High frequency magnetic field generating device

Abstract

The high-frequency magnetic field generating device of the present invention can generate a roughly 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 in parallel with each other at a predetermined interval in a manner of sandwiching an electron spin resonance material; 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 a manner 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 applicant is SUMIDA GROUP CO., LTD., the Chinese application number is 201810921098.2, the filing date is August 14, 2018, and the title is “HIGH FREQUENCY MAGNETIC FIELD GENERATING DEVICE”.) Technical Field

[0002] The 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 sublevels and optical transition levels with a high-frequency magnetic field (microwaves) and light, changes in the occupancy number caused by magnetic resonance between sublevels can be detected with high sensitivity from optical signals.

[0004] Normally, ground state electrons emit red light when they return to the ground state after being excited by green light. On the other hand, electrons in nitrogen and lattice defects (NVC: Nitrogen Bacancy Center) in the diamond structure, for example, are excited by a high-frequency magnetic field of about 2.87 GHz and return to the lowest energy level (m s = 0) to the energy level of the ground state with a higher energy orbital (m s = ±1). When the electrons in this state are excited by green light, they recover to the lowest energy level (m s =0), the light emission amount is reduced, and it is possible to know whether magnetic resonance is induced by the high-frequency magnetic field based on the light detection. In ODMR, such a light detection magnetic resonance material called NVC is used.

[0005] In one measurement system, an open ring resonator, or a coil or wire antenna is set below the diamond sample, and a high-frequency magnetic field in the microwave region of about 2.87 GHz is irradiated to the sample from the resonator. The high-frequency magnetic field and the excitation light are scanned, and the reduction point of red light from the electrons is detected by a detection device, thereby obtaining information about cells located near the above-mentioned 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 (see, for example, Patent Document 1). In this magnetic measurement device, a microwave magnetic field is also generated by a single coil.

[0007] [Prior art literature]

[0008] [Patent Literature]

[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 Fig. 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 Fig.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 intensity of the magnetic field 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 comprises a high-frequency power supply, 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 coil of each of the two pairs of coils. The high-frequency power supply generates microwave currents that are conducted to the two coils of each pair of the at least two pairs of coils. Furthermore, each pair of coils of the at least two pairs of coils is arranged in parallel with each other at a predetermined interval in a manner of sandwiching an electron spin resonance material, or is arranged in parallel with each other at a predetermined interval on one side of the electron spin resonance material; in addition, the current distribution of the at least two transmission lines is set in a manner that each coil of the at least two pairs of coils is located at a position outside the node of the standing wave.

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

[0017] (Effects of the Invention)

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

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

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

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

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

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

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

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

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

[0027] Fig. 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] Fig.10 It is a perspective view for explaining a coil and a circuit body in a high-frequency magnetic field generating device according to a seventh embodiment of the present invention.

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

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

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

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

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

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

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

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

[0037] Fig.19 It is a diagram showing simulation results of the magnetic field generated by the high-frequency magnetic field generating device according to the sixth embodiment of the present invention.

[0038] Fig. 20 This is a circuit diagram showing the structure of a conventional coil type high frequency generator.

[0039] Fig.21 This is a diagram showing a magnetic field generated by a conventional coil-type high-frequency generator. DETAILED DESCRIPTION

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

[0041] First implementation method.

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

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

[0044] The two coils L1 and L2 are identical in shape to each other and are configured to have the same central axis. In addition, the number of turns of each coil L1 and L2 is approximately one turn (less than one turn). A microwave current is connected to the two coils L1 and L2, and the two coils L1 and L2 respectively generate an alternating magnetic field as a microwave in the same phase (i.e., the direction is the same at each time point). The alternating magnetic field is applied to the ODMR material, and a static magnetic field not shown in the figure is applied that is different from the alternating magnetic field generated by the coils L1 and L2. In addition, a measurement light such as a laser of a specified wavelength is irradiated to the ODMR material through an optical system not shown in the figure, and the radiated light of, for example, a specific wavelength is observed, thereby performing measurements based on optical detection magnetic resonance (magnetic measurement, orientation of NVC, etc., temperature of NVC, etc., etc.).

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

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

[0047] The high-frequency power source 1 generates a microwave current to be conducted to the two coils L1 and L2. Specifically, the high-frequency power source 1 generates a microwave current in a frequency band (here, about 2.87 GHz) required for optical detection of magnetic resonance.

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

[0049] In addition, each of the line bodies S1 and S2 may be configured as a line of a single conductor, or may be configured as a distributed parameter circuit using a resistor element, a capacitor element, or the like.

[0050] Specifically, in the first embodiment, if Figure 2 As shown, one end of each of the two line bodies S1 and S2 is open, and the other end of each of the two line bodies S1 and S2 is connected to one end of each of the two coils L1 and L2. In addition, the other ends of each of the two coils L1 and L2 are electrically connected to each other, and their connection points are connected to the high-frequency power supply 1. Therefore, microwave current flows from the high-frequency power supply 1 to the other ends of each of the two coils L1 and L2. 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. With such a structure, 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).

[0051] For example, when the electrical length of the coil L1 and the line body S1, and the electrical length of the coil L2 and the line body S2 are λ / 4 (λ: wavelength of microwaves), Figure 2 In the current distribution shown in FIG. 1 , coils L1 and L2 are located near the antinode of the standing wave rather than at the node of the standing wave. Sufficient microwave current flows in coils L1 and L2 to induce a microwave magnetic field.

[0052] For example, when the high frequency power source 1 generates microwaves of 2.87 GHz, the wavelength is about 10 cm, so the electrical length of the coil L1 and the line body S1, and the electrical length of the coil L2 and the line body S2 are about 2.5 cm. In addition, in order to facilitate tuning, it is preferred that the length of the coils L1 and L2 be set to be less than 1 / 2 of the length 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 source 1 generates microwave alternating current, 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 already achieved impedance matching, no other impedance matching measures are taken in this embodiment, and the coil L1 and the line body S1, and the coil L2 and the line body S2 are formed. Figure 2 Standing waves as shown.

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

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

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

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

[0059] In addition, if Figure 1 As shown, the two coils L1 and L2 are arranged parallel to each other at a predetermined interval so as to sandwich the ODMR material, but the ODMR material may be arranged on one side of the two coils L1 and L2. In this case, although the resonance frequency band is slightly narrowed, there is an advantage that the degree of freedom in setting the ODMR material is increased.

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

[0061] Second implementation method.

[0062] Figure 3 The high frequency magnetic field generating device according to the second embodiment of the present invention has the same structure as the high frequency magnetic field generating device according to the first embodiment, and further includes an impedance matching unit 11 between the high frequency power source 1 and the two coils L1 and L2.

[0063] In the case where impedance matching is not performed between the high-frequency power source 1 and the coils L1 and L2, the microwave from the high-frequency power source 1 is reflected by the coils L1 and L2, so that the microwave current flowing in the coils L1 and L2 is insufficient. Therefore, in the case where impedance matching is not performed between the high-frequency power source 1 and the coils L1 and L2, an impedance matching unit 11 is provided. Thus, impedance matching is performed, and the microwave from the high-frequency power source 1 is transmitted to the coils L1 and L2. As the impedance matching unit 11, for example, a resistor element (R), a capacitor element (C), an inductor element (L), or a combination of these elements can be used.

[0064] In addition, Figure 3 In the embodiment, the impedance matching section 11 is arranged between the connection point of the coil L1 and the coil L2 and the high frequency power source 1, but two impedance matching sections 11 may be arranged respectively between the coil L1 and the high frequency power source 1 and between the coil L2 and the high frequency power source 1.

[0065] In addition, in the high frequency magnetic field generating devices according to other embodiments described below, the same impedance matching section may be provided. In this case, when the high frequency power source 1 is connected to two line bodies, the same impedance matching section may be provided between the high frequency power source 1 and the two line bodies.

[0066] In summary, according to the 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 achieved by the impedance matching unit 11 .

[0067] The third implementation method.

[0068] Figure 4 1 is a circuit diagram showing the structure of a high-frequency magnetic field generating device according to a third embodiment of the present invention. The high-frequency magnetic field generating device according to the third embodiment comprises 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, wherein the at least two line bodies S1-j, S2-j include line bodies S1-j located between one coil L1-i of each of the at least two pairs of coils, and line bodies S2-j located between the other coils L2-i of each of the at least two pairs of coils.

