Quantum sensor system

Abstract

This quantum sensor system comprises: a magnetic sensor module disposed spaced apart from a magnetic device to measure a magnetic field from the magnetic device and having a second temperature sensor; and a main circuit operably coupled to the magnetic sensor module and having a first temperature sensor. The main circuit is configured to measure the magnetic field in a specific frequency band on the basis of the temperature value difference between a first temperature value measured by the first temperature sensor and a second temperature value measured by the second temperature sensor.

Description

Quantum sensor system

[0001] The present invention relates to a quantum sensor system. More specifically, it relates to a quantum sensor system for measuring a magnetic field.

[0002] Diamond crystals, composed of carbon atoms, develop lattice defects when carbon atoms are replaced by other types of atoms. These defects are called nitrogen-vacancy centers, where one carbon atom is replaced by a nitrogen atom, leaving a vacant space behind.

[0003] The nitrogen-vacancy (NV) diamond structure has an electron spin with a spin number (S) of 1, and the spin quantum can have three spin states (ms): +1, 0, and -1. In the absence of an external magnetic field along the axis of the nitrogen vacancy in the diamond, the spin quantum of the +1 and -1 spin states (ms) overlap and exist at similar energy levels.

[0004] When a 532 nm wavelength light source is irradiated on the NV diamond structure, the quantum in the spin state (ms=0) is excited and then returns to the ground state while emitting light of 600 nm or more. The quantum in the spin state (ms=+1) and spin state (ms=-1) is excited and then returns to the ground state while changing to the spin state (ms=0).

[0005] When an external magnetic field is applied along the axis of the nitrogen vacancy in the NV diamond structure, the Zeeman effect causes the spin quantum superposition of the +1 and -1 spin states (ms) of the nitrogen vacancy to disappear, and they exist at different energy levels. Accordingly, the nitrogen vacancy spin quantum has two resonant frequencies corresponding to the spin transition between the spin state (ms = 0) and the spin state (ms = +1) or between the spin state (ms = 0) and the spin state (ms = -1). The difference between the two resonant frequencies is proportional to the magnitude of the external magnetic field.

[0006] Meanwhile, quantum sensor systems featuring NV diamond structures may experience errors in magnetic field measurements due to changes in the surrounding temperature of the NV diamond structure. Specifically, when a light source of a specific wavelength is irradiated onto the NV diamond structure, the surrounding temperature of the NV diamond structure may rise, potentially causing errors in magnetic field measurements.

[0007] The purpose of this specification is to provide a quantum sensor system for measuring a magnetic field through an NV diamond structure.

[0008] This is to solve the problem of errors in magnetic field measurement due to changes in the ambient temperature of the NV diamond structure of this specification.

[0009] The purpose of this specification is to solve the problem that an error occurs in magnetic field measurement due to an increase in the ambient temperature of an NV diamond structure when a light source of a specific wavelength is irradiated on the NV diamond structure.

[0010] A quantum sensor system according to the present disclosure comprises: a magnetic sensor module disposed spaced apart from a magnetic device to measure a magnetic field from the magnetic device and having a second temperature sensor; and a main circuit operably coupled to the magnetic sensor module and having a first temperature sensor. The main circuit is configured to measure the magnetic field in a specific frequency band based on a temperature value difference between a first temperature value measured by the first temperature sensor and a second temperature value measured by the second temperature sensor.

[0011] According to an embodiment, the magnetic sensor module may include a first substrate having a light source arranged thereon; and a second substrate arranged vertically apart from the first substrate and having an NV diamond structure and the first temperature sensor arranged thereon. A photodetector arranged vertically apart from the second substrate and configured to detect a signal emitted from the NV diamond structure may be provided in the magnetic sensor module or the main circuit.

[0012] According to an embodiment, the quantum sensor system may further include a lock-in amplifier configured to amplify a signal from the photodetector and output an output signal. The main circuit may be configured to measure the magnetic field according to a slope of the output signal according to a frequency change in a first frequency band when the difference in the temperature values ​​is less than a threshold temperature difference.

[0013] According to an embodiment, the main circuit may be configured to measure the magnetic field according to the slope of the output signal according to the frequency change in a second frequency band when the difference in the temperature values ​​is greater than or equal to the threshold temperature difference. The second frequency band is characterized in that it is a lower frequency band than the first frequency band.

[0014] According to an embodiment, the main circuit may be configured to measure a magnetic field in the specific frequency band or change the specific frequency band in which the magnetic field is to be measured based on an updated temperature value difference between the updated first temperature value and the updated second temperature value.

[0015] According to an embodiment, the main circuit may be configured to control the magnetic sensor module to measure the magnetic field at a resonant frequency of the magnetic sensor module if the updated temperature value difference is less than the threshold temperature difference.

[0016] According to an embodiment, the main circuit may be configured to control the magnetic sensor module so that a resonant frequency of the magnetic sensor module shifts according to the updated temperature value difference when the updated temperature value difference is greater than or equal to the threshold temperature difference, and to control the magnetic sensor module so that the magnetic field is measured at the shifted resonant frequency.

[0017] In an embodiment, the magnetic sensor module may further include a resonator formed on the first substrate on which the light source is disposed and configured to radiate an RF signal. In an embodiment, the magnetic sensor module may further include an RF generator that generates the RF signal and applies it to the resonator. The main circuit may be configured to control the RF generator to generate the RF signal at the shifted resonant frequency.

[0018] According to an embodiment, the main circuit may calculate a frequency shift value according to the difference in the updated temperature value, and calculate a value obtained by dividing the calculated frequency shift value by a minimum frequency sweep interval. The main circuit may be configured to control the RF generator to generate the RF signal at the shifted resonant frequency having a frequency shift interval that is an integer multiple of the calculated divided value, and to control an operating frequency band of the lock-in amplifier to measure the magnetic field at the shifted resonant frequency.

[0019] According to an embodiment, if the updated temperature value difference is greater than or equal to the threshold temperature difference, the RF generator may be configured to control the first resonant frequency of the resonator disposed on the first substrate to be changed based on the updated temperature value difference.

[0020] According to an embodiment, the first temperature sensor may be disposed within the processor of the main circuit or within a measurement module that measures temperature. The second temperature sensor may be disposed within the processor within the magnetic sensor module or within a second measurement module that measures temperature. The second temperature sensor may be disposed on one side or the other side of the NV diamond structure.

[0021] According to an embodiment, the NV diamond structure may be arranged in the slot region of the second substrate such that light from the light source emitted through the slot region of the second substrate is incident thereon.

[0022] According to an embodiment, the light source may be an LED light source in the visible light range, a laser light source, an infrared light source, or an ultraviolet light source.

[0023] According to an embodiment, the first temperature sensor can detect a change in the ambient temperature caused by heat generated from the processor of the main circuit. The main circuit can control the magnetic sensor module so that a transition value of the resonant frequency of the NV diamond structure is reduced due to the change in the ambient temperature. As the transition value of the resonant frequency is reduced, the sensitivity of the magnetic field measurement from the magnetic device can be reduced.

[0024] According to an embodiment, the first temperature sensor and the second temperature sensor may be implemented as at least one of a silicon temperature sensor, a thermistor, an RTD, and a thermocouple that utilizes the temperature dependence of the base voltage (Vbe) of a transistor.

[0025] In an embodiment, the main circuit may track a transition of the resonant frequency according to a single quantum spin structure of a single photon of the NV diamond structure in conjunction with the first and second temperature sensors, and may detect a maximum signal magnitude of the resonator when oscillated by the single photon according to the transition of the resonant frequency. The main circuit may adjust the resonant frequency based on the difference in the maximum signal magnitude and the temperature value to minimize a control error of the single photon.

