阅读说明：本技术 磁场测量装置及磁场测量方法 (Magnetic field measuring device and magnetic field measuring method ) 是由 芳井义治 水落宪和 于 2019-07-01 设计创作，主要内容包括：本发明提供一种利用ODMR准确地测量低频的交流磁场的磁场测量装置及磁场测量方法；线圈(2)对被配置于被测量交流磁场内的光探测磁共振部件(1)外加微波的磁场；高频电源(3)使微波的电流导通于线圈(2)；照射装置(4)对光探测磁共振部件(1)照射光；受光装置(5)探测从光探测磁共振部件(1)发出的光；而且,测量控制部(21)执行相对于被测量交流磁场的规定相位的规定的直流磁场测量序列,在该直流磁场测量序列中,对高频电源(3)以及照射装置(4)进行控制,确定由受光装置(5)探测出的光的探测光量；磁场运算部(22)根据该规定相位以及探测光量,对被测量交流磁场的强度进行运算。(The invention provides a magnetic field measuring device and a magnetic field measuring method for accurately measuring a low-frequency alternating current magnetic field by using ODMR; a coil (2) for applying a magnetic field of a microwave to a photodetection magnetic resonance component (1) disposed in an alternating-current magnetic field to be measured; a high-frequency power supply (3) conducts the current of the microwave to the coil (2); an irradiation device (4) irradiates the photodetection magnetic resonance component (1) with light; a light receiving device (5) that detects light emitted from the light detection magnetic resonance component (1); the measurement control unit (21) executes a predetermined DC magnetic field measurement sequence of a predetermined phase with respect to the AC magnetic field to be measured, and controls the high-frequency power supply (3) and the irradiation device (4) to determine the detection light amount of the light detected by the light receiving device (5); a magnetic field calculation unit (22) calculates the intensity of the AC magnetic field to be measured on the basis of the predetermined phase and the amount of the detected light.)

1. A magnetic field measuring device is characterized in that,

the disclosed device is provided with: a photodetection magnetic resonance unit, a coil, a high-frequency power supply, an irradiation device, a light receiving device, a measurement control unit, and a magnetic field calculation unit,

the optical detection magnetic resonance component is configured in the measured alternating current magnetic field,

the coil applies microwave magnetic field to the optical detection magnetic resonance component,

the high-frequency power supply enables the current of the microwave to be conducted to the coil,

the irradiation means irradiates light to the photodetection magnetic resonance component,

the light receiving means detects light emitted from the light detecting magnetic resonance element,

the measurement control unit executes a predetermined direct-current magnetic field measurement sequence of a predetermined phase with respect to the alternating-current magnetic field to be measured, and controls the high-frequency power supply and the irradiation device to determine the detection light amount of the light detected by the light receiving device in the direct-current magnetic field measurement sequence,

the magnetic field calculation unit calculates the intensity of the ac magnetic field to be measured based on the predetermined phase and the amount of the detection light.

2. Magnetic field measurement device according to claim 1,

the measurement control unit executes the following processing: (a) performing the dc magnetic field measurement sequence at a defined first phase with respect to the measured ac magnetic field, (b) performing the dc magnetic field measurement sequence at a defined second phase with respect to the measured ac magnetic field;

the magnetic field calculation unit calculates the intensity of the alternating-current magnetic field to be measured based on a difference between a magnetic flux density in the first phase and a magnetic flux density in the second phase from the first phase, the second phase, and the amount of detected light with respect to the first phase and the second phase;

the absolute value of the difference between the first phase and pi/2 and the absolute value of the difference between the second phase and 3 pi/2 are substantially the same as each other.

3. Magnetic field measurement device according to claim 1,

the measurement control unit executes the dc magnetic field measurement sequence for a predetermined plurality of phases of the ac magnetic field to be measured;

the magnetic field calculation unit calculates the intensity of the ac magnetic field to be measured based on the average value of the magnetic field intensities obtained in the dc magnetic field measurement sequence for the plurality of phases, using the average value of the plurality of phases as the predetermined phase.

4. A magnetic field measuring method is characterized in that,

(a) executing a predetermined direct-current magnetic field measurement sequence of a predetermined phase with respect to the alternating-current magnetic field to be measured using an optical detection magnetic resonance unit disposed in the alternating-current magnetic field to be measured, a coil for applying a magnetic field of a microwave to the optical detection magnetic resonance unit, a high-frequency power supply for conducting a current of the microwave to the coil, an irradiation device for irradiating the optical detection magnetic resonance unit with light, and a light receiving device for detecting light emitted from the optical detection magnetic resonance unit, wherein the direct-current magnetic field measurement sequence is such that the high-frequency power supply and the irradiation device are controlled to determine a detection light amount of the light detected by the light receiving device,

(b) the intensity of the alternating-current magnetic field to be measured is calculated based on the predetermined phase and the amount of the detection light.

Technical Field

The present invention relates to a magnetic field measuring apparatus and a magnetic field measuring method.

Background

Some Magnetic measurement devices perform Magnetic measurement by Optical Detection Magnetic Resonance (ODMR) using electron spin Resonance (see, for example, patent document 1).

