S1-j and the coil L1-j are alternately arranged, and the line body S2-j and the coil L2-j are alternately arranged. Specifically, the line body S1-j is arranged between the coil L1-j and the coil L1-(j + 1), the line body S2-j is arranged between the coil L2-j and the coil L2-(j + 1), and the terminals of the terminal line bodies S1-n and S2-n are open.

[0072] For example, the coils L1-i and L2-i have the same shape and are arranged to have the same central axis. Here, when the number of turns of each of the coils L1-i and L2-i is approximately one turn (less than one turn), and the electrical lengths of the coils L1-1 to L1-n and the line body S1-j therebetween, and the electrical lengths of the coils L2-1 to L2-n and the line body S2-j therebetween are (2n - 1)λ / 4, it becomes Figure 4 the current distribution as shown, and all the coils L1-i and L2-i are located outside the nodes of the standing wave, and sufficient microwave current flows through the coils L1-i and L2-i to induce a microwave magnetic field.

[0073] In summary, according to the above third embodiment, since the number of coils L1-i and L2-i is large, the intensity of the induced high-frequency magnetic field can be increased.

[0074] Fourth embodiment.

[0075] Figure 5 It is a circuit diagram showing the configuration of the high-frequency magnetic field generating device according to the fourth embodiment of the present invention. As Figure 5As shown in the figure, the high-frequency magnetic field generating device according to the fourth embodiment includes two pairs of coils (L11, L21), (L12, L22), and two line bodies S11, S21 as transmission line parts.

[0076] Figure 6 FIG. is a perspective view for explaining an example of the arrangement of the coils L11, L21, L12, and L22 in the high-frequency magnetic field generating device according to the fourth embodiment of the present invention. As Figure 6 shown, the number of turns of each of the coils L11, L21, L12, and L22 is approximately half a turn. The coils L11 and L22 form a pair and induce a microwave magnetic field in phase. The coils L12 and L21 form a pair and induce a microwave magnetic field in phase.

[0077] In addition, the number of turns of each of the coils L11, L21, L12, and L22 may be approximately one turn as in the first to third embodiments, and the in-phase coils L11 and L22 may be arranged close to each other (i.e., a total of approximately two turns), and the in-phase coils L12 and L21 may be arranged close to each other.

[0078] Further, in the fourth embodiment, one end of each of the two coils L12 and L22 is grounded, and the other end of each of the two coils L12 and L22 is respectively connected to one end of the two line bodies S11 and S21. In addition, the other end of each of the two line bodies S11 and S21 is connected to one end of the two coils L11 and L21, and the other ends of the two coils L11 and L21 are connected to each other, and the connection point is connected to the high-frequency power supply 1. Then, the microwave current flows from the high-frequency power supply 1 into the other ends of the two line bodies S11 and S21 via the coils L11 and L21 respectively. Therefore, one end (the short-circuited end) of the coils L12 and L22 becomes the antinode of the current distribution. As Figure 5 shown, each of the coils L11, L12, L21, and L22 is located at a position outside the node of the current distribution.

[0079] Fifth Embodiment.

[0080] Figure 7 FIG. is a perspective view for explaining the coils and line bodies in the high-frequency magnetic field generating device according to the fifth embodiment of the present invention.

[0081] The high-frequency magnetic field generating device according to the fifth embodiment has the circuit configuration shown in the first embodiment or the second embodiment ( Figure 2 or Figure 3 ), and includes a substrate 21. Moreover, two coils L1 and L2 are arranged on one surface of the substrate 21 in a substantially perpendicular manner. In addition, in this fifth embodiment, the two line bodies S1 and S2 are respectively notch-shaped ring-shaped line members and are arranged on the other surface of the substrate 21 in a substantially perpendicular manner.

[0082] Moreover, as Figure 2 or Figure 3 shown, the coils L1 and L2, the line bodies S1 and S2, and the high-frequency power supply 1 are electrically connected, and this electrical connection is made through wiring patterns on the substrate 21, vias on the substrate 21, and the like.