[0069] In the third embodiment, the high frequency power source 1 generates microwave currents to be conducted to the two coils L1 - i and L2 - i forming a pair in each of the at least two pairs of coils ( L1 - i and 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 in a manner of sandwiching the ODMR material. 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 parts 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 node of the standing wave. For example, the electrical lengths of all line bodies S1-j and S2-j are set to the same length, and the line bodies S1-j and coils L1-j are arranged alternately, and the line bodies S2-j and coils L2-j are arranged alternately. Specifically, the line body S1-j is arranged between the coil L1-j and the coil L1-(j+1), and the line body S2-j is arranged between the coil L2-j and the coil L2-(j+1), and the terminals of the line bodies S1-n and S2-n at the end 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 coil L1-i and L2-i is approximately one turn (less than one turn), and the electrical length of the coils L1-1 to L1-n and the line body S1-j therebetween, and the electrical length of the coils L2-1 to L2-n and the line body S2-j therebetween is (2n-1)λ / 4, Figure 4 In the current distribution shown in FIG. 1 , all 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, thereby inducing a microwave magnetic field.

[0073] In summary, according to the 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 FIG. 4 is a circuit diagram showing the structure of a high-frequency magnetic field generating device according to a fourth embodiment of the present invention. Figure 5As shown, 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 portions.

[0076] Figure 6 1 is a perspective view for explaining an example of the arrangement of coils L11, L21, L12, and L22 in the high-frequency magnetic field generating device according to the fourth embodiment of the present invention. Figure 6 As shown, the number of turns of each coil L11, L21, L12, and L22 is approximately half a turn, the coil L11 and the coil L22 form a pair, and induce microwave magnetic fields in phase, and the coil L12 and the coil L21 form a pair, and induce microwave magnetic fields in phase.

[0077] In addition, the number of turns of each coil L11, L21, L12, and L22 can be roughly one turn, similar to the first to third embodiments, and the coils L11 and L22 of the same phase can be arranged close to each other (that is, a total of about two turns), and the coils L12 and L21 of the same phase can be arranged close to each other.

[0078] In addition, 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 connected to one end of each 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 each of the two coils L11 and L21. The other ends of each 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. Thus, the microwave current flows from the high-frequency power supply 1 through the coils L11 and L21 to the other ends of each of the two line bodies S11 and S21. Therefore, one end of the coils L12 and L22 (the short-circuited end) becomes an antinode of the current distribution, as shown in FIG. Figure 5 As shown, each coil L11, L12, L21, L22 is located outside the node of the current distribution.

[0079] Fifth embodiment.

[0080] Figure 7 It is a perspective view for explaining a coil and a circuit body in a high-frequency magnetic field generating device according to a fifth embodiment of the present invention.

[0081] A high-frequency magnetic field generating device according to a fifth embodiment includes 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 vertical manner. In addition, in the fifth embodiment, the two line bodies S1 and S2 are respectively line members in the form of cutout rings, and are arranged on the other surface of the substrate 21 in a substantially vertical manner.

[0082] Moreover, if Figure 2 or Figure 3 As shown, the coils L1 and L2 , the line bodies S1 and S2 , and the high-frequency power source 1 are electrically connected, and the electrical connection is performed through a wiring pattern on the substrate 21 , a through hole on the substrate 21 , and the like.

[0083] Note that 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, and thus the description thereof will be omitted.

[0084] Sixth embodiment.

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

[0086] The high-frequency magnetic field generating device according to the sixth embodiment has 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 vertical manner. In addition, in the sixth embodiment, the two line bodies S1 and S2 are wiring patterns and are formed on any one surface of the substrate 21.

[0087] Fig. 9 FIG. 2 is a perspective view showing another example of a circuit body in the high-frequency magnetic field generating device according to the sixth embodiment of the present invention. Fig. 9 As shown, the same branches 31 and 32 may be provided on the line bodies S1 and S2, respectively. With such a configuration, the current distribution in the coils L1 and L2 and the line bodies S1 and S2 can be adjusted, and the input bandwidth can also be adjusted.

[0088] Note that 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, and thus the description thereof will be omitted.

[0089] Seventh implementation method.

[0090] Fig.10 It is a perspective view for explaining a coil and a circuit body in a high-frequency magnetic field generating device according to a seventh embodiment of the present invention.

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

[0092] like Fig.10 As shown, the line bodies S11 and S21 are arranged perpendicularly 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 with the line 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, and thus the description thereof is omitted.

[0094] Eighth implementation method.

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

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

[0097] Specifically, in the eighth embodiment, if Fig.11 As shown, one end of the line body S1s is open, and the other end of the line body S1s is connected to a 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 from the high-frequency power supply 1 to the other end of each of the two coils L1 and L2. In addition, the shapes of the two coils L1 and L2 are the same as each other. With such a structure, from the perspective of the high-frequency power supply 1, the coil L1 and the line body S1s and the coil L2 and the line body S1s have the same high-frequency characteristics (i.e., the same electrical length).

[0098] For example, when the electrical length of the coils L1, L2 and the line body S1s is λ / 4 (λ: wavelength of microwaves), Fig.11 In the current distribution shown in FIG. 1 , coils L1 and L2 are located near the antinode of the standing wave rather than at the node of the standing wave. Sufficient microwave current flows in coils L1 and L2 to induce 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, and thus the description thereof is omitted.

[0100] also, Fig.11 The structure of the high frequency magnetic field generating device involved in the eighth embodiment shown in FIG. Fig.12 or Fig.13 The variation shown.

[0101] Fig.12 : is a circuit diagram showing the configuration of a high-frequency magnetic field generating device according to a first variation of the eighth embodiment of the present invention. Fig.12 In the variation 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 a deviation occurs from the central axis, the electrostatic capacitance of the variable capacitance element 41 can be changed so that the center of the resonant frequency of the coils L1 and L2 is infinitely close to the desired frequency. In addition, the variable capacitance element 41 only needs to have a very small electrostatic capacitance value, for example, it can also be a movable device that slightly moves the position of a part of the line body S1s. Alternatively, the variable capacitance element 41 can also be, for example, a variable capacitor with a tiny electrostatic capacitance.

[0102] Fig.13 FIG. 2 is a circuit diagram showing the configuration of a high-frequency magnetic field generating device according to a second variation of the eighth embodiment of the present invention. Fig.13 In the variation 2 shown, the other end of the coils L1 and L2 that is not connected to the line body S1s (i.e., the power supply side) is connected to one end of the variable capacitance element 51, and the other end of the variable capacitance element 51 is grounded. Thus, similar to the above-mentioned variation 1, even if, for example, the shape of the coils L1 and L2 changes, or deviates from the central axis, the electrostatic capacitance of the variable capacitance element 51 can be changed, so that the center of the resonant frequency of the coils L1 and L2 is infinitely close to the desired frequency. In addition, the variable capacitance element 51 only needs to have a very small electrostatic capacitance value, for example, it can also be a variable capacitor with a tiny electrostatic capacitance, or a device that moves a part of the conductive line between the power supply and the coils L1 and L2.

[0103] Ninth implementation method.

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

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

[0106] Specifically, in the ninth embodiment, if Fig.14 As shown, one end of the line body S1s is connected to the high-frequency power supply 1 via an impedance matching section 11, and the other end of the line body S1s is connected to a 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 of another impedance matching section 11. Furthermore, the other end of the other impedance matching section 11 is open. Therefore, the microwave current flows from the high-frequency power supply 1 through an impedance matching section 11 and the line body S1s into one end of each of the two coils L1 and L2. 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 and the coil L2 and the line body S1s have the same high-frequency characteristics (i.e., the same electrical length).

[0107] For example, when the electrical length of the coils L1, L2 and the line body S1s is λ / 4 (λ: wavelength of microwaves), Fig.14 In the current distribution shown in FIG. 1 , coils L1 and L2 are located near the antinode of the standing wave rather than at the node of the standing wave. Sufficient microwave current flows in coils L1 and L2 to induce a microwave magnetic field.

[0108] The tenth implementation method.

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

[0110] In the high-frequency magnetic field generating device according to the tenth embodiment, Fig.15 As shown, two coils L1 and L2 are connected in parallel, and a line body S1s as a transmission line portion is connected to the connection point of the two coils L1 and L2. In the tenth embodiment, the current distribution is set by the two line bodies S1s so that the two coils L1 and L2 are located outside the nodes of the standing wave.

[0111] Specifically, in the tenth embodiment, if Fig.15As shown, one end of a line body S1s is connected to the high-frequency power supply 1 via an impedance matching section 11, and the other end of the line body S1s is connected to a 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 of another line body S1s. In addition, the other end of the other line body is connected to one end of another impedance matching section 11. Furthermore, the other end of the second impedance matching section 11 is open. Therefore, the microwave current flows from the high-frequency power supply 1 through the first impedance matching section 11 and the line body S1s into one end of each of the two coils L1 and L2. 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. With such a configuration, from the perspective of the high-frequency power supply 1, the coil L1 and the two line bodies S1s and the coil L2 and the two line bodies S1s have the same high-frequency characteristics (i.e., the same electrical length).

[0112] For example, when the electrical lengths of the coils L1, L2 and the two line elements S1s are λ / 2 (λ: wavelength of microwaves), Fig.15 In the current distribution shown in FIG. 1 , coils L1 and L2 are located near the antinode of the standing wave rather than at the node of the standing wave. Sufficient microwave current flows in coils L1 and L2 to induce a microwave magnetic field.

[0113] The eleventh implementation method.

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

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

[0116] Furthermore, if Fig.16 As shown, through holes 63 and 64 parallel to the radial direction of coils L1 and L2 can also be formed in the wall thickness of substrate 61. In this case, laser light is emitted from through hole 63, and the light is irradiated on the sample (not shown) in the through hole 62, and its reflected light is reflected in the up and down directions through the through hole 62, so that it can be detected by a microscope. On the other hand, the light in the laser that passes through the sample is emitted from through hole 64. Therefore, its emitted light can also be observed. In addition, considering the refraction of light, the diameter of through hole 64 can also be made larger than the diameter of 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 shapes of the coils L1 and L2 are stably formed, the distance between the coils L1 and L2 is stably maintained, and the mechanical characteristics and electrical performance are excellent.

[0118] Twelfth implementation method.

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

[0120] In the twelfth embodiment, a plate-like coil La is provided instead of the coils L1 and L2 in the eleventh embodiment. A through hole 82 is provided on a substrate 81 having a predetermined thickness. The plate-like coil La is arranged in the through hole. In the twelfth embodiment, the plate-like 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-like coil La is the vertical direction of the substrate 81. The cross section of the plate-like coil La is roughly rectangular. In addition, the through hole 82 may also be a through hole, and the plate-like 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 by electroplating or the like on the inner peripheral surface of the through hole serving as the through hole 82.

[0121] In addition, in the twelfth embodiment, the through hole 82 has an observation hole portion 82a with a circular cross section. And, among the four edge portions LaEU and LaEL of the plate-like coil La (especially the edge portion in the observation hole portion 82a), one of the edge portions LaEU located on the upper end side and one of the edge portions LaEL located on the lower end side function as two coils arranged in parallel with each other at a predetermined interval in a manner of sandwiching the electron spin resonance material, or arranged in parallel with each other at a predetermined interval on one side of the electron spin resonance material. That is, under the action of the skin effect caused by high frequency (especially above the MHz level), the current concentrates on the edge portions LaEU and LaEL of the plate-like coil La, so that the edge portion LaEU on the upper end side and the edge portion LaEL on the lower end side essentially function as coils, respectively. In addition, it is preferred that the height of the plate-like coil La (the length of the long side of the cross section) is approximately equal to the radius of the circular portion of the plate-like coil La so as to be the same as the layout of the Helmholtz coil. Furthermore, in order to suppress the variation of the parasitic capacitance between the plate-like coil La and the lens barrel of the microscope, it is preferable to make the width (short side length of the cross section) of the plate-like coil La much smaller than the height of the plate-like coil La.

[0122] In addition, through the through hole 82, a high-frequency AC magnetic field can be applied to the sample 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 sample at a prescribed distance, but also when the sample is arranged at any 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.

[0123] Furthermore, if Fig.17 As shown, through holes 83 and 84 parallel to the radial direction of the circular part of the plate-like coil La can also be formed in the wall thickness of the substrate 81, and through holes 85a and 85b of the plate-like coil La can be formed on the extension lines of the through holes 83 and 84. In this case, laser light is emitted from the through holes 83 and 85a, and the light is irradiated on the sample (not shown) in the through hole 82, and the reflected light is reflected in the up and down directions through the through hole 82, so that it can be detected by a microscope. On the other hand, the light in the laser that passes through the sample is emitted from the through hole 85b and the through hole 84. Therefore, the emitted light can also be observed. In addition, considering the refraction of light, the diameter of the through holes 85b and 84 can also be made larger than the diameter of the through holes 83 and 85a.

[0124] In addition, other structures and operations of the high-frequency magnetic field generating device involved in the twelfth embodiment are the same as any one of the ninth embodiment and the eleventh embodiment or a combination of both, so their description is omitted.

[0125] In summary, according to the twelfth embodiment, the DC resistance of the coil is reduced by using the plate-shaped coil La. In addition, when there are metal objects such as the shell of a microscope for observation, or dielectric objects such as a sample stand, around the coil, the resonant frequency generated by the presence of such objects may change, however, by using the plate-shaped coil La, the change of the resonant 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 resonant frequency in the twelfth embodiment is 2.96 GHz when the sample is arranged in the through hole 82, and is 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, the resonant frequency is 2.84 GHz when the sample is arranged in the through hole, and is 2.89 GHz when the lens of the microscope is arranged at a distance of 1.5 mm. Thus, the change in the resonant frequency is suppressed.

[0127] Thirteenth implementation method.

[0128] Fig.181 is a diagram showing the structure of a high-frequency magnetic field generating device according to the thirteenth embodiment of the present invention. In the thirteenth embodiment, the through hole 82 is substantially rectangular, and the plate-like coil La is disposed in the through hole 82. In the thirteenth embodiment, the plate-like coil La is fixed in a manner protruding from the inner wall of the substrate 81 facing the through hole 82.

[0129] In addition, the other structures and operations of the high-frequency magnetic field generating device involved in 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 various changes and modifications may be made to the above-mentioned embodiments without departing from the spirit and scope thereof and without diminishing the intended advantages thereof. Since these changes and modifications are obvious to those skilled in the art, these changes and modifications should also be included in the scope of the claims of this application.

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

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

[0133] Furthermore, in the above-described embodiment, a line body is used as the transmission line portion, but the line body may be replaced with a lumped parameter circuit as necessary.

[0134] In the above embodiment, diamond with NVC is cited as the ODMR material, but other ODMR materials with color centers (such as SiC color centers, or color centers of ZnO, GaN, Si, organic matter, etc.) may be used instead. In addition, the high-frequency power supply 1 generates microwave currents of frequencies corresponding to the respective color centers.

[0135] In addition, in the above embodiment, the high-frequency magnetic field generating device can form a uniform magnetic field in an area substantially equal to the opening area of ​​the coil. Therefore, in the high-frequency region above 100 MHz, although it is suitable for ODMR, it can also be applied to other measurements using electron spin resonance such as EDMR. Fig.19 1 is a diagram showing the simulation results of the magnetic field generated by the high-frequency magnetic field generating device according to the sixth embodiment of the present invention. In this simulation, a current of about 3 GHz is supplied from a power supply to coils L1 and L2. As a result, Fig.19 As shown, a uniform magnetic field is generated in substantially the entire region of the opening area from the center of the coils L1 and L2 (for example, a region having a 10% error from the center value of the magnetic field intensity).

[0136] Furthermore, in the region of 100 MHz or less, the high-frequency magnetic field generating device according to each embodiment of the present invention can be used in the same manner as a conventional coil type oscillator.

[0137] (Industrial Applicability)

[0138] The present invention can be applied to, for example, a high-frequency magnetic field generating device for optically detecting magnetic resonance.

Claims

1. A high frequency magnetic field generating device, It is characterized in that have: Two coils are arranged in parallel with each other at a predetermined interval so as to sandwich the electron spin resonance material, or are arranged in parallel with each other at a predetermined interval on one side of the electron spin resonance material; a high frequency power source that generates microwave currents that are conducted to the two coils; as well as a transmission line portion connected to the two coils, A standing wave is formed in the two coils and the transmission line section, and the transmission line section sets a current distribution in such a way that the two coils are located at positions other than nodes of the standing wave; The high-frequency magnetic field generating device further comprises a substrate, The two coils are arranged on one surface of the substrate in a substantially vertical manner; The transmission line section includes two transmission lines. The two line bodies constituting the two transmission lines are line members each having a cutout ring shape, and are arranged on the other surface of the substrate in a substantially vertical manner.

2. A high frequency magnetic field generating device, It is characterized in that have: Two coils are arranged in parallel with each other at a predetermined interval so as to sandwich the electron spin resonance material, or are arranged in parallel with each other at a predetermined interval on one side of the electron spin resonance material; a high frequency power source that generates microwave currents that are conducted to the two coils; as well as a transmission line portion connected to the two coils, A standing wave is formed in the two coils and the transmission line section, and the transmission line section sets a current distribution in such a way that the two coils are located at positions other than nodes of the standing wave; The high-frequency magnetic field generating device further comprises a substrate, The two coils are arranged on one surface of the substrate in a substantially vertical manner; The transmission line section includes two transmission lines. The two line bodies constituting the two transmission lines are line members in the shape of cutout rings, and are arranged on the one surface of the substrate in a substantially vertical manner, and, The two line bodies constituting the two transmission lines are respectively arranged substantially perpendicular to the magnetic field formed by the two coils.

3. The high frequency magnetic field generating device according to claim 2, It is characterized in that The two coils are arranged between two line bodies constituting the two transmission lines and the substrate.

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