[0026] In an embodiment, the main circuit may track a transition of the resonant frequency according to a multiple quantum spin structure of the multi-photons of the ensemble NV diamond structure within the NV diamond structure in conjunction with the first and second temperature sensors, and may detect a maximum signal magnitude of the resonator when oscillation is caused by the multi-photons according to the transition of the resonant frequency. The main circuit may adjust the resonant frequency based on the difference in the maximum signal magnitude and the temperature value to minimize a control error of the multi-photons.

[0027] According to an embodiment, if the temperature change amount measured by the second temperature sensor disposed on the second substrate adjacent to the NV diamond structure is less than a threshold value, spin control of the diamond structure can be performed at the resonant frequency. If the temperature change amount measured by the second temperature sensor is greater than or equal to the threshold value, spin control of the diamond structure can be performed at a changed frequency that adds a frequency change amount proportional to the temperature change amount at the resonant frequency.

[0028] According to an embodiment, the quantum system may further include an electromagnetic shielding sheet disposed on the substrate of the main circuit to shield power noise. The electromagnetic shielding sheet may be disposed adjacent to the periphery of the photodetector. The electromagnetic shielding sheet is characterized in that it is a ferrite sheet or a sheet having different properties from ferrite.

[0029] In an embodiment, the main circuit may detect a rate of light intensity decrease over time of an optical signal from the light source through a residue fitting algorithm in conjunction with the photodetector. The main circuit may control the initial operation of the light source and the light intensity attenuation phenomenon through a residue analysis algorithm so that the light intensity decrease over time of the optical signal is compensated for.

[0030] According to the present specification, a quantum sensor system that measures a magnetic field through an NV diamond structure can reduce magnetic field measurement errors due to changes in ambient temperature.

[0031] According to the present specification, a magnetic field measurement error due to a change in ambient temperature can be reduced through a first temperature sensor provided in a main circuit and a second temperature sensor positioned adjacent to an NV diamond structure.

[0032] According to the present specification, a magnetic field measurement error due to an increase in the ambient temperature of an NV diamond structure when a light source of a specific wavelength is irradiated can be reduced through a first temperature sensor provided in a main circuit and a second temperature sensor positioned adjacent to an NV diamond structure.

[0033] Figure 1 shows the NV diamond structure and electron spin analysis results used in a quantum sensor system.

[0034] Figure 2 shows the energy band diagram of the NV diamond structure and the luminescence intensity according to spin.

[0035] Figure 3 shows the change in energy diagram and florescence change according to frequency according to the application of a magnetic field.

[0036] FIGS. 4 and 5 show graphs showing changes in the resonant frequency of an NV diamond structure depending on temperature in a quantum sensor system according to the present specification.

[0037] Fig. 6 shows the configuration of a quantum sensor system according to the present specification.

[0038] Fig. 7 shows a magnetic sensor module formed with a shielding structure for shielding power switching noise according to the present specification.

[0039] Fig. 8 illustrates the configuration of a quantum system including a plurality of components according to the first embodiment. Fig. 9 illustrates the configuration of a quantum system including a plurality of components according to the second embodiment.

[0040] Figure 9 illustrates the configuration of a quantum system including a plurality of components according to the second embodiment.

[0041] Figure 10 shows the output voltage according to the change in frequency of the NV diamond structure.

[0042] Figure 11 shows the output voltages according to the frequency transition under the first and second temperature conditions of graph 1 (Gr1) and graph 2 (Gr2).

[0043] FIG. 12 shows a flowchart of a control method of a quantum sensor system that measures a magnetic field in different ways based on an updated temperature value difference between a first temperature value and a second temperature value.

[0044] Figure 13 shows the change in light intensity according to spin state in a quantum sensor system according to the present specification.

[0045] Figure 14 shows a conceptual diagram of a continuous magnetic field measurement method using an interferometer according to the first embodiment.

[0046] Figure 15 shows a conceptual diagram of an oscillation period measurement method according to the second embodiment.

[0047] Figure 16 shows a graph showing the decrease in light intensity over time of an optical signal of a quantum sensor system according to the present specification and a graph showing compensation for the decrease in light intensity.

[0048] The technology disclosed herein is applicable to a quantum sensor system that measures magnetic fields. However, the technology disclosed herein is not limited thereto and can be applied to any quantum sensor system that measures magnetic fields to which the technical principles of the technology can be applied.

[0049] It should be noted that the technical terms used in this specification are used merely to describe specific embodiments and are not intended to limit the present invention. Furthermore, unless specifically defined otherwise herein, the technical terms used herein should be interpreted as having a meaning generally understood by those skilled in the art to which the present invention pertains, and should not be interpreted in an excessively broad or narrow sense. Furthermore, if a technical term used herein is incorrect and does not accurately express the spirit of the present invention, it should be replaced with a technical term that can be correctly understood by those skilled in the art. Furthermore, general terms used herein should be interpreted according to their dictionary definitions or according to the context, and should not be interpreted in an excessively narrow sense.

[0050] Additionally, the singular expressions used herein include plural expressions unless the context clearly dictates otherwise. In this application, terms such as "consist of" or "comprises" should not be construed to necessarily include all of the various components or various steps described in the specification, and should be construed to mean that some of the components or some of the steps may not be included, or that additional components or steps may be included.

[0051] In addition, the suffixes "module" and "part" used in this specification for components are given or used interchangeably only for the convenience of writing the specification, and do not have distinct meanings or roles in themselves.

[0052] Additionally, terms including ordinal numbers, such as "first," "second," etc., used herein may be used to describe various components, but these components should not be limited by these terms. These terms are used solely to distinguish one component from another. For example, without departing from the scope of the present invention, a first component could be referred to as a "second component," and similarly, a second component could also be referred to as a "first component."

[0053] Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the attached drawings. Regardless of the drawing numbers, identical or similar components are given the same reference numbers, and redundant descriptions thereof will be omitted.

[0054] Furthermore, when describing the present invention, detailed descriptions of related known technologies will be omitted if they are deemed to obscure the gist of the present invention. Furthermore, it should be noted that the attached drawings are intended solely to facilitate understanding of the spirit of the present invention and should not be construed as limiting the spirit of the present invention.

[0055] In this regard, Fig. 1 illustrates the NV diamond structure used in a quantum sensor system and the results of electron spin analysis. Fig. 1(a) illustrates the NV diamond structure. Fig. 1(b) shows the wavelengths of the input and output signals incident on the NV diamond structure. Fig. 1(c) shows the change in electron spin of the NV diamond structure according to the ambient magnetic field characteristics or temperature changes.

[0056] Referring to Fig. 1(a), the NV diamond structure (10) can be configured to include nitrogen (N) and a vacancy (V). Quantum qubits can be controlled by utilizing defects in the internal atomic structure of the diamond associated with the NV diamond structure (10). An NV diamond structure (10) having an NV center structure in which one nitrogen atom is arranged between closely packed carbon (C) atoms forming the diamond and a vacancy (V) is formed can be created. Electrons can be used as qubits in the NV diamond structure (10). Quantum computers, quantum communications, quantum sensors, etc. can be implemented using the NV diamond structure (10).

[0057] Other quantum computer technologies, such as superconducting and ion dot-based quantum computers, require ultra-low temperatures or extreme vacuum conditions to manipulate sensitive qubits in a stable environment. In contrast, the diamond NV center method can operate at room temperature thanks to the surrounding solid carbon atoms. This allows for implementation without the massive cooling systems required for superconducting quantum computers.

[0058] Referring to Fig. 1(b), an RF signal having a first frequency (e.g., 2.87 GHz) can be input to the NV diamond structure (10). An optical signal having a first wavelength within a predetermined range based on 532 nm can be input (applied) to the NV diamond structure (10). A second optical signal having a second wavelength greater than the first wavelength can be output from the NV diamond structure (10). In this regard, a second optical signal having a second wavelength within a predetermined range based on 637 nm can be output (emitted) from the NV diamond structure (10). Therefore, a quantum sensor system can be implemented with an optical system configuration for detecting / analyzing an RF signal for generating / controlling a quantum state.

[0059] Referring to Fig. 1(c), the NV center electron spin of the NV diamond structure changes depending on the characteristics of the surrounding magnetic field. The resonant frequencies are separated by the Zeenman splitting phenomenon depending on the characteristics of the surrounding magnetic field. Therefore, the surrounding magnetic field characteristics of the NV diamond structure can be measured by detecting the changes in the resonant frequencies.

[0060] Fig. 2 shows an energy band diagram of an NV diamond structure and luminescence intensity according to spin. Referring to Figs. 1 and 2, when an optical signal of a first wavelength (e.g., 532 nm) is applied to an NV diamond structure (10) in a ground state, the diamond structure (10) can transition to an excited state. Accordingly, the NV diamond structure (10) can undergo an energy band transition from a valence band to a conduction band.

[0061] Meanwhile, the NV diamond structure (10) in this state can transition to the ground state while outputting an optical signal of a second wavelength (e.g., 637 nm). Accordingly, the NV diamond structure (10) can have its energy band transitioned from the conduction band to the valence band. The energy band of the NV diamond structure (10) can be arranged within the conduction band and the valence band.

[0062] If the quantum state of the NV diamond structure (10) converted from the excited state to the ground state is ±1, the luminescence intensity of the NV diamond structure (10) can be formed lower than the threshold at the second wavelength. In this regard, the NV diamond structure (10) can be formed with a higher luminescence intensity in a wavelength band higher than the second wavelength. If the quantum state of the NV diamond structure (10) converted from the excited state to the ground state is 0, the luminescence intensity of the NV diamond structure (10) can be formed higher than the threshold at the second wavelength.

[0063] Figure 3 shows the change in energy diagram and the change in florescence by frequency according to the application of a magnetic field. Figure 3(a) shows the change in energy diagram by the application of a magnetic field. Figure 3(b) shows the change in florescence by frequency according to the application of a magnetic field. Referring to Figure 3(a), when a magnetic field (B) is applied, the spacing between band structures increases due to the Zeenman splitting phenomenon caused by the magnetic field (B). Referring to Figure 3(b), when the magnetic field is 0, a single resonant frequency of 2.87 GHz is formed. On the other hand, when a magnetic field (B) is applied, dual resonance occurs at frequencies lower and higher than 2.87 GHz due to the magnetic field (B). Therefore, the measurement of the surrounding magnetic field is possible by analyzing the changed resonant frequency.

[0064] Hereinafter, a quantum sensor system according to the present specification will be described. FIGS. 4 and 5 illustrate graphs showing changes in the resonant frequency of an NV diamond structure depending on temperature in a quantum sensor system according to the present specification.

[0065] Referring to FIGS. 1 and 4, as the temperature of the region where the NV diamond structure (10) is arranged increases, the resonant frequency shifts to a lower frequency. For example, when the temperature is 295 K, the resonant frequency is formed at 2.87 GHz. On the other hand, when the temperature increases to 325 K, the resonant frequency is formed at 2.86 GHz.

[0066] Referring to FIGS. 1, 4, and 5, as the temperature of the region where the NV diamond structure (10) is arranged increases, the resonant frequency shifts to a lower frequency. Specifically, as the temperature increases, the resonant frequency shifts to a lower frequency at a rate of 74.2 kHz / K.

[0067] The transition of the center frequency of the NV diamond structure (10) has a linear relationship with the change in temperature. When entering the ultra-low temperature range, the linear characteristic is lost as the adjacent spacing between the Nitrogen / Vacancy / Carbon molecules reaches the limit. However, since the greatest advantage of the NV diamond structure (10) is its room-temperature quantum properties, it can be used in the actual room-temperature range.

[0068] Meanwhile, Fig. 6 illustrates the configuration of a quantum sensor system according to the present specification. Referring to Fig. 6, the quantum sensor system (2000) may be configured to include a magnetic sensor module (1100) and a main circuit (1200).

[0069] The magnetic sensor module (1100) may be disposed apart from the magnetic device (1) to measure a magnetic field from the magnetic device (1). The magnetic sensor module (1100) may be implemented as a PCB (Printed Circuit Board). The magnetic device (1) may be a part of the human body that emits a human body magnetic field, in addition to any electronic device that emits a magnetic field. The magnetic field emitted from the magnetic device (1) may be a direct current magnetic field, but is not limited thereto and may also include an alternating current magnetic field. The magnetic sensor module (1100) may be equipped with a second temperature sensor (TS2) to measure a temperature change.

[0070] The main circuit (1200) can be operably coupled with a magnetic sensor module (1100). The main circuit (1200) can be implemented as an MCU (Micro Control Unit) or an AP (Application Processor), but is not limited thereto and can be changed depending on the application. The magnetic sensor module (1100) can be implemented as a substrate such as a PCB, and the main circuit (1200) can be implemented as a substrate on which a processor such as an MCU or an AP is disposed. The substrates of the magnetic sensor module (1100) and the main circuit (1200) can be operably coupled to transmit and receive signals via a cable.

[0071] The main circuit (1200) may be configured to interact with a second temperature sensor (TS2) of the magnetic sensor module (1100). The main circuit (1200) may be configured to include a first temperature sensor (TS1) to measure temperature changes.

[0072] Meanwhile, a quantum sensor system operated at low power must minimize the distance between the light source and the NV diamond structure to minimize optical loss. Accordingly, a quantum sensor system operated at low power may be more vulnerable to heat generated by the light source. To address this issue, a quantum sensor system (2000) according to the present specification may be configured to measure a magnetic field based on the temperature difference between a first temperature sensor (TS1) of a main circuit (1200) and a second temperature sensor (TS2) of a magnetic sensor module (1100).

[0073] In this regard, the main circuit (1200) may be configured to measure a magnetic field in a specific frequency band based on the difference between the temperature values ​​of the first temperature value measured by the first temperature sensor (TS1) and the second temperature value measured by the second temperature sensor (TS2). The main circuit (1200) may measure a magnetic field from the magnetic device (1) in a specific frequency band based on the difference between the temperature values ​​of the first temperature value and the second temperature value.

[0074] The main circuit (1200) can control the resonance frequency of the magnetic sensor module (1100) to be changed based on the threshold value when the transition of the resonance frequency is greater than or equal to a threshold value. The main circuit (1200) can control the resonance frequency of the RF signal of the magnetic sensor module (1100) to be changed based on the transitioned resonance frequency. To this end, the main circuit (1200) can control the resonance frequency of the resonator of the magnetic sensor module (1100) or the oscillation frequency of the oscillator to be changed.

[0075] The magnetic sensor module (1100) may be configured to include a first substrate (100), a second substrate (100b), and a photo detector (420). The photo detector (420) may be configured as a photodiode, but is not limited thereto. The photo detector (420) is not limited to being arranged in the magnetic sensor module (1100). Depending on the application, the photo detector (420) may also be arranged in the main circuit (1200).

[0076] A light source (510) may be placed on a first substrate (100). The light source (510) may be configured to emit a light signal of a first wavelength. The light source (510) may be configured to emit a light signal having a wavelength within a predetermined range based on 532 nm. The light source (510) may be formed as an LED light source in the visible light region, a laser light source, an infrared light source, or an ultraviolet light source.

[0077] The second substrate (100b) may be disposed spaced apart from the first substrate (100) in the direction of a vertical axis (e.g., Z-axis). The second substrate (100b) may be disposed below the first substrate (100) in the direction of the Z-axis, parallel to the first substrate (100). An NV diamond structure (10) and a second temperature sensor (TS2) may be disposed on the second substrate (100b). The second temperature sensor (TS2) may be configured to detect a temperature change due to heat generated from a light source (510). The temperature sensor (TS2) disposed on the second substrate (TS2) may detect a temperature change due to heat generated from a light source (510) disposed on the first substrate (TS1).

[0078] The NV diamond structure (10) can be placed in the slot region (SR) of the second substrate (100b) so that light from a light source (510) emitted through the slot region (SR) of the second substrate (100b) is incident thereon. The slot region (SR) of the second substrate (100b) can also be formed as a dielectric region having a predetermined permittivity or lower so that light from the light source (510) is incident thereon.

[0079] The photo detector (420) may be arranged to be spaced apart from the second substrate (100b) in the direction of a vertical axis (e.g., the Z-axis). The photo detector (420) may be arranged on the first substrate (100) in the Z-axis direction, parallel to the second substrate (100b). The photo detector (420) may be configured to detect a signal emitted from the NV diamond structure (10) arranged on the first substrate (100). The NV diamond structure (10) may be configured to emit a second optical signal having a second wavelength greater than the first wavelength. The NV diamond structure (10) may be configured to emit a second optical signal having a wavelength within a predetermined range based on 637 nm.

[0080] Meanwhile, the quantum sensor system according to the present specification may be formed with a shielding structure for shielding power switching noise, etc. In this regard, Fig. 7 illustrates a magnetic sensor module formed with a shielding structure for shielding power switching noise according to the present specification.

[0081] Referring to FIGS. 6 and 7, the substrate of the main circuit (1200) of the quantum sensor system (2000) can be operably coupled to the substrate (100) of the magnetic sensor module (1100). The substrate of the main circuit (1200) can be coupled to the substrate (100) of the magnetic sensor module (1100) via a connector module (100c).

[0082] The quantum sensor system (2000) may have an electromagnetic shielding sheet (520) placed on the substrate of the main circuit (1300) to shield power noise. The electromagnetic shielding sheet (520) may be placed adjacent to the main circuit (1300) to prevent power noise signals from entering. The electromagnetic shielding sheet (520) may be placed between the main circuit (1300) and the photo detector (420). One side of the electromagnetic shielding sheet (520) may be placed on the substrate of the main circuit (1300). The other side of the electromagnetic shielding sheet (520) may be placed on the photo detector (420).

[0083] The electromagnetic wave shielding sheet (520) may be placed adjacent to the periphery of the photo detector (420). One side of the electromagnetic wave shielding sheet (520) may be placed on the substrate of the main circuit (1300). The side of the electromagnetic wave shielding sheet (520) may be placed adjacent to the periphery of the photo detector (420).

[0084] The electromagnetic wave shielding sheet (520) may be implemented as a ferrite sheet to shield power noise. The electromagnetic wave shielding sheet (520) may be implemented as a sheet with different properties from ferrite to shield power noise. The electromagnetic wave shielding sheet (520) may be placed on the lower portion of the substrate of the main circuit (1300) to eliminate switching noise of the power supply generated in the main circuit (1300).

[0085] A ferrite sheet or a sheet of other material properties can be attached to the lower portion of the substrate of the main circuit (1300) to reduce power noise and improve sensor measurement sensitivity. In this regard, the lock-in measurement standard deviation, such as the change in resonant frequency due to temperature change of the quantum sensor system (2000), can be improved from 0.108 to 0.066.

[0086] Meanwhile, the quantum sensor system according to the present specification may be configured to include a resonator and an RF generator in addition to a light source and a photodetector.

[0087] Fig. 8 illustrates the configuration of a quantum system including a plurality of components according to the first embodiment. Fig. 9 illustrates the configuration of a quantum system including a plurality of components according to the second embodiment.

[0088] Referring to FIG. 8, a quantum sensor system (2000a) may be configured to include an RF generator (20), an NV diamond structure (10), a photodetector (420), a light source (510), filters (310, 320), lenses (331, 332, 333, 334), and a reflective surface (340). The reflective surface (340) may be formed to reflect an optical signal of a first wavelength, such as 532 nm, and to allow an optical signal of a second wavelength, such as 637 nm, to pass therethrough.

[0089] The optical signal received from the photodetector (420) may be amplified through the lock-in amplifier (30). The RF generator (20) may be configured to generate an RF signal of a specific frequency. Based on the signal level amplified through the lock-in amplifier (30), the RF generator (20) may generate an RF signal of a specific signal level of a specific frequency. The RF signal of a specific frequency generated by the RF generator (20) may be transmitted to the resonator (520). The resonator (520) may be configured to radiate an RF signal of a specific frequency band. Accordingly, the resonator (520) radiating an RF signal of a specific frequency band may also be referred to as an antenna (520).

[0090] A 2.87 GHz RF signal radiated from a resonator (520) can be transmitted to an NV diamond structure (10). A GRIN (Gradient Index) lens (335) can be placed between the NV diamond structure (10) and the reflective surface (340). The GRIN lens (335) is manufactured using a polymer material cross method to implement various refractive indices.

[0091] The structure of the quantum sensor system (2000a) becomes complex and bulky due to the inclusion of filters (310, 320), lenses (331, 332, 333, 334), and a reflective surface (340). The quantum sensor system (2000a) may be configured to irradiate an optical signal of a first wavelength emitted from a light source (510) to a focal point of the NV diamond structure (10). To this end, the quantum sensor system (2000a) needs to be provided with filters (310, 320) and lenses (331, 332, 333, 334) so ​​that the optical signal of the first wavelength is irradiated to the focal point of the NV diamond structure (10).

[0092] Meanwhile, whenever the optical signal of the first wavelength passes through the filter (310) and the lenses (331, 332), an attenuation of optical power of about 20% or more occurs. Whenever the optical signal of the second wavelength passes through the filter (320) and the lenses (333, 334), an attenuation of optical power of about 20% or more occurs. Accordingly, the optical power actually irradiated to the focus of the NV diamond structure (10) may be less than 10% of the power emitted from the light source (510). Therefore, sufficient light must be irradiated to the focus of the NV diamond structure (10) to increase the optical power in order to secure ODMR contrast and sensitivity.

[0093] To this end, the light source (510) needs to be implemented as a laser light source. However, the laser light source requires high power, and the photodiode and lens for laser driving and output power feedback take up a large volume. Therefore, the laser light source has limitations in low-power battery operation and miniaturization. In addition, since the laser is used as a light source, it is not easy to integrate it with an antenna (resonator) to excite the NV diamond structure (10), so the quantum sensor system (2000a) having a reflective surface (340) is implemented in a reflective manner.

[0094] Referring to FIGS. 6, 7, and 9, the quantum sensor system (2000) can minimize light attenuation by arranging the NV diamond structure (10) adjacent to the upper region of the light source (510) at a predetermined interval on the Z-axis. In this regard, the NV diamond structure (10) can be arranged above the light source (510) to irradiate light to the center of the NV diamond structure (10) without light attenuation. Therefore, sufficient light can be irradiated to the NV diamond structure (10) even with a low-power light source such as an LED instead of a laser light source. Therefore, the quantum sensor system (2000) can be driven by a low-power battery, and the quantum sensor system (2000) can also be implemented as a wireless communication module.

[0095] Accordingly, as shown in Fig. 8, most of the filters (310, 320), lenses (331, 332, 333, 334) for focusing, and the reflective surface (340) can be removed, thereby enabling miniaturization of the quantum sensor system (2000). In this regard, an RF antenna such as a resonator can be implemented integrally on the substrate (100) to implement the excited state of the NV diamond structure (10) without a separate reflective surface.

[0096] A quantum sensor system (2000) includes a light source (510), an NV diamond structure (10), a photo detector (420), a filter (320), and a lens (333). An RF generator (20) and a lock-in amplifier (30) may be disposed in a main circuit or a magnetic sensor module of the quantum sensor system (2000). The light source (510), an NV diamond structure (10), a photo detector (420), a filter (320), and a lens (333) may be disposed in a magnetic sensor module of the quantum sensor system (2000).

[0097] Miniaturization of the quantum sensor system (2000) is possible by arranging the light source (510), filter (320), and lens (333) on a straight line connecting the center of the NV diamond structure (10) and the center of the photodetector (420). In addition, when using an LED as the light source (510), the sensitivity of 1uT or higher can be improved to 100nT with the modified structure.

[0098] Meanwhile, the quantum sensor system according to the present specification can measure a magnetic field by changing the frequency band according to the difference in temperature value. In this regard, the quantum sensor system according to the present specification can be configured to compensate for the shift of the resonant frequency due to the change in temperature. Fig. 10 shows the output voltage according to the change in frequency of the NV diamond structure. Referring to Fig. 10, (i) Graph 1 (Gr1) compared to (ii) Graph 2 (Gr2) shows the output voltage according to the change in frequency at a higher temperature. Referring to Graph 1 (Gr1) and Graph 2 (Gr2), it can be seen that the resonant frequency of the quantum sensor system shifts (transitions) to a lower frequency as the temperature increases.

[0099] For Graph 1 (Gr1) and Graph 2 (Gr2), the slope of the frequency range transitioned in a specific frequency range can be measured. For example, the slope of the change in output voltage according to the frequency change can be measured in a specific frequency range between frequencies greater than 2.87 GHz and frequencies less than 2.88 GHz.

[0100] In this regard, when measuring minute magnetic field changes, it is not easy to detect changes in the intervals at which the band structure is separated. Therefore, it is necessary to precisely measure the change in the slope of electrical properties according to frequency change using a lock-in amplifier. In order to detect minute changes in the slope of electrical properties according to frequency change, it is necessary to detect changes in the same frequency range. On the other hand, if the frequency of the NV diamond structure shifts due to temperature change, the slope of another shifted frequency range is measured, which may be erroneously measured as a change in the magnetic field.

[0101] Fig. 11 shows output voltages according to frequency transition under the first and second temperature conditions of graph 1 (Gr1) and graph 2 (Gr2). Referring to Figs. 6 to 11, measurement of the slope of change in the output voltage, which is an electrical property according to the frequency transition, will be described. The ambient temperature measured by the first temperature sensor (TS1) arranged in the main circuit (1300) may be 23.9°C, and the temperature measured by the second temperature sensor (TS2) arranged adjacent to the NV diamond structure (10) of the magnetic sensor module (1100) may be 51°C. The temperature difference T = 27K, and the frequency transition value may be 2.0034 MHz, which is the product of the slope value of 0.0742 and the temperature difference T = 27K. Meanwhile, the frequency shift interval through the experiment is 0.2235 MHz, and the shift interval can be set to 9 ≒ 8.9637 = 2.0034 MHz / 0.2235 MHz. Therefore, the slope of the 9-interval shift section needs to be measured for frequency shift compensation.

[0102] Meanwhile, the incorrectly measured slope value before frequency shift compensation is 1644.689, which may be misrecognized as a magnetic field change. Meanwhile, the frequency shift-compensated slope value may be 1789.914. This difference in slope values ​​can improve the accuracy of compensation through additional frequency compensation rather than frequency control at the PCB level.

[0103] Referring to FIGS. 6, 7 to 11, a quantum sensor system (2000) according to the present specification will be described. The quantum sensor system (2000) may further include a lock-in amplifier (30). The lock-in amplifier (30) may be configured to amplify a signal from a photodetector (420) and output an output signal. The main circuit (1200) may measure a magnetic field according to a slope of an output signal according to a frequency change in a first frequency band (BW1) when a difference in temperature values ​​is less than a threshold temperature difference. When the difference in temperature values ​​is less than a threshold temperature difference, the slope of the output signal according to a frequency change in the first frequency band (BW1) has linearity, enabling accurate magnetic field measurement.

[0104] If the difference in temperature values ​​is greater than the critical temperature difference, the slope of the output signal according to the frequency change in the first frequency band (BW1) may be non-linear, which may cause errors in the magnetic field measurement. However, the slope of the output signal according to the frequency change in the second frequency band (BW2) lower than the first frequency band (BW1) is linear, which allows for accurate magnetic field measurement.

[0105] Accordingly, the main circuit (1200) can measure a magnetic field according to the slope of the output signal according to the frequency change in the second frequency band (BW2) if the difference in temperature values ​​is greater than or equal to the critical temperature difference. In this regard, the temperature increase due to a light-emitting source such as a light source (510) or an NV diamond structure (10) is achieved through heat conduction, radiation, and / or convection. Meanwhile, since an additional temperature increase is accompanied by integration between multiple electronic components, frequency change compensation is required for accurate magnetic field measurement.

[0106] Meanwhile, as the temperature rises due to the light source (510), the resonant frequency of the magnetic sensor module (1100) shifts to a lower frequency band. Accordingly, the second frequency band (BW2) for measuring the magnetic field can be set to a lower frequency band than the first frequency band (BW1).

[0107] Meanwhile, the quantum sensor system according to the present specification can measure a magnetic field in different ways based on the updated temperature difference between the first temperature value and the second temperature value. In this regard, FIG. 12 illustrates a flowchart of a control method for a quantum sensor system that measures a magnetic field in different ways based on the updated temperature difference between the first temperature value and the second temperature value.

[0108] The control method of the quantum sensor system can be performed by the main circuit (1100) of Fig. 6. The control method of the quantum sensor system can include a magnetic field measurement preparation process (S10), a first temperature value reception process (S100), a temperature value difference comparison process (S200), a magnetic field measurement process (S300), and a calibration process (S400).

[0109] Referring to FIGS. 6 to 12, in the magnetic field measurement preparation process (S10), the main circuit (1200) obtains first and second temperature values ​​from the first and second temperature sensors (TS1, TS2) and prepares to measure a magnetic field from the magnetic device. In the first temperature value reception process (S100), the main circuit (1200) can receive an updated first temperature value of the magnetic sensor module (1100).

[0110] In the temperature value difference comparison process (S200), the main circuit (1200) determines whether the temperature value difference (ΔT) between the first temperature value and the updated second temperature value is greater than or equal to a threshold value (Thr.). If the temperature value difference (ΔT) is less than the threshold value (Thr.), the magnetic field measurement process (S300) is performed. In the magnetic field measurement process (S300), the main circuit (1200) can control the lock-in amplifier (300) to measure the magnetic field based on the previously measured resonant frequency.

[0111] If the temperature difference (ΔT) between the first temperature value and the updated second temperature value is greater than or equal to a threshold value (Thr.), a calibration process (S400) may be performed. In the calibration process (S400), the main circuit (1200) may adjust the resonant frequency of the RF generator and the resonator by the amount of the resonant frequency that shifts in response to the temperature difference (ΔT). In the magnetic field measurement process (S300), the main circuit (1200) may control the lock-in amplifier (300) to measure the magnetic field based on the adjusted resonant frequency.

[0112] In this regard, the main circuit (1200) can measure the magnetic field in different ways based on the updated temperature value difference between the updated first temperature value and the updated second temperature value. The main circuit (1200) can measure the magnetic field in a specific frequency band or change the specific frequency band in which the magnetic field is to be measured based on the updated temperature value difference.

[0113] Specifically, the main circuit (1200) can control the magnetic sensor to measure a magnetic field at the resonant frequency of the magnetic sensor module (1100) if the updated temperature value difference is less than the threshold temperature difference. For example, the main circuit (1200) can measure the magnetic field according to the slope of the output signal according to the frequency change at the resonant frequency of 2.876 GHz.

[0114] The main circuit (1200) can control the magnetic sensor module (1100) so that the resonant frequency of the magnetic sensor module (1100) shifts according to the critical temperature difference when the updated temperature value difference is greater than or equal to the critical temperature difference. For example, the main circuit (1200) can measure the magnetic field according to the slope of the output signal according to the frequency change at the resonant frequency of 2.873 GHz, which is shifted by 9 intervals from the previous resonant frequency of 2.876 GHz. The main circuit (1200) can control the magnetic sensor module (1100) to measure the magnetic field at the shifted resonant frequency.

[0115] Meanwhile, the quantum sensor system according to the present specification may be configured to measure a magnetic field at a shifted resonant frequency by interfacing with a resonator and an RF generator. In this regard, the magnetic sensor module (1100) may further include a resonator (520) and an RF generator (20).

[0116] A resonator (520) may be formed on a first substrate (100) on which a light source (510) is disposed and configured to radiate an RF signal. The resonator (520) may be configured to radiate an RF signal toward an NV diamond structure (10) disposed on the first substrate (100). An RF generator (20) may generate an RF signal of a specific frequency band and apply the RF signal to the resonator (520). The RF generator (20) may be implemented as a VCO (Voltage Controlled Oscillator) that outputs a signal of a variable frequency that changes according to voltage, but is not limited thereto and may be changed according to the application. The main circuit (1200) may control the RF generator (20) to generate an RF signal at a resonant frequency that changes according to temperature change.

[0117] In this regard, the main circuit (1100) can calculate a frequency shift value according to the updated temperature value difference. The main circuit (1100) can calculate a value obtained by dividing the calculated frequency shift value by a minimum frequency sweep interval. The main circuit (1100) can control the RF generator (20) to generate an RF signal at a shifted resonant frequency having a frequency shift interval that is an integer multiple of the calculated divided value. The main circuit (1100) can control the lock-in amplifier (30) to measure a magnetic field at the shifted resonant frequency according to a temperature change. The main circuit (1100) can control an operating frequency band of the lock-in amplifier (30) to measure a magnetic field at the shifted resonant frequency according to a temperature change.

[0118] In this regard, the lock-in amplifier (30) may be configured to selectively amplify signals in a specific frequency band and filter out signals in the remaining adjacent frequency bands. The lock-in amplifier (30) may be configured to modulate and amplify only signals in a variable frequency band. For example, the lock-in amplifier (30) may modulate, filter, and amplify only signals in a specific frequency band at intervals of 500 kHz or 1 MHz. Accordingly, when the temperature increases due to the light emission of the light source (510), the lock-in amplifier (30) may selectively amplify signals in a frequency band including the shifted resonant frequency so as to measure a magnetic field at the shifted resonant frequency at intervals of 500 kHz or 1 MHz.

[0119] Meanwhile, the quantum sensor system according to the present specification can change the resonant frequency and / or the wavelength of the light source based on the transition of the resonant frequency of the magnetic sensor module (1100) or the difference in the updated temperature value. In this regard, if the updated temperature value difference is greater than or equal to a threshold temperature difference, the magnetic sensor module (1100) can control the wavelength of the light source (510) to be changed based on the updated temperature value difference. If the transition of the resonant frequency of the magnetic sensor module (1100) is greater than or equal to a threshold value, the magnetic sensor module (1100) can control the wavelength of the light source (510) to be changed based on the threshold value.

[0120] Meanwhile, if the updated temperature value difference is greater than or equal to the threshold temperature difference, the magnetic sensor module (1100) can control the first resonant frequency of the resonator (520) disposed on the first substrate (100) to be changed based on the updated temperature value difference. In this regard, the magnetic sensor module (1100) can control the resonant frequency of the RF generator (20) so that the first resonant frequency of the resonator (520) is changed.

[0121] If the transition of the resonance frequency of the magnetic sensor module (1100) is greater than or equal to a threshold value, the magnetic sensor module (1100) can control the first resonance frequency of the resonator (520) arranged on the first substrate (100) to be changed based on the threshold value.

[0122] The first temperature sensor (TS1) can detect changes in the ambient temperature caused by heat generated from the processor of the main circuit (1130). The main circuit (1200) can control the magnetic sensor module (1100) so that the transition value of the resonant frequency of the NV diamond structure (10) is reduced due to changes in the ambient temperature.

[0123] As described above, the temperature value difference is T = 27K, and the resonant frequency can be changed from 2.876 GHz to 2.873 GHz, which is a resonant frequency shifted by 9 intervals, as the temperature increases due to heat generation by the light source (510) or the NV diamond structure (10). Meanwhile, if the temperature value difference between the first and second temperature values ​​decreases as the external temperature increases, the resonant frequency of the resonator (520) can be controlled to increase. Accordingly, the resonant frequency of the resonator (520) can be controlled to increase by a predetermined interval from 2.873 GHz. The resonant frequency of the resonator (520) can be set to a value greater than 2.873 GHz and less than 2.876 GHz.

[0124] Accordingly, even if there is no temperature increase due to heat generation from the light source (510) or the NV diamond structure (10), the influence of changes in the external temperature can be considered. As the transition value of the resonant frequency decreases, the sensitivity of the magnetic field measurement from the magnetic device (1) can decrease. As another example, if the temperature difference between the first and second temperature values ​​increases due to a decrease in the external temperature, the resonant frequency of the resonator (520) can be controlled to decrease.

[0125] As described above, the first temperature sensor (TS1) and the second temperature sensor (TS2) may be positioned in different areas. The first temperature sensor (TS1) may be positioned within the processor of the main circuit (1200) or within a measurement module that measures temperature. The second temperature sensor (TS2) may be positioned within the processor of the magnetic sensor module (1100) or within a second measurement module that measures temperature.

[0126] The second temperature sensor (TS2) may be arranged on one side or the other side of the NV diamond structure (10). As another example, a plurality of second temperature sensors (TS2) may be arranged on one side and the other side of the NV diamond structure (10).