In ODMR, a high-frequency magnetic field (microwave) and light are irradiated to a medium having a sub-level and an optical transition level for excitation between sub-levels and excitation between optical transitions, respectively, so that a change in an occupied number or the like due to magnetic resonance between sub-levels is detected with high sensitivity using an optical signal. Generally, electrons in the ground state are excited by green light, and then emit red light when returning to the ground state. On the other hand, for example, electrons in a Nitrogen Vacancy Center (NVC) in a diamond structure are initialized by light excitation by irradiation with a high-frequency magnetic field of about 2.87GHz, and then transition from the lowest energy level (ms ═ 0) of the three sublevels in the ground state to an energy level (ms ═ ± 1) of an energy orbit higher than the lowest energy level in the ground state. When the electrons in this state are excited by green light, the amount of light emission is reduced in order to return to the lowest level (ms is 0) of the three sub-levels in the ground state without radiation, and by this photodetection, it is possible to know whether or not magnetic resonance is caused by a high-frequency magnetic field. In ODMR, light such as NVC above is used to probe magnetic resonance materials.

Further, as a method for measuring a dc magnetic field using NVC, there is a method for measuring using a lamb-sync Pulse Sequence (Ramsey Pulse Sequence). In the lamb wave pulse train, (a) the NVC is irradiated with excitation light, (b) the first pi/2 pulse of the microwave is applied to the NVC, (c) the second pi/2 pulse of the microwave is applied to the NVC at a predetermined time interval tt from the first pi/2 pulse, (d) the NVC is irradiated with measurement light and the amount of luminescence of the NVC is measured, and (e) the magnetic flux density is estimated based on the amount of luminescence measured.

As a method for measuring an ac magnetic field using NVC, there is a method using a Spin Echo Pulse Sequence (Spin Echo Pulse Sequence). In the spin echo pulse sequence, (a) the NVC is irradiated with excitation light, (b) the first pi/2 pulse of the microwave is applied to the NVC at a phase of 0 degree of the magnetic field to be measured, (c) the pi pulse of the microwave is applied to the NVC at a phase of 180 degree of the magnetic field to be measured, (d) the second pi/2 pulse of the microwave is applied to the NVC at a phase of 360 degree of the magnetic field to be measured, (e) the NVC is irradiated with measurement light and the amount of luminescence of the NVC is measured, and (f) the magnetic flux density is estimated based on the amount of luminescence measured.

[ Prior art documents ]

[ patent document ]

Patent document 1: japanese laid-open patent publication (Kokai) No. 2012-110489

However, in the spin echo pulse sequence, if the time interval between the first pi/2 pulse and the pi pulse and the time interval between the pi pulse and the second pi/2 pulse become longer, the spin of electrons in the photodetection magnetic resonance material whose spin state is aligned by the excitation light is excessively dispersed, and therefore it is difficult to accurately measure the low-frequency ac magnetic field having a long wavelength.

Disclosure of Invention

The invention aims to obtain a magnetic field measuring device and a magnetic field measuring method for accurately measuring a low-frequency alternating magnetic field by using ODMR.

The magnetic field measuring apparatus according to the present invention comprises a photodetection magnetic resonance element, a coil, a high-frequency power supply, an irradiation device, a light receiving device, a measurement control unit, and a magnetic field calculation unit, wherein the photodetection magnetic resonance unit is disposed in the AC magnetic field to be measured, the coil applies a magnetic field of a microwave to the photodetection magnetic resonance unit, the high-frequency power supply conducts a current of the microwave to the coil, the irradiation device irradiates the photodetection magnetic resonance unit with light, the light-receiving device detects light emitted from the photodetection magnetic resonance unit, the measurement control unit executes a predetermined DC magnetic field measurement sequence of a predetermined phase with respect to the AC magnetic field to be measured, and in the DC magnetic field measurement sequence, a magnetic field calculation unit calculates the intensity of an AC magnetic field to be measured based on a predetermined phase and the amount of detected light.

The magnetic field measuring method according to the present invention (a) executes a predetermined dc magnetic field measurement sequence of a predetermined phase with respect to an ac magnetic field to be measured using a photodetection magnetic resonance element disposed in the ac magnetic field to be measured, a coil for applying a magnetic field of a microwave to the photodetection magnetic resonance element, a high-frequency power supply for supplying a current of the microwave to the coil, an irradiation device for irradiating the photodetection magnetic resonance element with light, and a light receiving device for detecting light emitted from the photodetection magnetic resonance element, and (b) determines a detection light amount of the light detected by the light receiving device by controlling the high-frequency power supply and the irradiation device in the dc magnetic field measurement sequence, and calculates the intensity of the ac magnetic field to be measured based on the predetermined phase and the detection light amount.

(effect of the invention)

According to the present invention, a magnetic field measuring apparatus and a magnetic field measuring method for accurately measuring a low-frequency ac magnetic field by using ODMR can be obtained.

Drawings

Fig. 1 is a diagram showing a configuration of a magnetic field measuring apparatus according to an embodiment of the present invention.

Fig. 2 is a timing chart illustrating an operation of the magnetic field measuring apparatus according to the first embodiment.

Fig. 3 is a timing chart illustrating an operation of the magnetic field measuring apparatus according to the second embodiment.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings.