Magnetic sensing device based on diamond nitrogen-vacancy sensor

Abstract

The invention relates to a magnetic sensing device based on a diamond nitrogen-vacancy sensor. The magnetic sensing device based on the diamond nitrogen-vacancy sensor according to one embodiment of the present invention comprises: a classic sensor for sensing a magnetic field signal; the quantum sensor is used for sensing a magnetic field signal through the quantum phase of electron spinning of the diamond nitrogen-vacancy sensor with negative electricity in the diamond crystal; and a control unit that senses a magnetic field signal using the classic sensor and the quantum sensor.

Description

Technical Field

[0001] The present invention relates to a magnetic sensing device based on a diamond nitrogen-vacancy sensor, and more particularly, to a device for sensing a magnetic field using a classical sensor for sensing a magnetic field and a quantum sensor including a diamond nitrogen-vacancy sensor. Background Art

[0002] Diamond crystals are made of carbon atoms, but if carbon atoms are replaced by other types of atoms, lattice defects will occur. One of these defects is a nitrogen-vacancy center, where a carbon atom is replaced by a nitrogen atom and the adjacent carbon atom is missing, forming a vacancy.

[0003] A diamond nitrogen-vacancy center (DNV) has an electron spin with spin number S=1, and its spin quantum can have three spin states (ms): +1, 0, and -1. In the absence of an external magnetic field axially along the nitrogen-vacancy center within the diamond, the spin quantum states of the +1 and -1 spin states (ms) overlap and are at similar energy levels. However, in the presence of an external magnetic field axially along the nitrogen-vacancy center within the diamond, the Zeeman effect causes the overlap of the +1 and -1 spin quantum states (ms) to disappear, and the states are at different energy levels. Therefore, the nitrogen-vacancy spin quantum has two resonant frequencies, corresponding to spin transitions between the spin states ms=0 and ms=+1, or between the spin states ms=0 and ms=-1. The difference between the two resonant frequencies is proportional to the magnitude of the external magnetic field.

[0004] When diamond nitrogen-vacancy sites are irradiated with laser light of 532 nm, the excited quanta in the spin state ms = 0 emit red light at wavelengths above 600 nm and return to the ground state. However, the quanta in the spin states ms = +1 and ms = -1 do not emit red light after being excited, but instead change to the spin state ms = 0 and return to the ground state. Therefore, the amount of red fluorescence emitted is proportional to the number of spin quanta in the spin state ms = 0.

[0005] If two resonant frequencies corresponding to spin transitions are applied to diamond nitrogen-vacancy sites, a spin transition from spin state ms=0 to spin state ms=+1 or spin state ms=-1 is induced, thereby reducing the number of quanta in spin state ms=0 and the amount of emitted red fluorescence.

[0006] Therefore, by applying varying microwave frequencies to diamond nitrogen-vacancy sites and recording the frequency-dependent changes in fluorescence, an ODMR (Optically Detected Magnetic Resonance) spectrum can be obtained, showing a decrease in fluorescence at the resonance frequencies corresponding to the respective spin transitions. The magnitude of the magnetic field applied to the diamond nitrogen-vacancy sites can be determined based on the difference between the two resonance frequencies at which fluorescence decreases in this ODMR spectrum.

[0007] On the other hand, in order to sense the magnetic field signals from the human body, a resolution of femtotesla (10-15T) is required. Currently, the only available sensor is the SQUID (Superconducting quantum interference device) sensor used for MRI, which is used to diagnose brain and heart diseases.

[0008] Since SQUID utilizes superconductivity, it requires a large additional system such as a cryogenic system using liquid helium or liquid nitrogen to maintain an extremely low temperature environment.

[0009] Since quantum sensors operate at SQUID-level resolution at room temperature, they are conducive to miniaturization and can be used in low-cost alternative MRI equipment for diagnosing brain and heart diseases, as well as technologies that measure and analyze a person's thoughts or state through brain signal detection / analysis and then transmit them to a computer to operate things according to intention, namely BCI (Brain-Computer Interface).

[0010] For BCI applications, measurements and analysis must be performed instantly and immediately under normal circumstances, rather than performing rigorous measurements in a space where external magnetic field signals are limited, as in medical MRI. Summary of the Invention

[0011] Problems to be solved by the invention

[0012] An object of the present invention is to provide a quantum sensor including a diamond nitrogen-vacancy sensor using a lock-in amplifier (Lock-in Amplifier) ​​technology for signals in order to reduce environmental noise.

[0013] Another object of the present invention is to provide a magnetic sensing device based on a diamond nitrogen-vacancy sensor, which can improve the magnetic field resolution by utilizing existing classical sensors for sensing magnetic fields and quantum sensors including diamond nitrogen-vacancy sensors.

[0014] Technical solutions to the problem

[0015] To achieve the above-mentioned objectives, a magnetic sensing device based on a diamond nitrogen-vacancy sensor according to an embodiment of the present invention includes: a classical sensor for sensing a magnetic field signal; a quantum sensor for sensing a magnetic field signal through the quantum phase of the electron spin of the negatively charged diamond nitrogen-vacancy sensor within the diamond crystal; and a control unit for sensing the magnetic field signal using the classical sensor and the quantum sensor.

[0016] In an embodiment, the quantum sensor includes: a diamond nitrogen-vacancy sensor; a frequency generator that outputs a reference frequency; a microwave generator that modulates the frequency based on the reference frequency to generate microwaves that induce spin transitions in the diamond nitrogen-vacancy sensor; a laser irradiation unit that applies laser light for exciting spin quanta to the diamond nitrogen-vacancy sensor; a detector that detects a fluorescent signal output by the diamond nitrogen-vacancy sensor; and a lock-in amplifier that determines the reference frequency to be output from the frequency generator based on the signal output by the detector.

[0017] In an embodiment, the quantum sensor further includes: a first filter that transmits only laser light in a first wavelength region of the laser light output by the laser irradiation unit; and a second filter that transmits only fluorescent signals in a second wavelength region of the fluorescent signals output by the diamond nitrogen-vacancy sensor.

[0018] In an embodiment, the lock-in amplifier extracts the original signal component using trigonometric function characteristics.

[0019] In an embodiment, the quantum sensor has different resolutions depending on the reference frequency in the same magnetic field region.

[0020] In an embodiment, the greater the amplitude of the change in the signal measured by the quantum sensor in the magnetic field region, the higher the resolution.

[0021] In an embodiment, the control unit divides the magnetic field area to be measured into multiple areas, uses the classical sensor to determine the change amplitude of the magnetic field signal, and determines the reference frequency used in the measurement in the quantum sensor based on the change amplitude of the signal determined in each of the multiple areas.

[0022] In an embodiment, the control unit controls the quantum sensor to perform magnetic field sensing using a first reference frequency in a first region of the plurality of regions, and controls the quantum sensor to perform magnetic field sensing using a second reference frequency different from the first reference frequency in a second region of the plurality of regions different from the first region.

[0023] In an embodiment, the control unit measures the magnetic field strength using the classical sensor and the quantum sensor, and extracts the signal to be measured from the signal including noise measured by the quantum sensor using the signal measured by the classical sensor.

[0024] In an embodiment, the control unit measures the magnetic field intensity using the classical sensor and the quantum sensor, respectively, regardless of the order of the classical sensor and the quantum sensor.

[0025] Effects of the Invention

[0026] According to the present invention, a new magnetic field sensing method can be provided, which sets the quantum sensor to an optimized measurement frequency for each magnetic field region to be measured using a classical sensor, thereby being able to provide optimized resolution. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Schematic diagram of the energy levels of nitrogen-vacancy sites in diamond.

[0028] Figure 2 This is a diagram showing an example of generating an ODMR (Optical Detected Magnetic Resonance) spectrum.

