JP7112652B2 - High frequency magnetic field generator - Google Patents

Description

The present invention relates to a high frequency magnetic field generator.

In Optically Detected Magnetic Resonance (ODMR), a medium with sub-level levels and optical transition levels is simultaneously irradiated with a high-frequency magnetic field (microwave) and light to generate magnetic resonance between sub-levels. A change in the number of occupancies due to the light signal is detected with high sensitivity.

Normally, ground-state electrons emit red light when returning to the ground state after being excited by green light. On the other hand, for example, nitrogen in the diamond structure and electrons in lattice defects (NVC: Nitrogen Vacancy Center) are at the lowest level among the three sublevels in the ground state by irradiation with a high frequency magnetic field around 2.87 GHz. (m _s =0) to higher energy orbital levels (m _s =±1) in the ground state. When the electrons in that state are excited by green light, they return to the lowest level (m _s =0) among the three sublevels in the ground state without radiation, so the amount of light emitted decreases. It is possible to know whether or not magnetic resonance has occurred due to the high-frequency magnetic field. ODMR uses such a light-detecting magnetic resonance material, such as NVC.

In one measurement system, a split-ring resonator or a coil or wire antenna is installed under a diamond sample, and a high-frequency magnetic field in the microwave region around 2.87 GHz is applied from the resonator to the sample. Information of cells near the diamond structure described above is obtained by sweeping the irradiated, high-frequency magnetic field and excitation light and detecting the depletion point of red light from the electrons with a detector (e.g., non-patented Reference 1).

Also, a certain magnetic measurement device performs magnetic measurement by ODMR using electron spin resonance (see Patent Document 1, for example). Also in this magnetic measurement device, a magnetic field of microwaves is generated by one coil.

JP 2012-110489 A

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)

However, the coils and antennas described above can generate a three-dimensionally uniform high-frequency magnetic field only in a very narrow range, making it difficult to increase the detection sensitivity of the ODMR. For example, in the case of Non-Patent Document 1, as shown in FIG. 20, a circular copper plate ring antenna type resonator having a radius R (about 7 mm) is used, and a slit is formed in the center thereof. A through hole with a radius of r (about 0.5 mm) is formed at the tip of the slit. When a current of about 2.87 GHz is applied from a high-frequency power source, a uniform magnetic field can be generated in a region with a radius of about 1 mm from the circle, as shown in FIG. In 98% of the area, the strength of the magnetic field tapers off from the center of the coil and becomes unusable for ODMR detection. Note that other measurements using electron spin resonance, such as electrically detected magnetic resonance (EDMR), have similar problems.

The present invention has been made in view of the above problems, and generates a substantially uniform high-frequency magnetic field in a three-dimensional wide range, and a high-frequency magnetic field that can increase the detection sensitivity in measurement using electron spin resonance. The object is to obtain a generator.

A high-frequency magnetic field generator according to the present invention includes two coils arranged parallel to each other at a predetermined interval so as to sandwich an electron spin resonance material or on one side of the electron spin resonance material, and the two coils are electrically connected. A high-frequency power source for generating a microwave current to generate a current, and a transmission line section connected to the two coils. Then, a standing wave is formed in the two coils and the transmission line section, and the transmission line section sets the current distribution such that the two coils are positioned outside the node of the standing wave. do.

Further, the high-frequency magnetic field generator according to the present invention includes a high-frequency power supply, at least two pairs of coils, a transmission line between one of the two pairs of coils, and the other coil of the two pairs of coils. and at least two transmission lines, including a transmission line between. A radio frequency power source produces a microwave current that conducts through two respective pairs of the at least two pairs of coils. Each pair of the at least two pairs of coils is arranged in parallel with each other at a predetermined interval so as to sandwich the electron spin resonance material or on one side of the electron spin resonance material . A standing wave is formed in each pair of coils in the coil and the transmission line section. Then , the at least two transmission lines set the current distribution such that each coil of the at least two pairs of coils is located outside the node of the standing wave.

Further, a high-frequency magnetic field generator according to the present invention includes a substrate, a through hole in the substrate, a plate-like coil arranged in the through-hole, a high-frequency power source that generates a microwave current conducting to the plate-like coil, and a transmission line portion connected to the plate-like coil. Then, a standing wave is formed in the plate-like coil and the transmission line section, and the transmission line section sets the current distribution such that the plate-like coil is located outside the node of the standing wave. The longitudinal direction of the cross section of the plate-like coil is the height direction of the plate-like coil and the vertical direction of the substrate. The book functions as two coils placed parallel to each other with a predetermined spacing between them, or on one side of the electron spin resonant material.

According to the present invention, it is possible to obtain a high-frequency magnetic field generator that can generate a substantially uniform high-frequency magnetic field over a three-dimensionally wide range and that can increase the detection sensitivity in measurement using electron spin resonance.

FIG. 1 is a perspective view illustrating the arrangement of coils in a high-frequency magnetic field generator according to an embodiment of the present invention. FIG. 2 is a circuit diagram showing the configuration of the high-frequency magnetic field generator according to Embodiment 1 of the present invention. FIG. 3 is a circuit diagram showing the configuration of a high-frequency magnetic field generator according to Embodiment 2 of the present invention. FIG. 4 is a circuit diagram showing the configuration of a high-frequency magnetic field generator according to Embodiment 3 of the present invention. FIG. 5 is a circuit diagram showing the configuration of a high-frequency magnetic field generator according to Embodiment 4 of the present invention. FIG. 6 is a perspective view illustrating an example of arrangement of coils in a high-frequency magnetic field generator according to Embodiment 4 of the present invention. FIG. 7 is a perspective view illustrating a coil and a line body in a high-frequency magnetic field generator according to Embodiment 5 of the present invention. FIG. 8 is a perspective view illustrating coils and a line body in a high-frequency magnetic field generator according to Embodiment 6 of the present invention. FIG. 9 is a perspective view showing another example of the line body in the high-frequency magnetic field generator according to Embodiment 6 of the present invention. FIG. 10 is a perspective view illustrating coils and a line body in a high-frequency magnetic field generator according to Embodiment 7 of the present invention. FIG. 11 is a circuit diagram showing the configuration of a high-frequency magnetic field generator according to Embodiment 8 of the present invention. FIG. 12 is a circuit diagram showing the configuration of a high-frequency magnetic field generator according to Modification 1 of Embodiment 8 of the present invention. FIG. 13 is a circuit diagram showing the configuration of a high-frequency magnetic field generator according to Modification 2 of Embodiment 8 of the present invention. FIG. 14 is a circuit diagram showing the configuration of a high-frequency magnetic field generator according to Embodiment 9 of the present invention. FIG. 15 is a circuit diagram showing the configuration of a high-frequency magnetic field generator according to Embodiment 10 of the present invention. FIG. 16 is a diagram showing the configuration of a high-frequency magnetic field generator according to Embodiment 11 of the present invention. FIG. 17 is a diagram showing the configuration of a high-frequency magnetic field generator according to Embodiment 12 of the present invention. FIG. 18 is a diagram showing the configuration of a high-frequency magnetic field generator according to Embodiment 13 of the present invention. FIG. 19 is a diagram showing simulation results of the magnetic field emitted from the high-frequency magnetic field generator according to Embodiment 6 of the present invention. FIG. 20 is a circuit diagram showing the configuration of a conventional coil-type high frequency generator. FIG. 21 is a diagram showing a magnetic field emitted from a conventional coil-type high-frequency generator.

Embodiments of the present invention will be described below based on the drawings.

Embodiment 1.

FIG. 1 is a perspective view illustrating the arrangement of coils in a high-frequency magnetic field generator according to an embodiment of the present invention.

A high-frequency magnetic field generator according to an embodiment of the present invention includes at least two coils L1 and L2. As shown in FIG. 1, 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). A sample 101 is placed on a plate 102 such as diamond having NVC as an optical detection magnetic resonance material (hereinafter referred to as an ODMR material), and the plate 102 is fixed to a sample plate 103 . The two coils L1 and L2 are arranged with a plate member 102 having NVC as an ODMR material sandwiched therebetween. Note that the ODMR material is a kind of electron spin resonance material.

The two coils L1 and L2 have the same shape and are arranged to have the same center axis. Also, here, the number of turns of each of the coils L1 and L2 is approximately one turn (less than one turn). A microwave current is conducted through the two coils L1 and L2, and the two coils L1 and L2 each generate an alternating magnetic field as microwaves in phase (that is, in the same direction at each point in time). This alternating magnetic field is applied to the ODMR material, and a static magnetic field (not shown) is applied separately from the alternating magnetic field generated by the coils L1 and L2. Then, an optical system (not shown) irradiates the ODMR material with measurement light such as a laser beam of a predetermined wavelength, and for example, by observing radiation light of a specific wavelength, measurement based on photodetection magnetic resonance (magnetic measurement, NVC, etc.) orientation, temperature of NVC, etc.) are performed.

FIG. 2 is a circuit diagram showing the configuration of the high-frequency magnetic field generator according to Embodiment 1 of the present invention.

As shown in FIG. 2, the high-frequency magnetic field generator according to Embodiment 1 further includes a high-frequency power supply 1 and two line bodies S1 and S2.

A high-frequency power supply 1 generates a microwave current that conducts through two coils L1 and L2. Specifically, the high-frequency power supply 1 generates microwave current in a band necessary for photodetection magnetic resonance (here, about 2.87 GHz).

The two line bodies S1 and S2 are transmission line sections connected to the two coils L1 and L2, respectively, and set the current distribution such that the two coils L1 and L2 are positioned outside the nodes of the standing wave. .

Each of the line bodies S1 and S2 may be configured as a single conductor line, or may be configured as a distributed constant circuit using resistor elements, capacitor elements, and the like.

Specifically, in Embodiment 1, as shown in FIG. 2, 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 open. It is connected to one end of each of the coils L1 and L2. The other ends of the two coils L1 and L2 are electrically connected to each other, and the high frequency power source 1 is connected to the connection point. Therefore, microwave current flows from the high-frequency power supply 1 to the other ends of the two coils L1 and L2. The two coils L1 and L2 have the same shape, and the line bodies S1 and S2 also have the same shape. By doing so, the coil L1 and the line body S1 and the coil L2 and the line body S2 have the same high frequency characteristics (that is, the same electrical length) as viewed from the high frequency power supply 1 .

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 is the wavelength of the microwave), the current distribution is as shown in FIG. , the coils L1 and L2 are located near the antinodes of the standing wave, not the nodes of the standing wave, and sufficient microwave current flows through the coils L1 and L2 to induce a microwave magnetic field.

For example, when the high-frequency power supply 1 generates microwaves of 2.87 GHz, the wavelength is about 10 cm. 5 cm. In order to facilitate tuning, the lengths of the coils L1 and L2 are preferably set to 1/2 or less of the lengths of the line bodies S1 and S2.

Next, operation of the high-frequency magnetic field generator according to Embodiment 1 will be described.

When the high-frequency power supply 1 generates microwave AC power, the microwave current travels through the coil L1 and the line body S1, and the coil L2 and the line body S2. Here, since impedance matching is not performed at the end of the coil L1 and line body S1 and at the end of the coil L2 and line body S2, the coil L1 and line body S1 and the coil L2 and line body S2 are shown in FIG. A standing wave is formed as shown.

As a result, alternating currents of the same phase and magnitude are conducted to the coils L1 and L2. A microwave magnetic field is generated by currents conducted in the coils L1 and L2. Since the coils L1 and L2 are arranged coaxially and substantially parallel, in the space between the coils L1 and L2, the directions of the magnetic fields are substantially parallel to the central axes of the coils L1 and L2, and the magnetic fields are substantially uniform. like.

As described above, according to the first embodiment, the two coils L1 and L2 are arranged parallel to each other with the ODMR material interposed therebetween at a predetermined interval. A high-frequency power supply 1 generates a microwave current that conducts through its 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.

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

In this embodiment, one end of each of the line bodies S1 and S2 is open. A circuit may be connected.

Also, as shown in FIG. 1, the two coils L1 and L2 are arranged parallel to each other with the ODMR material sandwiched therebetween, but the ODMR material is arranged on one side of the two coils L1 and L2. You may do so. In this case, although the resonance band becomes a little narrower, there is an advantage that the degree of freedom in setting the ODMR material increases.

In FIG. 1, the plate member 102 and the sample plate 103 are arranged perpendicular to the direction of the magnetic field (the direction of the central axes of the coils L1 and L2). (The direction of the central axis of the coils L1 and L2) may be inclined, and a uniform magnetic field is applied to the plate member 102 even in that case.

Embodiment 2.

FIG. 3 is a circuit diagram showing the configuration of a high-frequency magnetic field generator according to Embodiment 2 of the present invention. The high-frequency magnetic field generator according to the second embodiment has the same configuration as the high-frequency magnetic field generator according to the first embodiment, and further includes an impedance matching section 11 between the high-frequency power supply 1 and the two coils L1 and L2. Prepare.

If there is no impedance matching between the high-frequency power supply 1 and the coils L1 and L2, the microwaves from the high-frequency power supply 1 are reflected by the coils L1 and L2, and the microwaves are not sufficient for the coils L1 and L2. An impedance matching unit 11 is provided when impedance matching is not achieved between the high-frequency power source 1 and the coils L1 and L2 because no current flows. As a result, impedance matching is achieved, and microwaves from the high frequency power supply 1 propagate 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 thereof is used.

In FIG. 3, the impedance matching section 11 is arranged between the connection point of the coil L1 and the coil L2 and the high-frequency power supply 1. and between the coil L2 and the high-frequency power source 1, respectively.

Further, it is of course possible to provide a similar impedance matching section in a high-frequency magnetic field generator according to another embodiment described later. At that time, when the high-frequency power supply 1 and two line bodies are connected, a similar impedance matching section may be provided between the high-frequency power supply 1 and the two line bodies.

As described above, according to the second embodiment, impedance matching can be achieved even when impedance matching cannot be achieved only with the coils L1 and L2 and the line bodies S1 and S2.

Embodiment 3.

FIG. 4 is a circuit diagram showing the configuration of a high-frequency magnetic field generator according to Embodiment 3 of the present invention. The high-frequency magnetic field generator according to Embodiment 3 includes at least two pairs of coils (L1-i, L2-i) (i=1, . . . , n; n>1), and each of the two pairs of coils At least two line bodies S1-j and S2-j including a line body S1-j between one coil L1-i and a line body S2-j between the other coils L2-i of the two pairs of coils and

In Embodiment 3, the high-frequency power supply 1 includes two coils L1-i that are pairs of the at least two pairs of coils (L1-i, L2-i) (i=1, . . . , n) described above. , L2-i.

Each pair of the at least two pairs of coils (L1-i, L2-i) mentioned above are arranged parallel to each other with a predetermined spacing between the ODMR materials. For example, the coils L1-1 to L1-n are arranged so that the magnetic fields of the induced microwaves are in phase, and the coils L2-1 to L2-n are arranged so that the magnetic fields of the induced microwaves are in phase. placed in That is, the magnetic fields of the microwaves induced by the coils L1-1 to L1-n and L2-1 to L2-n are in the same direction.

Further, the at least two line bodies S1-j and S2-j set the current distribution such that each of the at least two pairs of coils L1-i and L2-i is located outside the node of the standing wave. This is the transmission line section that For example, all the line bodies S1-j and S2-j have the same electrical length, the line bodies S1-j and the coils L1-j are arranged alternately, and the line bodies S2-j and the coils L2-j are arranged alternately. 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). The ends of the intermediate and terminal line bodies S1-n and S2-n are respectively open.

For example, the coils L1-i and L2-i have the same shape and are arranged to have the same center axis. Here, the number of turns of each coil L1-i, L2-i is approximately 1 turn (less than 1 turn), the electrical length of the coils L1-1 to L1-n and the line body S1-j therebetween, and When the electrical length of the coils L2-1 to L2-n and the line body S2-j between them is (2n-1)λ/4, the current distribution is as shown in FIG. L1-i and L2-i are located at positions other than nodes of the standing wave, sufficient microwave currents flow through the coils L1 and L2, and microwave magnetic fields are induced.

As described above, according to the third embodiment, since the number of coils L1-i and L2-i is large, the strength of the induced high-frequency magnetic field can be increased.

Embodiment 4.

FIG. 5 is a circuit diagram showing the configuration of a high-frequency magnetic field generator according to Embodiment 4 of the present invention. As shown in FIG. 5, the high-frequency magnetic field generator according to Embodiment 4 includes two pairs of coils (L11, L21) and (L12, L22) and two line bodies S11 and S21 as transmission line sections. Prepare.

FIG. 6 is a perspective view illustrating an example of arrangement of coils L11, L12, L21, and L22 in the high-frequency magnetic field generator according to Embodiment 4 of the present invention. As shown in FIG. 6, the number of turns of each of the coils L11, L21, L12, and L22 is approximately half a turn. L12 and coil L21 form a pair and induce microwave magnetic fields in phase.

The number of turns of each of the coils L11, L21, L12, and L22 is approximately one turn as in the first to third embodiments, and the in-phase coils L11 and L22 are arranged close to each other (that is, approximately two turns in total). ), and in-phase coils L12 and L21 may be arranged close to each other.

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. , The other ends of the two line bodies S11 and S21 are connected to one ends of the two coils L11 and L21, 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 at . Then, microwave current flows from the high-frequency power supply 1 through the coils L11 and L21 into the other ends of the two line bodies S11 and S21. Therefore, one end (short-circuited end) of the coils L12 and L22 becomes an antinode of the current distribution, and the coils L11, L12, L21 and L22 are located outside the nodes of the current distribution as shown in FIG.

Embodiment 5.

FIG. 7 is a perspective view illustrating a coil and a line body in a high-frequency magnetic field generator according to Embodiment 5 of the present invention.

A high-frequency magnetic field generator according to Embodiment 5 has a circuit configuration as shown in Embodiment 1 or Embodiment 2 (FIG. 2 or FIG. 3) and includes substrate 21 . The two coils L1 and L2 are arranged on one surface of the substrate 21 substantially perpendicular to that surface. Further, in the fifth embodiment, the two line bodies S1 and S2 are line members each having a notched ring shape, and are arranged on the other surface of the substrate 21 substantially perpendicularly to that surface.

2 or 3, the coils L1 and L2, the line bodies S1 and S2, and the high-frequency power source 1 are electrically connected. by Hall, etc.

The operation of the high-frequency magnetic field generator according to Embodiment 5 is the same as that of Embodiment 1 or Embodiment 2, so the description thereof will be omitted.

Embodiment 6.

FIG. 8 is a perspective view illustrating coils and a line body in a high-frequency magnetic field generator according to Embodiment 6 of the present invention.

A high-frequency magnetic field generator according to Embodiment 6 has a circuit configuration as shown in Embodiment 1 or Embodiment 2 (FIG. 2 or FIG. 3) and includes substrate 21 . The two coils L1 and L2 are arranged on one surface of the substrate 21 substantially perpendicular to that surface. Further, in the sixth embodiment, the two line bodies S1 and S2 are wiring patterns, respectively, and are formed on either surface of the substrate 21. As shown in FIG.

FIG. 9 is a perspective view showing another example of the line body in the high-frequency magnetic field generator according to Embodiment 6 of the present invention. As shown in FIG. 9, the same branch paths 31 and 32 may be provided on the line bodies S1 and S2, respectively. By doing so, it is possible to adjust the current distribution in the coils L1, L2 and the line bodies S1, S2, and also to adjust the width of the input band.

The operation of the high-frequency magnetic field generator according to Embodiment 6 is the same as that of Embodiment 1 or Embodiment 2, so description thereof will be omitted.

Embodiment 7.

FIG. 10 is a perspective view illustrating coils and a line body in a high-frequency magnetic field generator according to Embodiment 7 of the present invention.

A high-frequency magnetic field generator according to Embodiment 7 has a circuit configuration as shown in Embodiment 4 (FIG. 5) and includes substrate 21 . As shown in FIG. 10, in Embodiment 7, coils L11, L12, L21, and L22 are arranged on a substrate 21 perpendicularly to the substrate 21, and one end of the coil L11 and one end of the coil L12 are notched. A ring-shaped line body S11 is connected, and a notched ring-shaped line body S21 is connected to one end of the coil L21 and one end of the coil L22.

As shown in FIG. 10, the line bodies S11 and S21 are arranged with respect to the opening direction of the coils L11 and L22 and the opening direction of the coils L12 and L21 (that is, the direction of the magnetic field formed by the coils L11, L22, L12 and L21). The coils L11, L22, L12, L21 and the line bodies S11, S21 are less likely to be magnetically coupled.

Since the operation of the high-frequency magnetic field generator according to Embodiment 7 is the same as that of Embodiment 4, the explanation thereof will be omitted.

Embodiment 8.

FIG. 11 is a circuit diagram showing the configuration of a high-frequency magnetic field generator according to Embodiment 8 of the present invention.

In the high-frequency magnetic field generator according to the eighth embodiment, as shown in FIG. 11, two coils L1 and L2 are connected in parallel, and a connection point between the two coils L1 and L2 is provided with one transmission line as a transmission line section. A line S1s is connected. In the eighth embodiment, one transmission line S1s sets the current distribution such that the two coils L1 and L2 are located outside the node of the standing wave.

Specifically, in the eighth embodiment, as shown in FIG. 11, one end of the line body S1s is open, and the other end of the line body S1s is connected to one connection point of the two coils L1 and L2. ing. A high-frequency power source 1 is connected to the other connection point of the two coils L1 and L2. Therefore, microwave current flows from the high-frequency power supply 1 to the other ends of the two coils L1 and L2. The two coils L1 and L2 have the same shape, and the line bodies S1 and S2 also have the same shape. By doing so, the coil L1 and the line body S1 and the coil L2 and the line body S2 have the same high frequency characteristics (that is, the same electrical length) as viewed from the high frequency power supply 1 .

For example, when the electrical lengths of the coils L1 and L2 and the line body S1s are λ/4 (λ is the wavelength of the microwave), the current distribution is as shown in FIG. , near the antinodes of the standing wave, rather than the nodes of the standing wave, sufficient microwave current flows through the coils L1 and L2 to induce a microwave magnetic field.

Since the operation of the high-frequency magnetic field generator according to Embodiment 8 is the same as that of Embodiment 1, the explanation thereof will be omitted.

12 or 13 may be adopted for the configuration of the high-frequency magnetic field generator according to the eighth embodiment shown in FIG.

FIG. 12 is a circuit diagram showing the configuration of a high-frequency magnetic field generator according to Modification 1 of Embodiment 8 of the present invention. In Modification 1 shown in FIG. 12, one end of the variable capacitance element 41 is connected to one end of the line body S1s that is not connected to the coils L1 and L2, and the other end of the variable capacitance element 41 is grounded. As a result, even if there is a deviation from the central axis, the center of the resonance frequencies of the coils L1 and L2 can be adjusted to be as close as possible to the desired frequency by varying the capacitance of the variable capacitance element 41. can be done. Also, the variable capacitance element 41 may have a very small electrostatic capacitance value, and may be a movable device that slightly moves the position of a part of the line body S1s, for example. Alternatively, the variable capacitive element 41 may be a movable capacitor having minute electrostatic capacity, for example.

FIG. 13 is a circuit diagram showing the configuration of a high-frequency magnetic field generator according to Modification 2 of Embodiment 8 of the present invention. In Modification 2 shown in FIG. 13, one end of the variable capacitance element 51 is connected to the other end of the line body S1s not connected to the coils L1 and L2 (that is, to the power supply side), and the other end of the variable capacitance element 51 is grounded. As a result, as in Modification 1 described above, even if the coils L1 and L2 change in shape or are deviated from the central axis, the capacitance of the variable capacitive element 51 is changed so that the coil L1 and L2 can be adjusted so that the centers of the resonance frequencies are as close to the desired frequency as possible. In addition, the variable capacitance element 51 may have a very small electrostatic capacitance value. It is good also as a device etc. which move.

Embodiment 9.

FIG. 14 is a circuit diagram showing the configuration of a high-frequency magnetic field generator according to Embodiment 9 of the present invention.

In the high-frequency magnetic field generator according to Embodiment 9, as shown in FIG. 14, two coils L1 and L2 are connected in parallel, and a connection point between the two coils L1 and L2 is provided with one transmission line as a transmission line section. A line S1s is connected. In the ninth embodiment, one transmission line S1s sets the current distribution so that the two coils L1 and L2 are located outside the node of the standing wave.

Specifically, in the ninth embodiment, as shown in FIG. 14, one end of the line body S1s is connected to the high-frequency power source 1 via the first impedance matching section 11, and the other end of the line body S1s is connected to the second end of the line body S1s. It is connected to one connection point of two coils L1 and L2. Also, one end of the second impedance matching section 11 is connected to the other connection point of the two coils L1 and L2. Furthermore, one end of the second impedance matching section 11 is open. Therefore, 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. The two coils L1 and L2 have the same shape, and the line bodies S1 and S2 also have the same shape. By doing so, the coil L1 and the line body S1 and the coil L2 and the line body S2 have the same high frequency characteristics (that is, the same electrical length) as viewed from the high frequency power supply 1 .

For example, when the electrical lengths of the coils L1 and L2 and the line body S1s are λ/4 (λ is the wavelength of the microwave), the current distribution is as shown in FIG. , near the antinodes of the standing wave, rather than the nodes of the standing wave, sufficient microwave current flows through the coils L1 and L2 to induce a microwave magnetic field.

Embodiment 10.

FIG. 15 is a circuit diagram showing the configuration of a high-frequency magnetic field generator according to Embodiment 10 of the present invention.

In the high-frequency magnetic field generator according to the tenth embodiment, as shown in FIG. 15, two coils L1 and L2 are connected in parallel, and a connection point between the two coils L1 and L2 is provided with a transmission line as a transmission line section. S1s are connected. In the tenth embodiment, one transmission line S1s sets the current distribution such that the two coils L1 and L2 are located outside the nodes of the standing wave.

Specifically, in the tenth embodiment, as shown in FIG. 15, one end of the first line body S1s is connected to the high-frequency power supply 1 via the first impedance matching section 11, and the first line body S1s The other end is connected to one connection point of the two coils L1 and L2. One end of the first line body S1s is connected to the other connection point of the two coils L1 and L2. Also, the other end of the first line body is connected to one end of the second impedance matching section 11 . Furthermore, one end of the second impedance matching section 11 is open. Therefore, microwave current flows from the high-frequency power supply 1 through the first impedance matching section 11 and the first line body S1s into one end of each of the two coils L1 and L2. The two coils L1 and L2 have the same shape, and the line bodies S1 and S2 also have the same shape. By doing so, the coil L1 and the line body S1 and the coil L2 and the line body S2 have the same high frequency characteristics (that is, the same electrical length) as viewed from the high frequency power supply 1 .

For example, when the electrical lengths of the coils L1 and L2 and the line body S1s are λ/2 (λ is the wavelength of the microwave), the current distribution is as shown in FIG. , near the antinodes of the standing wave, rather than the nodes of the standing wave, sufficient microwave current flows through the coils L1 and L2 to induce a microwave magnetic field.

Embodiment 11.

FIG. 16 is a diagram showing the configuration of a high-frequency magnetic field generator according to Embodiment 11 of the present invention.

In the eleventh embodiment, coils L1 and L2 are formed as mutually parallel metal patterns on the front and rear surfaces of a substrate 61 having a predetermined thickness. Further, a through hole 62 is provided through the center of the coils L1 and L2. This through-hole 62 allows the sample to be placed at any position between the coils L1 and L2, not only when both the pair of coils L1 and L2 are spaced apart by a predetermined distance on one side of the sample. A high-frequency alternating magnetic field can be applied to the sample even when

Further, as shown in FIG. 16, through holes 63 and 64 may be formed in the thickness of the substrate 61 and parallel to the radial direction of the coils L1 and L2. In that case, a laser beam is incident from the through-hole 63, the beam is irradiated to the sample (not shown) in the through-hole 62, and the reflected light passes through the through-hole 62 and is reflected in the vertical direction. detectable. On the other hand, out of the laser light, the light that has penetrated the sample is emitted from the through hole 64 . Therefore, the emitted light may be observed. Moreover, the diameter of the through-hole 64 may be made larger than the diameter of the through-hole 63 in consideration of the refraction of light.

Further, in the eleventh embodiment, since the substrate 61 is sandwiched between the coils L1 and L2, various mechanical aspects such as the stable shape formation of the coils L1 and L2 and the maintenance of a stable distance between them can be achieved. good normal and electrical performance.

Embodiment 12.

FIG. 17 is a diagram showing the configuration of a high-frequency magnetic field generator according to Embodiment 12 of the present invention.

The twelfth embodiment includes a plate-like coil La instead of the coils L1 and L2 described above in the eleventh embodiment. A through hole 82 is provided in a substrate 81 having a predetermined thickness. The plate-shaped coil La is arranged in the through hole. In the twelfth embodiment, the plate-like coil La is fixed on the inner wall of the substrate 81 facing the through hole 82 so that the longitudinal direction of the cross section of the plate-like coil La is perpendicular to the substrate 81 . The cross section of the plate-shaped coil La is substantially rectangular. The through hole 82 may be a through hole, and the plate-like coil La may be formed by bending a thin metal plate such as a copper plate. A metal foil formed by

Further, in the twelfth embodiment, the through hole 82 has an observation hole portion 82a having a circular cross section. Of the four edge portions LaEU and LaEL of the plate-like coil La (especially the edge portions in the observation hole portion 82a), one edge portion LaEU on the upper end side and one edge portion LaEL on the lower end side are electron It functions as two coils arranged parallel to each other at a predetermined interval so as to sandwich the spin resonance material or on one side of the electron spin resonance material. That is, due to the skin effect caused by high frequencies (particularly on the order of MHz or higher), the current flows intensively at the edge portions LaEU and LaEL of the plate-like coil La. and part LeEL function as separate coils. In order to make the layout similar to that of the Helmholtz coil, it is preferable that the height of the plate-like coil La (the length of the long side of the cross section) is substantially the same as the radius of the circular portion of the plate-like coil La. In addition, in order to suppress fluctuations in stray capacitance between the plate-like coil La and the lens barrel of the microscope, the width of the plate-like coil La (the short side length of the cross section) is sufficiently smaller than the height of the plate-like coil La. is preferred.

With this through hole 82, on one side of the sample, both the edge portion LaEU on the upper end side and the edge portion LaEL on the lower end side of the plate-like coil La are arranged apart from each other by a predetermined distance. A high-frequency alternating magnetic field can be applied to the sample even when the sample is placed at an arbitrary position between the upper edge portion LaEU and the lower edge portion LaUL of the shaped coil La.

Further, as shown in FIG. 17, through-holes 83 and 84 are formed in the thickness of the substrate 61 in parallel with the radial direction of the circular portion of the plate-like coil La. Through holes 85a and 85b for the coil La may be formed. In that case, the laser light is incident from the through hole 83 and the through hole 85a, the light is irradiated to the sample (not shown) in the through hole 82, and the reflected light passes through the through hole 82 and is reflected in the vertical direction. and can be detected with a microscope. On the other hand, out of the laser light, the light that has penetrated the sample is emitted from the through holes 85b and 84. As shown in FIG. Therefore, the emitted light may be observed. In consideration 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.

Other configurations and operations of the high-frequency magnetic field generator according to the twelfth embodiment are the same as those of the ninth and eleventh embodiments, or a combination thereof, and thus descriptions thereof will be omitted.

As described above, according to the twelfth embodiment, by applying the plate-like coil La described above, the DC resistance in the coil is reduced. In addition, if metallic objects such as the housing of a microscope for observation or dielectric objects such as a sample table exist around the coil, the resonance frequency due to the presence of such objects will fluctuate. However, by applying the above-described plate-shaped coil La, it is possible to suppress such fluctuations in the resonance frequency.

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 mm when the sample is placed in the through-hole 82. 96 GHz and 2.965 GHz with the microscope lens placed at a distance of 1.5 mm. On the other hand, in the comparative example, the frequency was 2.84 GHz when the sample was placed in the through hole, and 2.89 GHz when the microscope lens was placed at a distance of 1.5 mm. In this way, variations in resonance frequency are suppressed.

Embodiment 13.
FIG. 18 is a diagram showing the configuration of a high-frequency magnetic field generator according to Embodiment 13 of the present invention. In the thirteenth embodiment, the through hole 82 has a substantially rectangular shape, and the plate-like coil La is arranged inside the through hole 82 . In the thirteenth embodiment, plate-like coil La is fixed so as to protrude from the inner wall of substrate 81 facing through hole 82 .

Other configurations and operations of the high-frequency magnetic field generator according to the thirteenth embodiment are the same as those of the twelfth embodiment, so description thereof will be omitted.

Various changes and modifications to the above-described embodiments will be apparent to those skilled in the art. Such changes and modifications may be made without departing from the spirit and scope of its subject matter and without diminishing its intended advantages. It is therefore intended that such changes and modifications be covered by the claims.

For example, in the above embodiment, the two line bodies may be terminated with a predetermined resistance value without opening or short-circuiting the ends of the two line bodies.

Further, 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 high-frequency power source 1 may be connected to the connection point.