[0083] In addition, the operation of the high-frequency magnetic field generating device according to the fifth embodiment is the same as that of the first embodiment or the second embodiment, so the description thereof is omitted.

[0084] Sixth Embodiment.

[0085] Figure 8 is a perspective view for explaining the coils and the line bodies in the high-frequency magnetic field generating device according to the sixth embodiment of the present invention.

[0086] The high-frequency magnetic field generating device according to the sixth embodiment has the circuit configuration shown in the first embodiment or the second embodiment ( Figure 2 or Figure 3 ), and includes a substrate 21. Moreover, the two coils L1 and L2 are arranged on one surface of the substrate 21 in a substantially perpendicular manner. In addition, in this sixth embodiment, the two line bodies S1 and S2 are respectively wiring patterns and are formed on any one surface of the substrate 21.

[0087] Figure 9 is a perspective view showing another example of the line bodies in the high-frequency magnetic field generating device according to the sixth embodiment of the present invention. As Figure 9 shown, the same branches 31 and 32 can be provided on the line bodies S1 and S2, respectively. By configuring in this way, the current distribution can be adjusted in the coils L1 and L2 and the line bodies S1 and S2, and moreover, the input bandwidth can be adjusted.

[0088] In addition, the operation of the high-frequency magnetic field generating device according to the sixth embodiment is the same as that of the first embodiment or the second embodiment, so the description thereof is omitted.

[0089] Seventh Embodiment.

[0090] Figure 10 is a perspective view for explaining the coils and the line bodies in the high-frequency magnetic field generating device according to the seventh embodiment of the present invention.

[0091] The high-frequency magnetic field generating device according to the seventh embodiment includes the circuit configuration shown in the fourth embodiment ( Figure 5 ), and includes a substrate 21. As Figure 10As shown, in the seventh embodiment, on the substrate 21, coils L11, L12, L21, and L22 are provided perpendicular to the substrate 21. One end of coil L11 and one end of coil L12 are connected to a cut-ring-shaped circuit body S11, and one end of coil L21 and one end of coil L22 are connected to a cut-ring-shaped circuit body S21.

[0092] As Figure 10 shown, the circuit bodies S11 and S21 are arranged perpendicular to the opening directions of the coils L11 and L22 and the opening directions of the coils L12 and L21 (i.e., the directions of the magnetic fields formed by the coils L11, L22, L12, and L21), so that the coils L11, L22, L12, and L21 are not easily magnetically coupled to the circuit bodies S11 and S21.

[0093] In addition, the operation of the high-frequency magnetic field generating device according to the seventh embodiment is the same as that of the fourth embodiment, so its description is omitted.

[0094] Eighth embodiment.

[0095] Figure 11 is a circuit diagram showing the configuration of the high-frequency magnetic field generating device according to the eighth embodiment of the present invention.

[0096] In the high-frequency magnetic field generating device according to the eighth embodiment, as Figure 11 shown, two coils L1 and L2 are connected in parallel, and a circuit body S1s as a transmission line part is connected to the connection point of the two coils L1 and L2. In the eighth embodiment, the current distribution is set by a circuit body S1s so that the two coils L1 and L2 are located outside the nodes of the standing wave.

[0097] Specifically, in the eighth embodiment, as Figure 11 shown, one end of the circuit body S1s is open, and the other end of the circuit body S1s is connected to one connection point of the two coils L1 and L2. In addition, the other connection point of the two coils L1 and L2 is connected to the high-frequency power supply 1. Therefore, the microwave current flows into the other ends of the two coils L1 and L2 from the high-frequency power supply 1. In addition, the shapes of the two coils L1 and L2 are the same. With such a configuration, from the perspective of the high-frequency power supply 1, the coil L1 and the circuit body S1s have the same high-frequency characteristics (i.e., the same electrical length) as the coil L2 and the circuit body S1s.

[0098] For example, when the electrical lengths of the coils L1, L2, and the circuit body S1s are λ / 4 (λ: wavelength of microwave), the current distribution is as Figure 11 shown. The coils L1 and L2 are located near the antinodes of the standing wave rather than at the nodes of the standing wave, and sufficient microwave current flows through the coils L1 and L2, thereby inducing a microwave magnetic field.

[0099] In addition, the operation of the high-frequency magnetic field generating device according to the eighth embodiment is the same as that of the first embodiment, so the description thereof is omitted.

[0100] In addition, Figure 11 As for the configuration of the high-frequency magnetic field generating device according to the eighth embodiment shown, it is also possible to adopt Figure 12 or Figure 13 the modified example shown.

[0101] Figure 12 FIG. is a circuit diagram showing the configuration of a high-frequency magnetic field generating device according to Modified Example 1 of the eighth embodiment of the present invention. In Figure 12 the Modified Example 1 shown, one end of the line body S1s that is not connected to the coils L1 and L2 is connected to one end of the variable capacitance element 41, and the other end of the variable capacitance element 41 is grounded. Thus, even if there is a deviation from the central axis, it is possible to adjust the center of the resonance frequencies of the coils L1 and L2 to be infinitely close to the desired frequency by changing the capacitance of the variable capacitance element 41. In addition, the variable capacitance element 41 only needs to have a very small capacitance value. For example, it may be a movable device that slightly moves a part of the position of the line body S1s. Alternatively, the variable capacitance element 41 may be, for example, a variable capacitor having a small capacitance.

[0102] Figure 13 FIG. is a circuit diagram showing the configuration of a high-frequency magnetic field generating device according to Modified Example 2 of the eighth embodiment of the present invention. In Figure 13 the Modified Example 2 shown, the other ends (i.e., the power supply side) of the coils L1 and L2 that are not connected to the line body S1s are connected to one end of the variable capacitance element 51, and the other end of the variable capacitance element 51 is grounded. Thus, similarly to the above Modified Example 1, even if, for example, the shapes of the coils L1 and L2 change or there is a deviation from the central axis, it is possible to adjust the center of the resonance frequencies of the coils L1 and L2 to be infinitely close to the desired frequency by changing the capacitance of the variable capacitance element 51. In addition, the variable capacitance element 51 only needs to have a very small capacitance value. For example, it may be a variable capacitor having a small capacitance, or a device that moves a part of the wire connecting the power supply and the coils L1 and L2.

[0103] Ninth Embodiment.

[0104] Figure 14 FIG. is a circuit diagram showing the configuration of a high-frequency magnetic field generating device according to the ninth embodiment of the present invention.

[0105] In the high-frequency magnetic field generating device according to the ninth embodiment, as Figure 14As shown, two coils L1 and L2 are connected in parallel, and a line body S1s serving as a transmission line section is connected to the connection point of the two coils L1 and L2. In the ninth embodiment, the current distribution is set by one line body S1s such that the two coils L1 and L2 are located at positions outside the nodes of the standing wave.

[0106] Specifically, in the ninth embodiment, as Figure 14 shown, one end of the line body S1s is connected to the high-frequency power supply 1 via an impedance matching unit 11, and the other end of the line body S1s is connected to one connection point of the two coils L1 and L2. In addition, the other connection point of the two coils L1 and L2 is connected to one end portion of another impedance matching unit 11. Further, the other end portion of the other impedance matching unit 11 is open. Therefore, the microwave current flows from the high-frequency power supply 1 into one ends of the two coils L1 and L2 through one impedance matching unit 11 and the line body S1s. In addition, the shapes of the two coils L1 and L2 are the same as each other. With such a configuration, from the perspective of the high-frequency power supply 1, the coil L1 and the line body S1s have the same high-frequency characteristics (i.e., the same electrical length) as the coil L2 and the line body S1s.

[0107] For example, when the electrical lengths of the coils L1, L2, and the line body S1s are λ / 4 (λ: wavelength of the microwave), the current distribution becomes as Figure 14 shown, and the coils L1 and L2 are located near the antinodes of the standing wave rather than at the nodes of the standing wave, and sufficient microwave current flows through the coils L1 and L2, thereby inducing a microwave magnetic field.

[0108] Tenth embodiment.

[0109] Figure 15 It is a circuit diagram showing the configuration of a high-frequency magnetic field generating device according to the tenth embodiment of the present invention.