[0029] Figure 3 1 is a diagram showing an example of applying microwaves frequency-modulated with a specific reference signal and acquiring an ODMR spectrum by phase-comparing only the reference signal component in a signal generated in a photodetector.

[0030] Figure 4 : is a diagram showing an example of the output of a lock-in amplifier.

[0031] Figure 5 This is a conceptual diagram for explaining a magnetic sensor device according to an embodiment of the present invention.

[0032] Figure 6 FIG. 1 is a conceptual diagram illustrating a quantum sensor including a diamond nitrogen-vacancy sensor according to an embodiment of the present invention.

[0033] Figure 7 、 Figure 8 、 Figure 9 、 Figure 10 、 Figure 11 as well as Figure 12 This is a conceptual diagram for explaining the change in magnetic field resolution caused by a change in measurement frequency of a diamond nitrogen-vacancy sensor according to one embodiment of the present invention.

[0034] Figure 13FIG. 1 is a flowchart for illustrating a method for sensing a magnetic field using a classical sensor and a quantum sensor according to an embodiment of the present invention.

[0035] Figure 14 is a conceptual diagram for illustrating a method for sensing a magnetic field using a classical sensor and a quantum sensor according to another embodiment of the present invention. DETAILED DESCRIPTION

[0036] Hereinafter, the embodiments disclosed in this specification will be described in detail with reference to the accompanying drawings. Regardless of the figure numbers, the same or similar structural elements are given the same figure marks, and repeated descriptions thereof are omitted. The suffixes "module" and "section" of the structural elements used in the following description are only given or mixed for the convenience of writing the description, and they themselves do not have mutually distinguishable meanings or functions. In addition, in the process of describing the embodiments disclosed in this specification, when it is judged that the specific description of the relevant known technology will confuse the gist of the embodiments disclosed in this specification, the detailed description of the known technology is omitted. In addition, the drawings are only used to help understand the embodiments disclosed in this specification. The technical ideas disclosed in this specification are not limited to the drawings, and should be understood to include all changes, equivalents and substitutes within the scope of the ideas and technology of the present invention.

[0037] Terms including ordinal numbers such as first, second, etc. can be used to describe various structural elements, but these structural elements are not limited to these terms. These terms are used only to distinguish one structural element from another structural element.

[0038] When a structural element is referred to as being “connected” or “engaged” to another structural element, it should be understood that, although the structural element may be directly connected or engaged to the other structural element, other structural elements may exist between them. Conversely, when a structural element is referred to as being “directly connected” or “directly engaged” to another structural element, it should be understood that no other structural elements exist between them.

[0039] Unless the context clearly indicates otherwise, an expression in the singular includes an expression in the plural.

[0040] In this application, the terms "including" or "having" should be understood as indicating the existence of the features, numbers, steps, actions, structural elements, parts or their combinations disclosed in this specification, and are not intended to preclude the existence or additional possibilities of one or more other features, numbers, steps, actions, structural elements, parts or their combinations.

[0041] The magnetic sensing device based on the diamond nitrogen-vacancy sensor described in this specification can be implemented in the form of a mobile phone, a smart phone, a laptop computer, a digital broadcasting terminal, a PDA (personal digital assistant), a PMP (portable multimedia player), a navigation, a slate PC, a tablet PC, an ultrabook, a wearable device (e.g., a smartwatch, a smart glass), an HMD (head mounted display), etc.

[0042] Figure 1 is a schematic diagram showing the energy levels of diamond nitrogen-vacancy sites.

[0043] Reference Figure 1 The spin quantum of the diamond nitrogen-vacancy has a ground state 210 comprising a spin triplet state, including three spin states: spin state ms = 0, and the mutually symmetrical spin states ms = +1 and ms = -1. In the absence of a magnetic field, the spin states ms = +1 and ms = -1 are in the same energy state, separated by a predetermined energy level from the spin state ms = 0, due to the spin-spin interaction. In the absence of a magnetic field, the energy level of the spin state ms = 0 is separated by approximately 2.87 GHz from the energy levels of the spin states ms = +1 and ms = -1.

[0044] If an external magnetic field is applied in the ground state 210 , the energies of the spin state ms=+1 and the spin state ms=−1, which once had the same energy, have energy levels 250 separated in proportion to the magnitude of the external magnetic field.

[0045] When the spin quantum of the diamond nitrogen-vacancy site in the ground state 210 is irradiated with green light, it is excited to the excited state 220. The green light can have a wavelength of 637 nm or less, but preferably has a wavelength of 532 nm. In this case, the spin quantum of the diamond nitrogen-vacancy site is excited while maintaining its own spin state.

[0046] The spin quanta in the excited state 220 return to the ground state 210, but most of the spin quanta in the spin state ms=0 return to the ground state 210 (241) in the spin state ms=0 while emitting red light (e.g., above 600nm and below 900nm) photons, while a part of them return to the ground state 210 (243) via the singlet state 230. In the case of passing through the singlet state 230, red light will not be emitted and the spin quanta return to the ground state 210.

[0047] Most of the spin quanta of the diamond nitrogen-vacancy sites in the excited state 220, in the spin state ms = +1 and the spin state ms = -1, return to the ground state 210 via the singlet state 230. During this return, they do not return to the original spin state ms = ±1, but rather to the spin state ms = 0. Therefore, when irradiated with green light, after a predetermined period of time, most of the spin quanta of the diamond nitrogen-vacancy sites have the spin state ms = 0.

[0048] On the other hand, if a resonant frequency corresponding to the energy difference between spin states ms = 0 and ms = +1, or between spin states ms = 0 and ms = -1, is applied to spin state ms = 0, a spin transition from spin state ms = 0 in ground state 210 to spin state ms = +1 or spin state ms = -1 is induced. Under the influence of an external magnetic field B, each resonant frequency F is determined by F = D ± ηB. Here, D is the resonant frequency in the absence of a magnetic field, i.e., the zero magnetic field separation resonant frequency, which is 2.87 GHz, and η is the electron spin gyrometry ratio, which is 28 MHz / mT.

[0049] If green light (e.g., light with a wavelength of 532 nm) is applied to the spin quantum of the ground state 210 of the diamond nitrogen-vacancy, it is excited to the excited state 220. Most of the spin quanta of the excited state 220, the spin state ms = +1 and the spin state ms = -1, pass through Figure 1 243 does not emit red light and returns to the ground state 210. Most of the spin quanta of the excited state 220 with spin state ms=0 pass through Figure 1 241 emits red light above 600nm and returns to the ground state 210. At this time, the spin quantum in the spin state ms=±1 converts to the spin state ms=0 and returns to the ground state 210, while maintaining the spin state of the spin quantum in the spin state ms=0.

[0050] Therefore, if an ODMR (optically-detected magnetic resonance) spectrum that records changes in the amount of emitted light is recorded using a photodiode while changing the wavelength of the applied microwaves, a portion with a lower amount of light can be observed at two resonant frequencies corresponding to the energy difference between the spin state ms=0 and the spin state ms=+1 and the energy difference between the spin state ms=0 and the spin state ms=-1.

[0051] Figure 2 This is a diagram showing an example of an ODMR spectrum.

[0052] Reference Figure 2In the ODMR spectrum, the measured light amount is low at the two resonance frequencies corresponding to the energy difference 263 between the spin state ms = 0 and the spin state ms = +1 or the energy difference 261 between the spin state ms = 0 and the spin state ms = -1. If a frequency other than the corresponding resonance frequency is applied, the spin state ms = 0 in the ground state 210 is not excited to the spin state ms = +1 or the spin state ms = -1, but remains in the spin state ms = 0. In addition, if green light is used to excite the excited state 220, the spin quantum of the diamond nitrogen-vacancy maintaining the spin state ms = 0 is excited. Figure 1 The red light photon is emitted through the path 241 and returns to the ground state 210. On the contrary, if the corresponding resonance frequency is applied, the spin quantum of the spin state ms = 0 in the ground state 210 is converted to the spin state ms = +1 or the spin state ms = -1, and is excited to the excited state 220 by green light again. Figure 1 The ODMR spectrum is measured by the photodiode, which emits no red light photons along the 243 path and returns to the ground state 210, resulting in a decrease in the amount of light measured by the photodiode. Therefore, when measuring the ODMR spectrum, the measured light intensity is low at two resonant frequencies corresponding to the energy difference 263 between the spin state ms = 0 and the spin state ms = +1, and the energy difference 261 between the spin state ms = 0 and the spin state ms = -1. Furthermore, the difference between these two frequency bands is proportional to the strength of the magnetic field applied to the diamond nitrogen-vacancy. Therefore, the diamond nitrogen-vacancy can be used to detect the presence of a magnetic field or changes in a magnetic field.

[0053] like Figure 2 When acquiring ODMR spectra as shown, frequency modulation techniques can be used to improve the signal-to-noise ratio.

[0054] Figure 3 FIG. 1 is a diagram showing an example of acquiring an ODMR spectrum by applying microwaves frequency-modulated with a specific reference signal and performing phase comparison on only the reference signal component in the signal generated in the photodetector. Figure 4 : is a diagram showing an example of the output of a lock-in amplifier.

[0055] Reference Figure 3 If microwaves 170 are applied that have been frequency-modulated with a reference signal at a frequency other than the resonant frequency, there is almost no slope, and therefore the signal generated by the photodetector contains almost no reference signal component. In contrast, if microwaves 180 are applied that have been frequency-modulated with a reference signal at the resonant frequency, the slope in the corresponding region becomes larger, and therefore the reference signal component appears in the signal detected by the photodetector.

[0056] Therefore, if a lock-in amplifier (LIA) capable of extracting the frequency of the reference signal is used, the reference signal can be detected. Figure 3 The frequency modulation shown can relatively enhance the reference signal, thereby getting rid of the influence of noise existing in the low frequency band of the signal and improving the signal-to-noise ratio.

[0057] like Figure 3 It can be seen that the magnitude of the signal input to the lock-in amplifier is proportional to the slope of the ODMR spectrum. Therefore, the signal output of the lock-in amplifier obtained by frequency modulation has the differential form of the original ODMR spectrum, forming Figure 4 Therefore, if the signal is detected Figure 4 The change in the lock-in amplifier output shown can detect the change in the external magnetic field.

[0058] On the other hand, the present invention can provide a magnetic sensing device that utilizes not only a quantum sensor including a diamond nitrogen-vacancy sensor but also an existing classical sensor for sensing a magnetic field (eg, a magnetic sensor), thereby significantly improving the resolution of sensing a magnetic field.

[0059] Figure 5 This is a conceptual diagram for explaining a magnetic sensor device according to an embodiment of the present invention.

[0060] The magnetic sensing device of the present invention may include: a classical sensor 200 for sensing magnetic field signals; a quantum sensor 300 for sensing magnetic field signals through the quantum phase of the electron spin of a negatively charged diamond nitrogen-vacancy sensor within a diamond crystal; and a control unit 400 for sensing magnetic field signals using the classical sensor and the quantum sensor.

[0061] The control unit 400 can implement a magnetic sensing technology capable of wide bandwidth and precise measurement by using a hybrid sensing method of the classical sensor 200 and the quantum sensor 300 .

[0062] Figure 6 FIG. 1 is a conceptual diagram illustrating a quantum sensor including a diamond nitrogen-vacancy sensor according to an embodiment of the present invention.

[0063] Reference Figure 6(a) The quantum sensor 300 included in the magnetic sensing device of the present invention may include: a diamond nitrogen-vacancy sensor 310; a frequency generator (RF (Radio Frequency)-Generator) 320 that outputs a reference frequency (or reference signal); a microwave generator 330 that modulates a frequency based on the reference frequency to generate microwaves that induce spin transitions in the diamond nitrogen-vacancy sensor; a laser irradiation unit 340 that applies laser light for exciting spin quanta to the diamond nitrogen-vacancy sensor; a detector (Phto-Detector (PD)) 350 that detects a fluorescent signal output by the diamond nitrogen-vacancy sensor; and a phase-locked amplifier (Lock-in Amplifier) ​​360 that determines the reference frequency output by the frequency generator based on the signal output by the detector.

[0064] In addition, the quantum sensor 300 may further include: a first filter 370 that only transmits laser light in a first wavelength region (for example, laser light with a wavelength of 532 nm) in the laser light output by the laser irradiation unit; and a second filter 380 that only transmits fluorescent signals in a second wavelength region (for example, fluorescent signals outputting red light above 600 nm) in the fluorescent signals output by the diamond nitrogen-vacancy sensor.

[0065] Frequency generator (or reference frequency generator) 320 can generate a reference signal for frequency modulation. According to one embodiment, the reference frequency can be between 1 kHz and 100 kHz. Frequency generator 320 can transmit the generated reference signal to microwave generator 330 and lock-in amplifier 360. The reference signal can represent a signal having a reference frequency. The reference signal transmitted to microwave generator 330 is also transmitted to lock-in amplifier 360 and can serve as a comparison target for the signal to be detected by lock-in amplifier 360.

[0066] The microwave generator 330 can generate microwaves obtained by modulating the following two microwaves based on the reference signal: microwaves having a first resonant frequency that causes the spin quantum of the diamond nitrogen-vacancy sensor 310 to spin-transition from the spin state ms=0 to the spin state ms=-1; and microwaves having a second resonant frequency that causes the spin quantum to spin-transition from the spin state ms=0 to the spin state ms=+1.

[0067] The quantum sensor may further include a power amplifier (not shown) that amplifies the microwave signal generated by the microwave generator 330 and then inputs the amplified signal to the diamond nitrogen-vacancy sensor 310 .

[0068] The laser irradiation unit 340 may irradiate the diamond nitrogen-vacancy sensor 310 with laser light to excite the spin quantum from the ground state 110 to the excited state 120. As an example, the wavelength of the laser light may be 532 nm.

[0069] The spin quantum of the diamond nitrogen-vacancy sensor 310 can be triggered to undergo two spin transitions by the microwave signal generated and input by the microwave generator 330 . After being excited to the excited state 120 by the laser irradiation unit 340 , the quantum spin returns to the ground state 110 and generates fluorescence.

[0070] The lock-in amplifier 360 may receive the fluorescence signal generated by the diamond nitrogen-vacancy sensor 310 and output a comparison result between the fluorescence signal and a reference signal.

[0071] Reference Figure 6 (b) , there are a signal S to be measured and a noise signal N in the environment for measuring the magnetic field, and the signal measured by the detector is measured as a superposition signal (S+N) of the signal S and the signal N.

[0072] The lock-in amplifier 360 can extract the original signal component from the fluorescent signal S+N detected by the detector 350 using trigonometric function characteristics.

[0073] That is, the lock-in amplifier 360 can extract the original signal component using trigonometric function characteristics.

[0074] Figure 7 、 Figure 8 、 Figure 9 、 Figure 10 、 Figure 11 as well as Figure 12 This is a conceptual diagram for explaining how a change in the magnetic field resolution results from a change in the measurement frequency of a diamond nitrogen-vacancy sensor according to an embodiment of the present invention.

[0075] Reference Figure 7 From the ODMR spectrum shown in (a), it can be confirmed that the resonance frequency changes as the magnetic field strength increases.

[0076] As mentioned above, the magnitude of the signal input to the lock-in amplifier is proportional to the slope of the ODMR spectrum. Therefore, the signal output of the lock-in amplifier obtained by frequency modulation has the differential form of the original ODMR spectrum, forming Figure 7 The signal output is as shown in (b).

[0077] Therefore, if it is detected Figure 7 The output change of the lock-in amplifier shown in (b) can detect the change of the external magnetic field.

[0078] On the other hand, to detect magnetic fields below a specified intensity that are difficult for ODMR to detect / distinguish, the present invention can use a lock-in amplifier technology. In this case, the lock-in amplifier technology will cause the sensing resolution to vary depending on the magnetic field intensity and the reference frequency determined by the lock-in amplifier.

[0079] Specifically, the quantum sensor may exhibit different resolutions in the same magnetic field region due to different reference frequencies.

[0080] For example, Figure 8 As shown, when the lock-in amplifier 360 is set to different reference frequencies as ①, ② and ③, Figure 9 As shown, the output of the lock-in amplifier is different.

[0081] Reference Figure 10 (a) shows that the output of the lock-in amplifier on the right side using the reference frequency of ① detects more red light than the output of the lock-in amplifier on the left side using the reference frequency of ②. Figure 10 In (b), it can also be confirmed that the resolution varies with the change in the reference frequency.

[0082] The greater the amplitude of the change in the signal measured by the quantum sensor 300 in the magnetic field region, the higher the resolution may be.

[0083] Specifically, the control unit 400 can divide the magnetic field area to be measured into multiple areas, and use the classical sensor to determine the change amplitude of the magnetic field signal, and determine the reference frequency used by the quantum sensor for measurement based on the change amplitude of the signal determined in each of the multiple areas.

[0084] For example, the control unit 400 may control the quantum sensor to perform magnetic field sensing using a first reference frequency (the reference frequency with the largest variation range ② in region 1100) in the first region I (1100) of the plurality of regions I, II, and III.

[0085] In addition, the control unit 400 can control the quantum sensor to perform magnetic field sensing in a second region (the region between II and III) 1200 that is different from the first region in the multiple regions I, II, and III, using a second reference frequency (the reference frequency ① with the largest variation in region 1200) that is different from the first reference frequency.

[0086] Reference Figure 12 The result in the first area is that more red is detected when the reference frequency of ② is used compared to when the reference frequency of ① is used, so it can be confirmed that the resolution is improved.

[0087] Figure 13 is a flowchart for illustrating a method for sensing a magnetic field using a classical sensor and a quantum sensor according to an embodiment of the present invention.

[0088] As described above, after the present invention uses a classical sensor (existing magnetic sensor) to scan the magnetic field of each of a plurality of regions (S1310), it determines the reference frequency used by the quantum sensor to perform precise scanning (S1320), thereby significantly improving the resolution when sensing the magnetic field.

[0089] On the other hand, the magnetic sensing device of the present invention can also use the classical sensor and the quantum sensor to perform sensing at the same time, and then use the sensing results to extract the signal to be measured, rather than first scanning with the classical sensor and then scanning with the quantum sensor.

[0090] Specifically, the control unit 400 may use the classical sensor and the quantum sensor to measure the magnetic field strength, and use the signal measured by the classical sensor to extract the signal to be measured from the signal including noise measured by the quantum sensor.

[0091] At this time, the control unit 400 may measure the magnetic field intensity using the classical sensor and the quantum sensor, regardless of the order of the classical sensor and the quantum sensor.

[0092] Figure 14 is a conceptual diagram for explaining a method for sensing a magnetic field using a classical sensor and a quantum sensor according to another embodiment of the present invention.

[0093] Figure 14 (a) may include a signal including noise measured by a quantum sensor, Figure 14 (b) may include signals measured by classical sensors.