[0127] The first temperature sensor (TS1) disposed on the first substrate (100) can be implemented using an element whose electrical properties, such as resistance, change depending on temperature. The first temperature sensor (TS1) can be implemented using at least one of a silicon temperature sensor, a thermistor, an RTD, and a thermocouple that utilizes the temperature dependency of the base voltage (Vbe) of the transistor. The second temperature sensor (TS2) disposed on the second substrate (100b) can also be implemented using an element whose electrical properties, such as resistance, change depending on temperature. The second temperature sensor (TS2) can be implemented using at least one of a silicon temperature sensor, a thermistor, an RTD, and a thermocouple that utilizes the temperature dependency of the base voltage (Vbe) of the transistor.

[0128] Meanwhile, the quantum sensor system according to the present specification can perform spin control at a frequency with different light intensities depending on temperature changes. In this regard, Fig. 13 illustrates changes in light intensity according to spin states in the quantum sensor system according to the present specification. Referring to Fig. 13, the light intensity has different values ​​depending on the spin state.

[0129] Fig. 14 is a conceptual diagram illustrating a method for continuously measuring a magnetic field using an interferometer according to a first embodiment. Referring to Fig. 14(a), spin control can be performed in the horizontal and vertical axes directions using an RF signal between the initialization section (R1) and the detection section (R2) of the optical signal. Referring to Fig. 14(b), it can be seen that the magnetic field values ​​of the horizontal and vertical axes change periodically as time changes. In addition, it can be seen that the peak values ​​of the magnetic field values ​​of the horizontal and vertical axes gradually decrease as time changes.

[0130] Fig. 15 illustrates a conceptual diagram of an oscillation period measurement method according to a second embodiment. Referring to Fig. 15(a), spin control can be performed using an RF signal between the initialization section (R1) and the detection section (R2) of the optical signal. Referring to Fig. 15(b), it can be seen that the Florence contrast changes periodically as time changes. In addition, it can be seen that the peak value of the Florence contrast gradually decreases as time changes.

[0131] Referring to Fig. 14, Ramsey interferometry can be used when measuring a continuous magnetic field or a low-frequency magnetic field. Referring to Fig. 15, Rabi oscillation period measurement can be used for magnetic field spin control. When measuring the Rabi oscillation period, spin can be controlled using an RF signal at the center frequency of the NV diamond structure for strong spin control. The center frequency of the NV diamond structure can be set to 2.87 GHz.

[0132] Referring to FIGS. 6, 13, and 15, when the center frequency is shifted due to a temperature change, the number of quanta changing to a ±1 spin state decreases when spin is controlled with an RF signal of the same frequency. Therefore, spin control is attempted with a frequency having a different light intensity than before the temperature change. Accordingly, spin control can be performed with the existing center frequency of 2.87 GHz using the value measured by the second temperature sensor (TS2) adjacently arranged in the NV diamond structure (10) if there is no temperature difference or it is less than a threshold value. On the other hand, if a temperature difference occurs, spin control can be performed with a frequency of 2.87 + 74.2 (0.0742) * T GHz.

[0133] In this regard, the main circuit (1200) can track changes in electrical properties according to the single quantum spin structure of a single photon of the NV diamond structure (10). The main circuit (1200) can track transitions in resonant frequency according to the single quantum spin structure of a single photon of the NV diamond structure (10) in conjunction with the first and second temperature sensors (TS1, TS2).

[0134] Accordingly, the main circuit (1200) can perform spin control of the diamond structure (10) at the resonant frequency if the amount of change in temperature measured by the second temperature sensor (TS2) disposed on the second substrate (100b) adjacent to the NV diamond structure (10) is less than a threshold value. Here, the resonant frequency may correspond to the center frequency of 2.87 GHz. The threshold value of the amount of change in temperature may be set to a value at which no temperature change can be considered within the noise level level. Meanwhile, the main circuit (1200) can perform spin control of the diamond structure (10) at a changed frequency that adds up the amount of change in frequency proportional to the amount of change in temperature at the resonant frequency if the amount of change in temperature measured by the second temperature sensor (TS2) is greater than or equal to the threshold value. The amount of change in frequency proportional to the amount of change in temperature may correspond to 2.87 + 74.2 (0.0742) * T GHz.

[0135] Referring to FIG. 6, FIG. 13 to FIG. 15, the main circuit (1200) can track the transition of the resonant frequency according to the single quantum spin structure of a single photon of the NV diamond structure (10) in conjunction with the first and second temperature sensors (TS1, TS2). The main circuit (1200) can detect the maximum signal size of the resonator when oscillating by a single photon according to the transition of the resonant frequency. The main circuit (1200) can minimize the control error of the single photon by adjusting the resonant frequency based on the difference in the maximum signal size and the temperature value.

[0136] Meanwhile, the main circuit (1200) can track changes in electrical properties (e.g., resonance frequency shift) according to the multiple quantum spin structure of the ensemble NV diamond structure in conjunction with the first and second temperature sensors (TS1, TS2). The main circuit (1200) can control multiple quantum spins of multiple quanta of the ensemble NV diamond structure in the NV diamond structure (10). The main circuit (1200) can detect the maximum signal size of the resonator when oscillating by multiple photons according to the transition of the resonance frequency. The main circuit (1200) can minimize the control error of the multiple photons by adjusting the resonance frequency based on the difference between the maximum signal size and the temperature value. The ensemble NV diamond structure can correspond to an NV diamond structure according to different quantum spin states, as shown in FIG. 6 or FIG. 7.

[0137] Meanwhile, the quantum sensor system according to the present specification may be configured to compensate for the time-dependent decrease in light intensity of an optical signal from a light source. In this regard, FIG. 16 illustrates a graph showing the time-dependent decrease in light intensity of an optical signal of a quantum sensor system according to the present specification and a graph compensating for the light intensity decrease. FIG. 16(a) is a graph showing the time-dependent decrease in light intensity of an optical signal of a quantum sensor system. FIG. 16(b) is a graph showing the time-dependent decrease in light intensity of an optical signal of a quantum sensor system.

[0138] Low-power operation of a quantum sensor system requires the on / off switching of a light source. However, due to the characteristics of LED light sources, even at the same current, the light intensity in the on state can decrease slightly over time, as shown in the graph in Figure 16(a).

[0139] Referring to FIG. 6 and FIG. 16(a), the main circuit (1200) can detect the ratio of the light quantity decrease over time of the light signal from the light source (510) through a residue fitting algorithm in conjunction with the photodetector (420). In this regard, if the X-axis is set to time and the Y-axis is set to the light quantity, the following relationship can be established: Y = -0.0685*X + 3133.1. The main circuit (1200) can detect the ratio of the light quantity decrease over time of the light signal through a residue fitting algorithm.

[0140] The main circuit (1200) can compensate for the decrease in light intensity over time through a residual analysis algorithm. In this regard, residual calculation and analysis can be performed after polynomial fitting of the raw data of the optical signal of the light source (510). Through residual calculation and analysis, the ODMR (Optically Detected Magnetic Resonance) graph signal can be restored.

[0141] Referring to FIG. 6 and FIG. 16(b), the main circuit (1200) can control the light source (510) so that the light quantity of the light source (510) increases over time so as to compensate for the light quantity decrease over time of the light signal. Accordingly, the light quantity of the light source (510) can be maintained at a constant level in all time intervals. To this end, the main circuit (1200) can control the initial driving and light quantity attenuation phenomenon of the light source (510) so as to compensate for the light quantity decrease over time of the light signal. The main circuit (1200) can control the initial driving and light quantity attenuation phenomenon of the light source (510) through a residual analysis algorithm.

[0142] The above describes a quantum sensor system for measuring magnetic fields. The technical benefits of this quantum sensor system are as follows.

[0143] According to the present specification, a quantum sensor system that measures a magnetic field through an NV diamond structure can reduce magnetic field measurement errors due to changes in ambient temperature.

