Physical quantity detecting device, physical quantity detecting method, and physical quantity detecting program

Abstract

The present invention enables an improvement in the detection accuracy of physical quantity detection employing a quantum sensor. A physical quantity detecting device 1 comprises a quantum sensor 2 having a spin defect 2a, an excitation unit 4 for imparting excitation energy to the spin defect 2a, an electromagnetic wave incidence unit 3 for causing a resonant electromagnetic wave for a ground state of the spin defect 2a and an electromagnetic wave for an excited state of the spin defect 2a to be incident on the spin defect 2a, and a light detecting unit 5 for detecting an intensity of light emitted by the spin defect 2a upon receipt of the excitation energy, the ground state resonant electromagnetic wave and the excited state electromagnetic wave, wherein a physical quantity is detected on the basis of the emitted light intensity detected by the light detecting unit 5.

Description

Physical quantity detection device, physical quantity detection method, and physical quantity detection program

[0001] The present invention relates to a physical quantity detection device, a physical quantity detection method, and a physical quantity detection program that detects a physical quantity using a quantum sensor.

[0002] Conventionally, a physical quantity detection device and a physical quantity detection method have been proposed that use a quantum sensor having a spin defect in a solid (such as an NV center-nitrogen-vacancy complex defect in diamond or a VSi-silicon vacancy defect in silicon carbide) to detect physical quantities such as magnetic field, strain, and temperature (see Patent Document 1).

[0003] In such a method for detecting a physical quantity using a quantum sensor having a VSi-monovacancy defect in silicon carbide, the emission intensity of the VSi-monovacancy defect changes depending on the physical quantity, and excitation energy and resonant electromagnetic waves are applied to the quantum sensor to detect a change in emission intensity upon resonance of the ground level or excited level of the VSi-monovacancy defect, thereby enabling the detection of the physical quantity.

[0004] However, physical quantity detection methods using quantum sensors with VSi-monovacancy defects in silicon carbide have a problem in that the change in emission intensity is low. In particular, the change in emission intensity at the excited level is very small, making it difficult to measure temperature using the excited level. In other words, conventional quantum sensors have a problem in that their sensitivity as sensors is very low, resulting in low detection accuracy (measurement accuracy) of physical quantities.

[0005] U.S. Pat. No. 1,052,9416

[0006] In view of the above-mentioned problems, an object of the present invention is to provide a physical quantity detection device, a physical quantity detection method, and a physical quantity detection program that can improve the detection accuracy of physical quantity detection using a quantum sensor.

[0007] The present invention is characterized by a physical quantity detection device, a physical quantity detection method, and a physical quantity detection program, each of which includes: a quantum sensor having a spin defect; excitation means for imparting excitation energy to the spin defect; first electromagnetic wave generating means for generating a resonant electromagnetic wave for a ground level of the spin defect; second electromagnetic wave generating means for generating an electromagnetic wave for an excited level of the spin defect; an electromagnetic wave incident unit for incidenting the resonant electromagnetic wave for the ground level and the electromagnetic wave for the excited level onto the spin defect; photodetection means for detecting an emission intensity of the spin defect when it receives the excitation energy, the resonant electromagnetic wave for the ground level, and the electromagnetic wave for the excited level; and a physical quantity detection unit for detecting a physical quantity based on the emission intensity detected by the photodetection means.

[0008] According to the present invention, it is possible to provide a physical quantity detection device, a physical quantity detection method, and a physical quantity detection program that can improve the detection accuracy of physical quantity detection using a quantum sensor.

[0009] A block diagram showing the configuration of a physical quantity detection device. An explanatory diagram showing the electronic structure in a spin defect. A graph showing the emission intensity when the frequency of a resonant electromagnetic wave for a ground level is changed. A graph showing the emission intensity when the frequency of an electromagnetic wave for an excited level is changed. An explanatory diagram showing an example of a detection condition for a physical quantity. A flowchart showing a physical quantity detection process. A block diagram showing the configuration of a physical quantity detection device in a modified example.

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0011] Fig. 1 is a block diagram showing the configuration of a physical quantity detection device 1. As shown in Fig. 1, the physical quantity detection device 1 includes a quantum sensor 2, an electromagnetic wave incidence unit (electromagnetic wave irradiation unit) 3 that injects (irradiates) a resonant electromagnetic wave into the quantum sensor 2, an excitation unit 4 that imparts excitation energy to the quantum sensor 2, a light detection unit 5 that detects light from the quantum sensor 2, a control unit 6, and an auxiliary storage unit 7.

[0012] The quantum sensor 2 has a defect 2a (hereinafter referred to as a "spin defect") that has electron spin and whose emission intensity changes when the excited level resonates in response to changes in physical quantities such as an electric field, pressure (strain), and temperature. The type of spin defect 2a is not particularly limited as long as it is formed in a solid material (base material) and the emission intensity when the excited level resonates changes depending on the physical quantity. In this embodiment, the spin defect 2a will be described as a silicon vacancy in silicon carbide (SiC-VSi) as an example.

[0013] The quantum sensor 2 having spin defects 2a can be manufactured by implanting ions, irradiating with an electron beam, or irradiating with a neutron beam into a base crystal such as silicon carbide. Alternatively, defects may be introduced intentionally or unintentionally during the growth of the base crystal. Depending on the type of spin defects 2a, a method of performing an appropriate heat treatment can also be used. Furthermore, heat treatment (high-temperature treatment) at an appropriate temperature may be performed to improve the optical properties of the spin defects 2a.

[0014] The electromagnetic wave incidence unit 3 functions as an electromagnetic wave incidence means (electromagnetic wave transmission means) for injecting (transmitting) a resonant electromagnetic wave for the ground level of the spin defect 2 a and an electromagnetic wave for the excited level of the spin defect 2 a into (transmitting) the spin defect 2 a. The electromagnetic wave incidence unit 3 has a first signal generation unit 31, a second signal generation unit 32, a combiner 33, an amplifier 34, and an antenna 35.

[0015] The first signal generating unit 31 generates a signal for generating a ground level resonant electromagnetic wave (a ground level signal). The second signal generating unit 32 generates a signal for generating an excited level electromagnetic wave (an excited level signal). The combiner 33 combines the ground level signal and the excited level signal. The amplifier 34 amplifies the ground level signal and the excited level signal combined by the combiner 33 to a required signal strength. The antenna 35 irradiates the ground level resonant electromagnetic wave toward the spin defect 2a in accordance with the ground level signal amplified by the amplifier 34, and irradiates the excited level electromagnetic wave toward the spin defect 2a in accordance with the excited level signal amplified by the amplifier 34. The antenna 35 is a rod-shaped or wire-shaped metal member, and is preferably provided so that the tip of the antenna 35 is near or in contact with the quantum sensor 2, but is not limited thereto.

[0016] The excitation unit 4 functions as an excitation energy imparting means for imparting excitation energy to the quantum sensor 2 (spin defect 2a) and excites the spin defect 2a. Methods for imparting excitation energy to the spin defect 2a include irradiating excitation light. In this case, the excitation unit 4 has an excitation light source (such as a laser diode (LD) or a light-emitting diode (LED)) for irradiating the excitation light. The wavelength of the excitation light can be set to an optimum value (wavelength) for the spin defect to be used. The excitation unit 4 functions as an excitation light irradiating unit and irradiates the spin defect 2a with excitation light. For example, excitation light corresponding to the energy difference between the ground level and excitation level of the spin defect 2a can be irradiated onto the spin defect 2a to excite electrons in the spin defect 2a. Note that known methods other than the method using excitation light can also be used to impart excitation energy to the spin defect 2a.

[0017] The photodetector 5 receives light from the quantum sensor 2 (spin defects 2a) and outputs an output signal corresponding to the intensity of the incident (irradiated) light (the emission intensity of the spin defects 2a) to the control unit 6. The specific configuration of the photodetector 5 is not particularly limited, and a photodiode or the like can be used. The photodetector 5 is preferably capable of detecting weak light at a low bias, and the material, composition, configuration, etc. are selected according to the wavelength of the emission from the spin defects 2a. Alternatively, an avalanche photodiode (APD) with high light receiving sensitivity and S / N ratio may be used as the photodetector 5.

[0018] The control unit (computer) 6 has an arithmetic unit (CPU) 61 and a main storage unit (memory) 62 that stores various data. This control unit 6 executes at least a temperature detection process. That is, the control unit 6 functions as a temperature detection unit that detects (measures) a temperature based on a signal output from the light detection unit 5. Note that the control unit 6 may also function as a main control unit of the physical quantity detection device 1. In this case, the control unit 6 transmits control signals to each component of the physical quantity detection device 1, such as the excitation unit 4, and causes the physical quantity detection device 1 to perform various operations.

[0019] The auxiliary memory unit 7 is composed of other non-volatile memories such as an HDD, SSD, flash memory, and EEPROM, and stores programs and various data used by the control unit 6 (calculation unit 61) to control the operation of the physical quantity detection device 1.

[0020] The auxiliary memory unit 7 stores at least a main processing program 71 for executing various operations of the physical quantity detection device 1, an excitation program 72 for controlling the excitation unit 4 to impart excitation energy to the spin defect 2a, a first signal generation program 73 for controlling the first signal generation unit 31 to generate a signal for the ground level, a second signal generation program 74 for controlling the second signal generation unit 32 to generate a signal for the excited level, and a physical quantity detection program 75 for detecting a physical quantity in accordance with emission intensity data 76 based on the emission intensity input from the light detection unit 5.

[0021] The auxiliary storage unit 7 also stores at least emission intensity data 76 indicating an output value obtained by converting an output signal input from the light detection unit 5, detection data 77 which is data such as detection conditions for identifying (estimating) a physical quantity from the emission intensity data 76 (output value), and data 78 of the physical quantity detected according to the physical quantity detection program 75. The detection data 77 includes mathematical formula data for calculating the physical quantity from the emission intensity data 76 (output value), table data (calibration table data) for converting the emission intensity data 76 into a physical quantity, etc.

[0022] In the quantum sensor 2 configured as described above, the transition between states that the electrons in the spin defect 2 a can take can be controlled externally. When excitation energy is applied to the electrons in the spin defect 2 a, they are excited via quantum levels (ground level, excited level) formed between the valence band and conduction band of the base material of the quantum sensor 2.

[0023] In this embodiment, the physical quantity to be detected is temperature, and temperature detection is performed using optically detected magnetic resonance (ODMR). The following describes an example in which temperature detection is performed using optically detected magnetic resonance in the physical quantity detection device 1.

[0024] The excitation energy is imparted under irradiation with a ground-level resonant electromagnetic wave and an excited-level electromagnetic wave to manipulate the state of electron spin. Figure 2 is an explanatory diagram showing the electronic structure of a spin defect 2a (a silicon vacancy in silicon carbide (SiC-VSi)). The ground-level resonant electromagnetic wave is an electromagnetic wave for resonating electrons in the ground level, and the excited-level electromagnetic wave is an electromagnetic wave for resonating electrons in the excited level.

[0025] As shown in Figure 2, when the spin defect 2a is irradiated with the ground level resonant electromagnetic wave when the electron is in the ground state (ground level), the electron enters a state (resonant state) in which it is resonated at the ground level (i). When excitation energy is provided to the electron when it is in the ground level, the electron is excited and enters an excited state (excited level) (ii). From this excited state (ii), after remaining for a predetermined period, the electron returns to the ground state with a certain probability, emitting light (a). If no light is emitted, the electron returns to the ground state via a non-emitting level (b). Note that when the electron is in a resonant state due to the ground level resonant electromagnetic wave before excitation energy is provided, the probability of emitting light is higher (the luminescence intensity of the spin defect 2a is higher) than when the electron is not in a resonant state due to the ground level resonant electromagnetic wave.

[0026] In this process, in the present invention, electromagnetic waves for excitation levels are also irradiated (simultaneously). When the electromagnetic waves for excitation levels are irradiated onto the spin defects 2a of electrons in the excited level, the electrons enter a resonant state at the excited level (iii). When electrons enter a resonant state in the excited state, the probability of returning to the ground state without emitting light increases. In other words, irradiation of the electromagnetic waves for excitation levels reduces the probability of emitting light, and ultimately reduces the emission intensity. However, the phenomenon (iii) in which the electromagnetic waves for excitation levels are irradiated onto the spin defects 2a and the electrons enter a resonant state does not occur if the electromagnetic waves for excitation levels are off the resonant frequency (the frequency at which the electrons resonate).

[0027] Fig. 3 is a graph showing the emission intensity of the spin defect 2a when the frequency of the electromagnetic wave for the excitation level is fixed and the frequency of the resonant electromagnetic wave for the ground level is changed. Specifically, Fig. 3 is a graph showing the emission intensity obtained by a test in which the resonant frequency of the excitation level at a certain temperature (test temperature) is examined, the electromagnetic wave for the excitation level is fixed to the resonant frequency of the excitation level at the test temperature, and the frequency of the resonant electromagnetic wave for the ground level is changed in 1 MHz increments (frequency sweep) in a frequency band from 30 MHz to 110 MHz. The test shown in Fig. 3 was performed three times with different intensities of the electromagnetic wave for the excitation level. Specifically, the intensity of the electromagnetic wave for the excitation level was increased in the order of the first test, the second test, and the third test. In Fig. 3, the emission intensity (output value) of the spin defect 2a in the first test is indicated as the emission intensity of the first test G1, the output value in the second test is indicated as the emission intensity of the second test G2, and the emission intensity in the third test is indicated as the emission intensity of the third test G3.

[0028] 3, the emission intensity G1 of the first test, the emission intensity G2 of the second test, and the emission intensity G3 of the third test all have high output values ​​indicating the emission intensity of the spin defects 2a when the frequency of the ground level resonant electromagnetic wave is around 70 MHz (67 MHz to 73 MHz). This is because the ground level resonant frequency of silicon carbide silicon vacancies (SiC-VSi), which are the spin defects 2a of this embodiment, is 70 MHz. The ground level resonant frequency of this SiC-VSi has low temperature dependence, so it remains at 70 MHz even when the temperature changes.

[0029] Furthermore, the emission intensity G2 in the second test is lower than the emission intensity G1 in the first test, and the emission intensity G3 in the third test is lower than the emission intensity G2 in the second test. That is, the emission intensity decreases as the intensity of the electromagnetic wave for excitation levels increases. This is because the phenomenon in which electrons enter a resonant state in the excited state ((iii) in FIG. 2 ) occurs more frequently when the intensity of the electromagnetic wave for excitation levels is higher. This is particularly noticeable near the 70 MHz (67 MHz to 73 MHz) resonance frequency of the ground level. Furthermore, although the emission intensity G3 in the third test near the resonance frequency of the ground level is reduced to about ½ to ⅔ of the emission intensity G1 in the first test, even the emission intensity G3 in the third test is about an order of magnitude larger than the emission intensity change observed when only the electromagnetic wave for excitation levels is irradiated, which is the conventional temperature measurement method. Therefore, the present invention can obtain a larger emission intensity change and improve sensitivity. The frequency of the ground level resonant electromagnetic wave can be set within a range of 67 MHz to 73 MHz, at which the amount of change in emission intensity due to the influence of the excited level electromagnetic wave is maximized, and is preferably fixed at 70 MHz. Furthermore, for the spin defects 2a of this embodiment, a higher emission intensity can be obtained by fixing the frequency of the ground level resonant electromagnetic wave within a range of 67 MHz to 73 MHz, or 70 MHz in this embodiment. When using a material other than SiC-VSi as the spin defects 2a, the frequency of the ground level resonant electromagnetic wave can be swept to determine the frequency of the ground level resonant electromagnetic wave in advance.

[0030] Fig. 4 is a graph showing the emission intensity of the spin defect 2a when the frequency of the ground level resonant electromagnetic wave is fixed and the frequency of the excited level electromagnetic wave is changed within a predetermined frequency band. Specifically, Fig. 4 is a graph showing the emission intensity obtained by a test in which the frequency of the ground level resonant electromagnetic wave is fixed at the ground level resonant frequency (70 MHz) and the excited level electromagnetic wave is changed (frequency swept) in 5 MHz increments within a frequency band of 300 MHz to 500 MHz. The test shown in Fig. 4 was performed twice, changing the intensity of the excited level electromagnetic wave. Specifically, the intensity of the excited level electromagnetic wave increased in the order of the first test and the second test. In Fig. 4, the emission intensity (output value) of the spin defect 2a in the first test is indicated as the emission intensity T1 of the first test, and the output value in the second test is indicated as the emission intensity T2 of the second test.

[0031] 4, both the emission intensity T1 in the first test and the emission intensity T2 in the second test change significantly (the emission intensity decreases significantly) when the frequency of the electromagnetic wave for the excitation level is around 410 MHz. This is because when the frequency of the electromagnetic wave for the excitation level matches the resonance frequency of the excitation level, a phenomenon occurs in which electrons enter a resonance state in the excited state.

[0032] In this way, the frequency of the electromagnetic wave for excitation levels is swept, and the emission intensity change point (emission intensity change frequency) where the emission intensity changes significantly (where a peak of the emission intensity change appears) corresponds to the resonance frequency of the excitation level. For example, within the range of the sweep frequency band, the initial frequency of the electromagnetic wave for excitation levels is sequentially changed by a predetermined frequency (e.g., any frequency between 1 MHz and 10 MHz) to perform the sweep, and the emission intensity of the spin defect 2a is detected for each frequency of the electromagnetic wave for excitation levels changed. The resonance frequency of the excitation level of SiC-VSi is highly temperature-dependent and changes with temperature. That is, the emission intensity change frequency in the emission intensity spectrum obtained by changing the frequency of the electromagnetic wave for excitation levels changes with temperature. Note that the frequency band (sweep frequency band) over which the frequency of the electromagnetic wave for excitation levels is changed includes at least the excitation resonance frequency that resonates at the excitation level and is appropriately set according to the physical quantity to be detected. That is, the sweep frequency band is a frequency band that includes a range from frequencies lower than the excitation resonance frequency to frequencies higher than the excitation resonance frequency. The initial frequency of the electromagnetic wave for the excited level is set within the range of the sweep frequency band.

[0033] The physical quantity detecting device 1 configured as described above performs a temperature detection process to detect temperature based on the emission intensity of the spin defects 2 a obtained by imparting excitation energy to the spin defects 2 a under irradiation with the resonant electromagnetic wave for the ground level and the electromagnetic wave for the excited level. In this temperature detection process, the frequency of the resonant electromagnetic wave for the ground level is fixed to the resonant frequency of the ground level, and the frequency of the electromagnetic wave for the excited level is swept within a predetermined frequency band.

[0034] In addition, when performing the temperature detection process, the frequency of the ground level resonant electromagnetic wave is set depending on the type of spin defect 2a, and detection data 77 indicating the temperature detection conditions based on the relationship between temperature and emission intensity change frequency is created in advance.

[0035] 5 is an explanatory diagram showing an example of temperature detection conditions for SiC-VSi, which is the spin defect 2a of this embodiment. As described above, the resonant frequency of the ground level of SiC-VSi has low temperature dependence, while the resonant frequency of the excited level of SiC-VSi has high temperature dependence. Taking advantage of these characteristics, FIG. 5 shows a correlation table between the emission intensity change frequency and temperature when the frequency of the ground level resonant electromagnetic wave is fixed to the ground level resonant frequency (70 MHz) of SiC-VSi and the excited level electromagnetic wave is swept in the frequency band from 400 MHz to 1060 MHz (quoted from AN Anisimov et al. Scientific Reports 6 33301 (2016)).

[0036] The emission intensity change frequency is detected by the temperature detection process described above, and the temperature corresponding to the emission intensity change frequency can be detected from the correlation table shown in Figure 5. Furthermore, from the correlation table of Figure 5 and the test results for Figure 5, the absolute temperature (K) can be calculated using the following formula [Equation 1]: [Equation 1] K = (1060 - RF) / 2.1 Furthermore, the Celsius temperature (°C) can be calculated using the following formula [Equation 2]: [Equation 2] °C = (1060 - RF) / 2.1 - 273.15

[0037] Here, RF in [Equation 1] and [Equation 2] is the emission intensity change frequency (MHz). Note that the correlation table in Fig. 5 does not include test results at temperatures above 320 K, but it is believed that the correlation between emission intensity change frequency and temperature will continue to follow the trend expressed by [Equation 1] above.

[0038] 6 is a flowchart showing the physical quantity detection process executed by the control unit 6. When the control unit 6 starts the physical quantity detection process, it first sets a sweep frequency band (step S1). Here, the sweep frequency band is set according to the environment in which the temperature detection process is performed using the physical quantity detection device 1. For example, if the physical quantity to be detected is temperature and the temperature detection process is performed in an environment around room temperature, the sweep frequency band is set to a frequency band including 400 MHz (e.g., a frequency band ranging from 300 MHz to 500 MHz). Furthermore, since the emission intensity change frequency and temperature are inversely proportional, the sweep frequency band can be set lower in a high-temperature environment than at room temperature, and higher in a low-temperature environment than at room temperature.

[0039] Next, the initial frequency of the electromagnetic wave for the excited level is set (step S2). The initial frequency of the electromagnetic wave for the excited level is set within the range of the sweep frequency band. Next, the excitation unit 4 is controlled to provide excitation energy to the quantum sensor 2 (spin defect 2a) (step S3), the resonant electromagnetic wave for the ground level is incident on the quantum sensor 2 (spin defect 2a) (step S4), the electromagnetic wave for the excited level is incident on the quantum sensor 2 (spin defect 2a) (step S5), and the emission intensity is detected (emission intensity data is acquired) (step S6).

[0040] When the emission intensity is detected in step S6, it is determined whether or not the sweep is to be terminated (step S7). Here, it is determined whether or not the emission intensity has been detected for the required frequencies of the electromagnetic wave for excitation levels within the sweep frequency band. For example, if it is planned to sequentially change the initial frequency of the electromagnetic wave for excitation levels within the sweep frequency band by, for example, 1 MHz and detect the emission intensity for each frequency of the electromagnetic wave for excitation levels, it is determined whether or not the emission intensity has been detected for all the planned frequencies.

[0041] If it is determined not to end the sweep (step S7: NO), the frequency of the electromagnetic wave for the excitation level is changed (step S8), and the process returns to step S3. That is, if it is determined not to end the sweep (step S7: NO), the processes of steps S3 to S8 are repeated. In step S8, the frequency of the electromagnetic wave for the excitation level is set to a frequency at which the emission intensity has not yet been detected. On the other hand, if it is determined to end the sweep (step S7: YES), the emission intensity data 76 (emission spectrum in the sweep frequency band) detected up to that point is acquired (step S9), the emission intensity change frequency is detected (step S10), and the physical quantity is detected according to the emission intensity change frequency in accordance with the physical quantity detection condition (step S11), and the physical quantity detection process is terminated.

[0042] With the above configuration and operation, in this embodiment, the excitation energy is imparted under irradiation of the ground level resonant electromagnetic wave and the excited level electromagnetic wave, so that irradiation of the ground level resonant electromagnetic wave can obtain a larger change in emission intensity than when only the conventional excited level electromagnetic wave is irradiated, thereby improving the detection accuracy of physical quantity detection using the quantum sensor 2. Furthermore, by obtaining highly sensitive data, it is possible to detect physical quantities with a smaller number of data sets (reducing the number of tests), and shorten the detection time (measurement time). For example, the physical quantity detection device 1 can detect the temperature of the space in which the quantum sensor 2 is placed and the temperature of an object (such as an electronic device) that abuts (contacts) the quantum sensor 2.

[0043] Furthermore, in the above-described embodiment, a sweep frequency band including the excitation resonance frequency is set, and the frequency of the electromagnetic wave for the excitation level, which has a high temperature dependency, is changed in the sweep frequency band to detect the emission intensity change frequency, so that the characteristics of SiC-VSi can be effectively utilized to efficiently detect physical quantities.

[0044] Furthermore, in the above-described embodiment, the combiner 33 combines the signal for the ground level and the signal for the excited level, and the electromagnetic wave incident unit 3 irradiates both the resonant electromagnetic wave for the ground level and the electromagnetic wave for the excited level, so that the amplifier 34 and the antenna 35 can be used in common (combined) for the resonant electromagnetic wave for the ground level and the electromagnetic wave for the excited level. Therefore, the number of parts can be reduced, and the configuration of the physical quantity detection device 1 can be simplified.

[0045] The quantum sensor of this invention corresponds to the quantum sensor 2 of the above embodiment, and similarly hereinafter, the excitation means corresponds to the excitation unit 4, the first electromagnetic wave generating means corresponds to the first signal generating unit 31, the second electromagnetic wave generating means corresponds to the second signal generating unit 32, the electromagnetic wave incident unit corresponds to the antenna 35, the light detecting means corresponds to the light detecting unit 5, the physical quantity detecting unit corresponds to the physical quantity detection program and the control unit 6 that operates in accordance with the program, and the composite electromagnetic wave generating means corresponds to the combiner 33, but this invention is not limited to this embodiment and can be embodied in various other ways. Furthermore, the specific configurations etc. given in the above embodiment are merely examples and can be changed as appropriate depending on the actual product.

[0046] For example, in the above-described embodiment, the electromagnetic wave incident unit 3 includes the amplifier 34, but the amplifier 34 can be omitted. In this way, the number of parts can be reduced and the configuration of the physical quantity detection device 1 can be simplified.

[0047] Furthermore, one or more of the electromagnetic wave incident unit 3, the excitation unit 4, and the light detection unit 5 included in the physical quantity detection device 1 may be provided separately from the physical quantity detection device 1 to configure a physical quantity detection system. Even in this case, the same effects as those of the above-described embodiment can be obtained.

[0048] Furthermore, in the above-described embodiment, the electromagnetic wave incident unit 3 is configured to irradiate both a ground level resonant electromagnetic wave and an excited level electromagnetic wave, but this is not necessarily limited to this. For example, as shown in FIG. 7 , the electromagnetic wave incident unit 3 may have a ground level electromagnetic wave incident unit 3A that emits a ground level resonant electromagnetic wave and an excited level electromagnetic wave incident unit 3B that emits an excited level electromagnetic wave, which are provided independently of each other. In this case, the ground level electromagnetic wave incident unit 3A includes a first signal generating unit 31, a first amplifier 34A, and a first antenna 35A (first electromagnetic wave incident unit). The excited level electromagnetic wave incident unit 3B includes a second signal generating unit 32, a second amplifier 34B, and a second antenna 35B (second electromagnetic wave incident unit). The first amplifier 34A and the second amplifier 34B have the same configuration as the amplifier 34 described above. Furthermore, the first antenna 35A and the second antenna 35B have the same configuration as the antenna 35 described above. With this configuration, it is possible to omit the combiner 33 and obtain the same effects as in the above-described embodiment. Note that, for the sake of convenience, the excitation unit 4, the photodetection unit 5, the control unit 6, and the auxiliary storage unit 7 are not shown in Fig. 7, but the configuration other than the electromagnetic wave incidence unit 3 is the same as in the above-described embodiment.

[0049] Furthermore, a modulation unit may be provided to modulate the amplitude or frequency of at least one of the ground level resonant electromagnetic wave and the excited level electromagnetic wave. For example, the modulation unit may use a signal modulation function added to the signal generating unit that outputs each electromagnetic wave, or an external modulation mechanism. On the detection side, a lock-in amplifier may be provided between the light detection unit 5 and the control unit 6, or an equivalent detection mechanism may be employed. In this case, the emission intensity data may be obtained by modulating either or both of the ground level resonant electromagnetic wave and the excited level electromagnetic wave. The modulation method is preferably, but not limited to, amplitude modulation (AM) or frequency modulation (FM). This method removes noise contained in the emission intensity data 76 and efficiently detects the emission intensity change frequency of the object to be measured.

[0050] In the above-described embodiment, the physical quantity to be measured in SiC-VSi was described as temperature. However, when detecting an electric field or pressure (strain) using a quantum sensor using other spin defects, the physical quantity can be detected in a similar manner by appropriately setting the detection conditions, as long as the physical quantity is measured using an excitation level. Furthermore, the present invention can be provided not only as a physical quantity detection device, but also as a method for detecting a physical quantity using a physical quantity detection device, a program, and a non-transient (non-transient) tangible storage medium storing the program. Furthermore, the number of excitation level electromagnetic waves that the second signal generating unit 32 (second electromagnetic wave generating means) can simultaneously generate can be one or more, and is not particularly limited. When the second signal generating unit 32 simultaneously generates multiple excitation level electromagnetic waves, the frequencies of the multiple excitation level electromagnetic waves can be different from each other.

[0051] The present invention can be used in industries that use quantum sensors to detect physical quantities.