[0094] The control unit 400 can simultaneously use the classical sensor and the quantum sensor to measure the magnetic field strength, and then remove the large noise signal of μT to nT measured by the classical sensor from the signal including various noises. In this way, the present invention can improve the magnetic sensing performance.

[0095] The above diagrams and descriptions illustrate preferred embodiments of the present invention, but the present invention is not limited to the above-mentioned specific embodiments. Without departing from the spirit of the present invention as requested by the scope of the claims, ordinary technicians in the field to which the present invention belongs can perform various modified implementations, and these modified implementations cannot be understood separately from the technical ideas or expectations of the present invention.

Claims

1. A magnetic sensing device based on a diamond nitrogen-vacancy sensor, wherein: include: Classic sensor, used to sense magnetic field signals; A quantum sensor that senses magnetic field signals through the quantum phase of the electron spins of negatively charged diamond nitrogen-vacancy sensors within the diamond crystal; and The control unit uses the classical sensor and the quantum sensor to sense the magnetic field signal.

2. The magnetic sensing device based on the diamond nitrogen-vacancy sensor according to claim 1, characterized in that: The quantum sensor comprises: Diamond nitrogen-vacancy sensor; Frequency generator, outputs reference frequency; a microwave generator that modulates a frequency based on a reference frequency to generate microwaves that induce spin transitions in the diamond nitrogen-vacancy sensor; a laser irradiation unit for applying laser light for exciting spin quanta to the diamond nitrogen-vacancy sensor; a detector for detecting a fluorescent signal output by the diamond nitrogen-vacancy sensor; and A lock-in amplifier determines a reference frequency to be output from the frequency generator based on a signal output from the detector.

3. The magnetic sensing device based on the diamond nitrogen-vacancy sensor according to claim 2, characterized in that: The quantum sensor further comprises: a first filter that transmits only laser light in a first wavelength range among the laser light outputted from the laser irradiation unit; and The second filter transmits only the fluorescent signal in the second wavelength range among the fluorescent signals output by the diamond nitrogen-vacancy sensor.

4. The magnetic sensing device based on the diamond nitrogen-vacancy sensor according to claim 1, characterized in that: The lock-in amplifier utilizes trigonometric function characteristics to extract original signal components.

5. The magnetic sensing device based on the diamond nitrogen-vacancy sensor according to claim 2, characterized in that: The quantum sensor has different resolutions according to a reference frequency in the same magnetic field region.

6. The magnetic sensing device based on the diamond nitrogen-vacancy sensor according to claim 5, characterized in that: The greater the amplitude of the change in the signal measured by the quantum sensor in the magnetic field region, the higher the resolution.

7. The magnetic sensing device based on the diamond nitrogen-vacancy sensor according to claim 1, characterized in that: The control unit divides the magnetic field area to be measured into a plurality of areas, and uses the classical sensor to determine the amplitude of the change of the magnetic field signal. The control unit determines a reference frequency used in measurement in the quantum sensor based on a variation amplitude of the signal determined in each of the plurality of regions.

8. The magnetic sensing device based on the diamond nitrogen-vacancy sensor according to claim 7, characterized in that: The control unit controls the quantum sensor to perform magnetic field sensing using a first reference frequency in a first region of the plurality of regions. The control unit controls the quantum sensor to perform magnetic field sensing using a second reference frequency different from the first reference frequency in a second region different from the first region among the plurality of regions.

9. The magnetic sensing device based on the diamond nitrogen-vacancy sensor according to claim 1, characterized in that: The control unit measures the magnetic field strength using the classical sensor and the quantum sensor, The control unit extracts a signal to be measured from a signal including noise measured by the quantum sensor using the signal measured by the classical sensor.

10. The magnetic sensing device based on the diamond nitrogen-vacancy sensor according to claim 9, characterized in that: The control unit measures the magnetic field intensity using the classical sensor and the quantum sensor, regardless of the order of the classical sensor and the quantum sensor.

Images