[0110] In the high-frequency magnetic field generating device according to the tenth embodiment, as Figure 15 shown, two coils L1 and L2 are connected in parallel, and line bodies S1s serving as transmission line sections are respectively connected to the connection points of the two coils L1 and L2. In the tenth embodiment, the current distribution is set by two line bodies S1s such that the two coils L1 and L2 are located at positions outside the nodes of the standing wave.

[0111] Specifically, in the tenth embodiment, as Figure 15As shown, one end of a line body S1s is connected to a high-frequency power supply 1 via an impedance matching unit 11, and the other end of the line body S1s is connected to a connection point of two coils L1 and L2. In addition, the other connection point of the two coils L1 and L2 is connected to one end of another line body S1s. Further, the other end of the other line body is connected to one end portion of another impedance matching unit 11. Furthermore, the other end portion of the second impedance matching unit 11 is open. Therefore, the microwave current flows from the high-frequency power supply 1 into one end of each of the two coils L1 and L2 through the first impedance matching unit 11 and a line body S1s. In addition, the shapes of the two coils L1 and L2 are the same as each other, and the shapes of the two line bodies S1s and S1s are also the same as each other. By configuring in this way, from the perspective of the high-frequency power supply 1, the coil L1 and the two line bodies S1s have the same high-frequency characteristics (i.e., the same electrical length) as the coil L2 and the two line bodies S1s.

[0112] For example, when the electrical lengths of the coils L1, L2, and the two line bodies S1s are λ / 2 (λ: the wavelength of the microwave), the current distribution is as shown in Figure 15 As shown, the coils L1 and L2 are located near the antinodes of the standing wave rather than at the nodes of the standing wave, and sufficient microwave current flows through the coils L1 and L2, thereby inducing a microwave magnetic field.

[0113] Eleventh Embodiment.

[0114] Figure 16 It is a diagram showing the configuration of a high-frequency magnetic field generating device according to the eleventh embodiment of the present invention.

[0115] In this eleventh embodiment, the coils L1 and L2 are formed on the front and back surfaces of a substrate 61 having a predetermined thickness in the form of metal patterns parallel to each other. In addition, a through hole 62 passing through the centers of the coils L1 and L2 is provided. Through this through hole 62, not only when the pair of coils L1 and L2 are arranged on one side of the specimen at a predetermined distance from each other, but also when the specimen is arranged at an arbitrary position between the coils L1 and L2, a high-frequency alternating magnetic field can be applied to the specimen.

[0116] Furthermore, as shown in Figure 16 As shown, through holes 63 and 64 parallel to the radial direction of the coils L1 and L2 can also be formed within the wall thickness of the substrate 61. In this case, laser light is emitted from the through hole 63, and this light irradiates a specimen (not shown) within the through hole 62, and the reflected light is reflected in the up and down directions via the through hole 62, so that it can be detected by a microscope. On the other hand, the light passing through the specimen in the laser light exits from the through hole 64. Therefore, the emitted light can also be observed. In addition, considering the problem of light refraction, the diameter of the through hole 64 can be made larger than the diameter of the through hole 63.

[0117] In addition, in the eleventh embodiment, since the substrate 61 is sandwiched between the coil L1 and the coil L2, the mechanical characteristics and electrical performance in terms of stably forming the shapes of the coils L1 and L2 and stably maintaining the distance therebetween are excellent.

[0118] Twelfth embodiment.

[0119] Figure 17 FIG. is a diagram showing the configuration of a high-frequency magnetic field generating device according to the twelfth embodiment of the present invention.

[0120] In the twelfth embodiment, instead of the coils L1 and L2 in the eleventh embodiment, a plate-shaped coil La is provided. A through-hole 82 is provided in a substrate 81 having a predetermined thickness. The plate-shaped coil La is disposed in the through-hole. In the twelfth embodiment, the plate-shaped coil La is fixed to the inner wall of the substrate 81 facing the through-hole 82 in such a manner that the length direction of the cross-section of the plate-shaped coil La is perpendicular to the substrate 81. The cross-section of the plate-shaped coil La is substantially rectangular. In addition, the through-hole 82 may be a through-hole, and the plate-shaped coil La may be a coil formed by bending a thin metal plate such as a copper plate, or may be a metal foil formed on the inner peripheral surface of the through-hole 82 serving as the through-hole by electroplating or the like.

[0121] In addition, in the twelfth embodiment, the through-hole 82 has an observation hole portion 82a having a circular cross-section. And, one of the upper edge portions LaEU and one of the lower edge portions LaEL of the four edge portions LaEU and LaEL of the plate-shaped coil La (especially the edge portions in the observation hole portion 82a) function as two coils that are arranged parallel to each other with a predetermined interval therebetween so as to sandwich the electron spin resonance material, or are arranged parallel to each other with a predetermined interval on one side of the electron spin resonance material. That is, due to the skin effect caused by high frequency (especially above MHz), the current concentrates on the edge portions LaEU and LaEL of the plate-shaped coil La, and thus, substantially the upper edge portion LaEU and the lower edge portion LaEL function as coils, respectively. In addition, it is preferable that the height (the length of the long side of the cross-section) of the plate-shaped coil La is substantially equal to the radius of the circular portion of the plate-shaped coil La so as to have the same layout as that of the Helmholtz coil. In addition, in order to suppress the variation of the parasitic capacitance between the plate-shaped coil La and the lens barrel of the microscope, it is preferable that the width (the length of the short side of the cross-section) of the plate-shaped coil La is much smaller than the height of the plate-shaped coil La.

[0122] In addition, through the through-hole 82, not only when the edge portion LaEU on the upper end side and the edge portion LaEL on the lower end side of the plate-shaped coil La are arranged on one side of the specimen at a predetermined distance from each other, but also when the specimen is arranged at an arbitrary position between the edge portion LaEU on the upper end side and the edge portion LaEL on the lower end side of the plate-shaped coil La, a high-frequency alternating magnetic field can be applied to the specimen.

[0123] Furthermore, as Figure 17 shown, through-holes 83 and 84 parallel to the radial direction of the circular portion of the plate-shaped coil La may be formed within the wall thickness of the substrate 81, and through-holes 85a and 85b of the plate-shaped coil La may be formed on the extension lines of the through-holes 83 and 84. In this case, laser light is emitted from the through-hole 83 and the through-hole 85a, and this light is irradiated onto the specimen (not shown) within the through-hole 82. The reflected light is reflected in the vertical direction via the through-hole 82, and thus can be detected by a microscope. On the other hand, the light that passes through the specimen in the laser light is emitted from the through-hole 85b and the through-hole 84. Therefore, the emitted light can also be observed. In addition, considering the problem of light refraction, the diameters of the through-holes 85b and 84 may be made larger than the diameters of the through-holes 83 and 85a.

[0124] In addition, the other configurations and operations of the high-frequency magnetic field generating device according to the twelfth embodiment are the same as any one or a combination of both of the ninth embodiment and the eleventh embodiment, and thus the description thereof is omitted.

[0125] In summary, according to the above twelfth embodiment, by using the above plate-shaped coil La, the DC resistance of the coil is lowered. In addition, when there are metal objects such as the housing of a microscope for observation or dielectric objects such as a specimen stage around the coil, the resonance frequency may change due to the presence of these objects. However, by using the above plate-shaped coil La, the change in the resonance frequency can be suppressed.

[0126] For example, when the thickness of the substrate is 1.6 mm and the radius of the circular portion of the plate-shaped coil La is 2 mm, the resonance frequency in the twelfth embodiment is 2.96 GHz when the specimen is arranged within the through-hole 82, and 2.965 GHz when the lens of the microscope is arranged at a distance of 1.5 mm. On the other hand, in the case of the comparative example, it is 2.84 GHz when the specimen is arranged within the through-hole, and 2.89 GHz when the lens of the microscope is arranged at a distance of 1.5 mm. Thus, the change in the resonance frequency is suppressed.

[0127] Thirteenth Embodiment.

[0128] Figure 18FIG. 0 is a diagram showing the configuration of the high-frequency magnetic field generating device according to the thirteenth embodiment of the present invention. In the thirteenth embodiment, the through-hole 82 has a substantially rectangular shape, and the plate-like coil La is disposed within the through-hole 82. In the thirteenth embodiment, the plate-like coil La is fixed so as to protrude from the inner wall of the substrate 81 facing the through-hole 82.

[0129] In addition, the other configurations and operations of the high-frequency magnetic field generating device according to the thirteenth embodiment are the same as those of the twelfth embodiment, and thus the description thereof is omitted.

[0130] It should be noted that, with respect to the above embodiments, various changes and modifications can be made without departing from the gist and scope thereof and without weakening the intended advantages. Since these changes and modifications are obvious to those skilled in the art, these changes and modifications should also be included within the scope of the claims of the present application.

[0131] For example, in the above embodiment, instead of opening or short-circuiting the ends of the two line bodies, the ends of the two line bodies can be closed with a specified resistance value.

[0132] In addition, in the above fourth embodiment, the coils L11 and L21 can be removed, the line bodies S11 and S21 can be connected to each other, and the connection point thereof can be connected to the high-frequency power supply 1.

[0133] In addition, in the above embodiment, the line body is used as the transmission line unit, but the line body can be replaced with a lumped parameter circuit as needed.

[0134] In addition, in the above embodiment, diamond having NVC is cited as the ODMR material. However, other ODMR materials having color centers (such as SiC color centers, or color centers of ZnO, GaN, Si, organic substances, etc.) can be used instead. In addition, the high-frequency power supply 1 generates a microwave current having a frequency corresponding to each color center.

[0135] In addition, in the above embodiment, the high-frequency magnetic field generating device can form a uniform magnetic field in a region substantially equal to the opening area of the coil. Therefore, particularly in the high-frequency region of 100 MHz or more, although it is applicable to ODMR, it can also be applicable to other measurements using electron spin resonance such as EDMR. Figure 19 FIG. 23 is a diagram showing the simulation results of the magnetic field emitted by the high-frequency magnetic field generating device according to the sixth embodiment of the present invention. In this simulation, the condition of supplying a current of about 3 GHz from the power supply to the coils L1 and L2 is implemented, and as a result, as Figure 19 shown, a uniform magnetic field is generated in substantially the entire region of the opening area from the centers of the coils L1 and L2 (for example, a region having an error of 10% from the central value of the magnetic field intensity).

[0136] In addition, in a region below 100 MHz, the high-frequency magnetic field generation device according to each embodiment of the present invention can also be used in the same manner as an existing coil-type oscillator.

[0137] (Industrial availability)

[0138] The present invention can be applied to, for example, a high-frequency magnetic field generation device for optical detection magnetic resonance.

Claims

1. A high-frequency magnetic field generating device, characterized in that, it comprises: a plate-shaped coil, and a high-frequency power supply that generates a microwave current conducted to the plate-shaped coil; one edge portion on the upper end side and one edge portion on the lower end side among the four edge portions of the plate-shaped coil function as two coils that are arranged parallel to each other with a predetermined interval therebetween while sandwiching an electron spin resonance material, or are arranged parallel to each other with a predetermined interval on one side of the electron spin resonance material; the plate-shaped coil has a circular portion and two through holes in the circular portion, light irradiated to the electron spin resonance material enters through one of the two through holes, and the irradiated light exits through the other of the two through holes.

2. The high-frequency magnetic field generating device according to claim 1, characterized in that, it further comprises a substrate; the length direction of the cross-section of the plate-shaped coil is the vertical direction of the substrate.

3. The high-frequency magnetic field generating device according to claim 1, characterized in that, it further comprises: a substrate; and a through hole in the substrate; the plate-shaped coil is disposed in the through hole.

4. The high-frequency magnetic field generating device according to claim 1, characterized in that, it further comprises a transmission line portion that is connected to the plate-shaped coil and sets a current distribution such that the plate-shaped coil is located at a position outside a node of a standing wave.

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