[0052] DESCRIPTION OF SYMBOLS 1 Physical quantity detection device 2 Quantum sensor 2a Spin defect 3 Electromagnetic wave incidence section 31 First signal generation section 32 Second signal generation section 33 Combiner 34 Amplifier 35 Antenna 4 Excitation section 5 Light detection section 6 Control section

Claims

1. a quantum sensor having a spin defect; an excitation means for imparting excitation energy to the spin defect; a first electromagnetic wave generating means for generating a resonant electromagnetic wave for the ground level of the spin defect; a second electromagnetic wave generating means for generating an electromagnetic wave for an excited level of the spin defect; an electromagnetic wave incidence unit that causes the ground level resonant electromagnetic wave and the excited level electromagnetic wave to be incident on the spin defects; a light detection means for detecting the emission intensity of the spin defects when receiving the excitation energy, the ground level resonant electromagnetic wave, and the excited level electromagnetic wave; a physical quantity detection unit that detects a physical quantity based on the light emission intensity detected by the light detection means; Physical quantity detection device.

2. The second electromagnetic wave generating means changes the frequency of the electromagnetic wave for the excitation level in a frequency band including a range from a frequency lower than an excitation resonance frequency at which the excitation level of the spin defect resonates to a frequency higher than the excitation resonance frequency. The physical quantity detection device according to claim 1 .

3. The physical quantity detection unit acquires the emission intensity for each individual frequency of the changed electromagnetic wave for the excitation level, and detects the physical quantity according to an emission intensity change frequency at which a peak of the change in the emission intensity appears. The physical quantity detection device according to claim 2 .

4. a combined electromagnetic wave generating means for generating a combined electromagnetic wave by combining the ground level resonant electromagnetic wave and the excited level electromagnetic wave, The electromagnetic wave incident unit incidents the composite electromagnetic wave onto the spin defect.

4. The physical quantity detection device according to claim 1, 2 or 3.

5. The electromagnetic wave incidence unit includes a first electromagnetic wave incidence unit that causes the ground level resonant electromagnetic wave to be incident on the spin defect, and a second electromagnetic wave incidence unit that causes the excited level electromagnetic wave to be incident on the spin defect.

4. The physical quantity detection device according to claim 1, 2 or 3.

6. The device further includes a modulation means for modulating the amplitude or frequency of at least one of the ground level resonant electromagnetic wave and the excited level electromagnetic wave.

4. The physical quantity detection device according to claim 1, 2 or 3.

7. The present invention further comprises a modulation means for modulating the amplitude or frequency of at least one of the ground level resonant electromagnetic wave and the excited level electromagnetic wave. The physical quantity detection device according to claim 4.

8. The present invention further comprises a modulation means for modulating the amplitude or frequency of at least one of the ground level resonant electromagnetic wave and the excited level electromagnetic wave. The physical quantity detection device according to claim 5 .

9. a physical quantity detection device including a quantum sensor having a spin defect, an excitation means for providing excitation energy to the spin defect, a first electromagnetic wave generating means for generating a resonant electromagnetic wave for the ground level of the spin defect, a second electromagnetic wave generating means for generating an electromagnetic wave for the excited level of the spin defect, an electromagnetic wave incident unit for incidenting the resonant electromagnetic wave for the ground level and the electromagnetic wave for the excited level onto the spin defect, and a light detecting means for detecting the emission intensity of the spin defect, detecting, by the light detection means, the emission intensity of the spin defect when receiving the excitation energy, the ground level resonant electromagnetic wave, and the excited level electromagnetic wave; A physical quantity is detected based on the detected light emission intensity. Physical quantity detection method.

10. A computer-readable program for controlling a physical quantity detection device including a quantum sensor having a spin defect, an excitation means for providing excitation energy to the spin defect, a first electromagnetic wave generating means for generating a resonant electromagnetic wave for a ground level of the spin defect, a second electromagnetic wave generating means for generating an electromagnetic wave for an excited level of the spin defect, and an electromagnetic wave incident unit for incidenting the resonant electromagnetic wave for the ground level and the electromagnetic wave for the excited level onto the spin defect, The computer a light detection means for detecting the emission intensity of the spin defects when receiving the excitation energy, the ground level resonant electromagnetic wave, and the excited level electromagnetic wave; a physical quantity detection program that causes the light detection means to function as a physical quantity detection unit that detects a physical quantity based on the emission intensity detected by the light detection means;