[0144] According to the present specification, a magnetic field measurement error due to a change in ambient temperature can be reduced through a first temperature sensor provided in a main circuit and a second temperature sensor positioned adjacent to an NV diamond structure.

[0145] According to the present specification, a magnetic field measurement error due to an increase in the ambient temperature of an NV diamond structure when a light source of a specific wavelength is irradiated can be reduced through a first temperature sensor provided in a main circuit and a second temperature sensor positioned adjacent to an NV diamond structure.

[0146] Further scope of the applicability of this specification will become apparent from the detailed description below. However, since various changes and modifications within the spirit and scope of this specification will be apparent to those skilled in the art, it should be understood that the detailed description and specific examples, such as preferred embodiments, are given by way of example only.

Claims

1. In quantum sensor systems, A magnetic sensor module disposed spaced apart from the magnetic device to measure a magnetic field from the magnetic device and having a second temperature sensor; and A main circuit operatively coupled to the magnetic sensor module and comprising a first temperature sensor, The above main circuit is, A quantum sensor system configured to measure the magnetic field in a specific frequency band based on a temperature value difference between a first temperature value measured by the first temperature sensor and a second temperature value measured by the second temperature sensor.

2. In paragraph 1, The above magnetic sensor module, A first substrate on which a light source is arranged; and A second substrate is disposed spaced apart from the first substrate in the vertical axis direction, and includes an NV diamond structure and the first temperature sensor. A quantum sensor system, wherein a photodetector is arranged to be spaced apart from the second substrate in the vertical axis direction and configured to detect a signal emitted from the NV diamond structure, and is provided in the magnetic sensor module or the main circuit.

3. In paragraph 2, Further comprising a lock-in amplifier configured to amplify a signal from the photodetector and output an output signal, The above main circuit is, A quantum sensor system that measures the magnetic field according to the slope of the output signal according to the frequency change in the first frequency band when the difference in the above temperature values ​​is less than the critical temperature difference.

4. In paragraph 3, The above main circuit is, If the difference in the above temperature values ​​is greater than or equal to the critical temperature difference, the magnetic field is measured according to the slope of the output signal according to the frequency change in the second frequency band, A quantum sensor system, characterized in that the second frequency band is a lower frequency band than the first frequency band.

5. In paragraph 3, The above main circuit is, A quantum sensor system that measures a magnetic field in the specific frequency band or changes the specific frequency band in which the magnetic field is to be measured based on the updated temperature value difference between the updated first temperature value and the updated second temperature value.

6. In paragraph 5, The above main circuit is, A quantum sensor system that controls the magnetic sensor module to measure the magnetic field at the resonant frequency of the magnetic sensor module when the difference in the updated temperature values ​​is less than the threshold temperature difference.

7. In paragraph 5, The above main circuit is, If the difference in the updated temperature value is greater than or equal to the threshold temperature difference, the magnetic sensor module is controlled so that the resonant frequency of the magnetic sensor module shifts according to the difference in the updated temperature value, A quantum sensor system that controls the magnetic sensor module to measure the magnetic field at the above-described transition resonant frequency.

8. In paragraph 7, The magnetic sensor module comprises a resonator formed on the first substrate on which the light source is arranged and configured to radiate an RF signal; and Further comprising an RF generator that generates the RF signal and applies it to the resonator, A sensor system wherein the main circuit controls the RF generator to generate the RF signal at the shifted resonant frequency.

9. In paragraph 8, The above main circuit is, Calculate the frequency shift value according to the difference in the above updated temperature value, Calculate the value obtained by dividing the above calculated frequency shift value by the minimum frequency sweep interval, Controlling the RF generator to generate the RF signal at the shifted resonant frequency having a frequency shift interval of an integer multiple adjacent to the divided value calculated above, A quantum sensor system that controls the operating frequency band of the lock-in amplifier to measure the magnetic field at the shifted resonant frequency.

10. In paragraph 8, The above magnetic sensor module, A quantum sensor system that controls the RF generator so that the first resonant frequency of the resonator disposed on the first substrate is changed based on the updated temperature value difference when the updated temperature value difference is greater than or equal to the threshold temperature difference.

11. In paragraph 2, The first temperature sensor is disposed inside the processor of the main circuit or inside the measurement module that measures the temperature, The second temperature sensor is disposed inside the processor within the magnetic sensor module or inside the second measurement module that measures the temperature, A quantum sensor system, wherein the second temperature sensor is disposed on one side or the other side of the NV diamond structure.

12. In paragraph 2, A quantum sensor system wherein the NV diamond structure is arranged in the slot region of the second substrate so that light from the light source emitted through the slot region of the second substrate is incident thereon.

13. In paragraph 2, A quantum sensor system, characterized in that the light source is an LED light source, a laser light source, an infrared light source, or an ultraviolet light source in the visible light range.

14. In paragraph 2, The above first temperature sensor detects changes in the external temperature due to heat generated from the processor of the main circuit, The above main circuit controls the magnetic sensor module so that the transition value of the resonance frequency of the NV diamond structure due to the change in the external temperature decreases, A quantum sensor system in which the sensitivity of magnetic field measurement from the magnetic device decreases as the transition value of the resonant frequency decreases.

15. In paragraph 2, A quantum sensor system, wherein the first temperature sensor and the second temperature sensor are implemented as at least one of a silicon temperature sensor, a thermistor, an RTD, and a thermocouple that utilizes the temperature dependence of the base voltage (Vbe) of a transistor.

16. In paragraph 8, The above main circuit is, Tracking the transition of the resonant frequency according to the single quantum spin structure of a single photon of the NV diamond structure in conjunction with the first and second temperature sensors, Detecting the maximum signal size of the resonator when oscillating by the single photon according to the transition of the resonant frequency, A quantum sensor system that minimizes the control error of the single photon by adjusting the resonant frequency based on the difference in the maximum signal size and the temperature value.

17. In paragraph 8, The above main circuit is, Tracking the transition of the resonant frequency according to the multiple quantum spin structure of the multi-photon of the ensemble NV diamond structure within the NV diamond structure in conjunction with the first and second temperature sensors, Detecting the maximum signal size of the resonator when oscillating by the multiple photons according to the transition of the resonant frequency, A quantum sensor system that minimizes the control error of the multi-photon by adjusting the resonant frequency based on the difference in the maximum signal size and the temperature value.

18. In paragraph 14, The above main circuit is, If the temperature change measured by the second temperature sensor disposed on the second substrate adjacent to the NV diamond structure is less than a threshold value, spin control of the diamond structure is performed at the resonant frequency, A quantum sensor system that performs spin control of the diamond structure at a changed frequency that adds a frequency change proportional to the temperature change amount at the resonant frequency when the temperature change amount measured by the second temperature sensor is greater than a threshold value.

19. In paragraph 2, Further comprising an electromagnetic shielding sheet placed on the substrate of the main circuit to shield power noise, The above electromagnetic wave blocking sheet is placed adjacent to the periphery of the photo detector, A quantum sensor system, characterized in that the electromagnetic wave shielding sheet is a ferrite sheet or a sheet having properties different from ferrite.

20. In the second paragraph, The above main circuit is, In conjunction with the above photo detector, the ratio of the light quantity decrease over time of the light signal from the light source is detected through a residual fitting algorithm, A quantum sensor system that controls the initial operation and light intensity attenuation phenomenon of the light source through a residue analysis algorithm so that the light intensity decrease over time of the above optical signal is compensated for.

Images