Further, in the above embodiments, the line body is used as the transmission line section, but the above-described line body may be replaced with a lumped constant circuit, if necessary.

Further, in the above embodiments, diamond having NVC is exemplified as the ODMR material, but other color centers (for example, SiC color centers, ZnO, GaN, Si, organic color centers, etc.) can be used instead. ODMR material may be used. The high-frequency power source 1 generates a microwave current having a frequency corresponding to each color center.

Further, in the above embodiment, the high-frequency magnetic field generator can form a uniform magnetic field in an area substantially equal to the open area of the coil. Therefore, especially in the high frequency region of 100 MHz or higher, although it is applied to ODMR, it may be applied to other measurements using electron spin resonance such as EDMR. FIG. 19 is a diagram showing simulation results regarding the magnetic field emitted from the high-frequency magnetic field generator according to Embodiment 6 of the present invention. This simulation was performed under the condition that a current of about 3 GHz was supplied from the power supply to the coils L1 and L2. As a result, as shown in FIG. have been shown to generate a uniform magnetic field (eg, regions with 10% error from the central value of the magnetic field strength).

Also, in the region of 100 MHz or less, the high-frequency magnetic field generators according to the embodiments of the present invention can be used in the same manner as the conventional coil-type oscillator.

The present invention is applicable, for example, to a high-frequency magnetic field generator for photodetection magnetic resonance.

1 high-frequency power supply 11 impedance matching part 21, 81 substrate 82 through hole L1, L2, L1-i, L2-i, L11, L12, L21, L22 coil La plate-like coil S1, S1s, S2, S11, S21 line body ( Example of transmission line section)

Claims (9)

two coils arranged parallel to each other at a predetermined interval so as to sandwich the electron spin resonance material or on one side of the electron spin resonance material;
a high frequency power source that generates a microwave current that conducts through the two coils;
a transmission line section connected to the two coils;
with
A standing wave is formed in the two coils and the transmission line section,
The transmission line section sets the current distribution such that the two coils are positioned outside the node of the standing wave;
A high-frequency magnetic field generator characterized by: The transmission line section is two transmission lines,
The two transmission lines are respectively connected to the two coils,
one end of each of the two transmission lines is open or connected to a circuit having a predetermined impedance at the same frequency,
The other end of each of the two transmission lines is connected to one end of each of the two coils,
the microwave current flowing from the high-frequency power supply to the other end of each of the two coils;
The high-frequency magnetic field generator according to claim 1, characterized by: The transmission line section is two transmission lines,
The two transmission lines are respectively connected to the two coils,
one end of each of the two coils is short-circuited;
The other end of each of the two coils is connected to one end of each of the two transmission lines,
the microwave current flowing from the high-frequency power supply to the other end of each of the two transmission lines;
The high-frequency magnetic field generator according to claim 1, characterized by: 4. The high-frequency magnetic field generator according to claim 1, further comprising an impedance matching section between the high-frequency power source and the two coils or the transmission line section. further comprising a substrate,
the two coils are arranged on one side of the substrate;
The transmission line portion is a notched ring-shaped line member and is arranged on the other surface of the substrate;
The high-frequency magnetic field generator according to claim 1, characterized by: further comprising a substrate,
each of the transmission line portions is a wiring pattern on the substrate;
The high-frequency magnetic field generator according to claim 1, characterized by: The transmission line section is one transmission line,
The two coils are connected in parallel,
The one transmission line is connected to a connection point of the two coils;
The high-frequency magnetic field generator according to claim 1, characterized by: a high frequency power supply;
at least two pairs of coils;
At least two transmission lines including a transmission line between one of the two pairs of coils and a transmission line between the other of the two pairs of coils,
The high-frequency power source generates a microwave current that conducts through two coils of each of the at least two pairs of coils;
each pair of the at least two pairs of coils are arranged parallel to each other with a predetermined spacing on either side of the electron spin resonant material or on one side of the electron spin resonant material;
standing waves are formed in each pair of coils in the at least two pairs of coils and in the transmission line section;
setting the current distribution of the at least two transmission lines so that each coil of the at least two pairs of coils is located outside a node of the standing wave;
A high-frequency magnetic field generator characterized by: a substrate;
a through hole in the substrate;
a plate-like coil arranged in the through hole;
a high-frequency power source that generates a microwave current that conducts to the plate-shaped coil;
A transmission line unit connected to the plate-shaped coil,
A standing wave is formed in the plate-like coil and the transmission line portion,
wherein the transmission line section sets a current distribution such that the plate-like coil is located outside the node of the standing wave;
the longitudinal direction of the cross section of the plate-like coil is the height direction of the plate-like coil and the vertical direction of the substrate;
Of the four edge portions of the plate-like coil, one on the upper end side and one on the lower end side are arranged at a predetermined interval so as to sandwich the electron spin resonance material or on one side of the electron spin resonance material. functioning as two coils arranged in parallel;
A high-frequency magnetic field generator characterized by:

Images