An alternating magnetic field sensitive detection device and method based on sideband modulation of a resonator-magnon coupling system

Abstract

The present invention relates to an alternating magnetic field sensitive detection device and method based on sideband regulation of a resonator-magnon coupling system, comprising: a microwave source, a superconducting resonator, a YIG sphere, a filter, two signal amplifiers, a rectifying diode, a permanent magnet, and a signal readout system; the present invention realizes signal amplification of an alternating magnetic field through the resonator-magnon coupling system; realizes sensitive detection of an alternating magnetic field, and the detection sensitivity reaches pT / √Hz. The present invention utilizes a coupling system composed of a resonator and a magnetic material to develop a weak magnetic field sensitive detection device and method that can operate at liquid nitrogen temperature or room temperature and whose sensitivity is independent of size.

Description

Technical Field

[0001] The present invention relates to an alternating magnetic field sensitive detection device and method based on sideband regulation of a resonator-magnon coupling system, belonging to the technical field of magnetic field detection. Background Art

[0002] At present, magnetometers for detecting weak magnetic fields have been widely used, from condensed matter experiments, gravitational wave detection to nuclear magnetic resonance signal detection, paleomagnetism research, non-destructive testing and underwater object detection. The well-developed magnetometers include: fluxgate magnetometers, superconducting quantum interference devices, diamond color center magnetometers, atomic magnetometers, etc. These magnetometers are respectively suitable for different scenarios due to the limitations of their working principles.

[0003] Currently, the most sensitive magnetic field detectors are the atomic magnetometer developed based on the spin-exchange relaxation free (SERF) state of alkali metal atoms and the low-temperature superconducting quantum interference device (SQUIDs) developed based on Josephson junctions. Their detection sensitivity can reach below fT / √Hz. Therefore, they play a crucial role in ultra-high-precision magnetic field measurement. The SERF state is a special state of alkali metal atomic vapor. It refers to a nuclear magnetic resonance with an extremely low linewidth formed in alkali metal atomic vapor when the spin-exchange rate between alkali metal atoms is much greater than the Larmor precession frequency. There are two core parameters that determine the detection sensitivity of the SERF magnetometer: one is that the resonance linewidth of the SERF state is only 200 Hz, and the other is that the change rate of the SERF state frequency with the external magnetic field is 28 GHz / T. The former reflects the ultimate resolution of the SERF state in the frequency spectrum, while the latter reflects the response of the SERF state to the change of the external magnetic field. One of them is determined by the intrinsic properties of the SERF state, and the other is determined by the electron charge-to-mass ratio, and both are difficult to be further optimized. SQUIDs require low-temperature operation, while SERF magnetometers do not require low temperature, and their sensitivity is related to the volume. Summary of the Invention

[0004] Aiming at the current situation of sensitive magnetic detection technology, the present invention uses a coupling system composed of a resonator and a magnetic material to develop a weak magnetic field sensitive detection device and method that can operate at liquid nitrogen temperature or room temperature and whose sensitivity is independent of size.

[0005] The main technical problems solved by the present invention include: First, realizing signal amplification of the alternating magnetic field through a resonator-magnon coupling system; Second, realizing sensitive detection of the alternating magnetic field, and the detection sensitivity reaches pT / √Hz.

[0006] Term Explanation:

[0007] HackRFOne, a handheld microwave receiving and transmitting device with the ability of spectrum analysis, is mostly used in the radio amateur community.

[0008] The technical solution of the present invention is as follows:

[0009] An alternating magnetic field sensitive detection device based on sideband regulation of a resonator-magnon coupling system, comprising:

[0010] A microwave source, a superconducting resonator, a YIG sphere, a filter, two signal amplifiers, a rectifying diode, a permanent magnet, and a signal readout system;

[0011] The resonator-magnon coupling system includes a superconducting resonator and a YIG sphere, and the YIG sphere is placed at the center of the superconducting resonator; the microwave source generates monochromatic microwaves for driving the superconducting resonator and the YIG sphere. After being modulated by the alternating magnetic field to be measured, the output signal sequentially passes through the filter, two signal amplifiers, and the rectifying diode, and finally is measured by a voltmeter;

[0012] The superconducting resonator converts the magnitude of the alternating magnetic field into the intensity of the sideband signal through the coupling with the magnetic material;

[0013] Magnons, that is, the YIG sphere, are used to sense the alternating magnetic field. When the alternating magnetic field acts on the YIG sphere, through the coupling effect, the resonator-magnon coupling system driven by microwaves generates sideband signals. By measuring the intensity of the sideband signals, the magnitude of the alternating magnetic field can be deduced;

[0014] The filter filters out microwaves other than the signal to be measured and transmits monochromatic microwaves;

[0015] The signal amplifier amplifies the output signal to improve the signal-to-noise ratio;

[0016] The rectifying diode rectifies the output signal, and the voltage signal measured by the voltmeter reflects the magnitude of the alternating magnetic field;

[0017] The permanent magnet provides a bias magnetic field for the YIG sphere to cause precession of the YIG sphere;

[0018] The signal readout system is used to detect the intensity of the sideband signal.

[0019] Preferably according to the present invention, the superconducting resonator is any one of a microstrip line resonator, a split ring resonator, a dielectric resonator, and a microwave cavity.

[0020] Preferably according to the present invention, the magnetic material is any one of yttrium iron garnet, iron oxide, permalloy, and cobalt zirconium alloy; the magnetic material generates ferromagnetic resonance under microwave driving.

[0021] Further preferably, the bias magnetic field is any one of a neodymium iron boron magnet, a ferrite magnet, and an electromagnetic coil.

[0022] Preferably according to the present invention, the signal readout system is any one of a vector network analyzer, a signal analyzer, a HackRFOne, an oscilloscope, and a nanovoltmeter.

[0023] Preferably according to the present invention, the signal amplifier is a low-noise high electron mobility transistor (HEMTs), and both the gain G1 and the gain G2 are 0 - 25 dB;

[0024] Further preferably, both the gain G1 and the gain G2 are 25 dB.

[0025] An alternating magnetic field sensitive detection method based on sideband regulation of a resonator-magnon coupling system is realized by the above-mentioned alternating magnetic field sensitive detection device, and includes:

[0026] Insert a magnon, that is, a YIG sphere, into the superconducting resonator to form a resonator-magnon coupling system. A microwave source generates monochromatic microwaves to drive the resonator-magnon coupling system. The microwaves radiated by the resonator-magnon coupling system are filtered by a filter, and then amplified by two signal amplifiers for the signal to be measured. After being rectified by a rectifying diode, the voltage signal measured by a voltmeter reflects the magnitude of the alternating magnetic field.

[0027] Preferably according to the present invention, a yttrium iron garnet YIG sphere is placed at the center of a yttrium barium copper oxide superconducting resonator to form a resonator-magnon coupling system; the bias magnetic field adjusts the Larmor frequency of the electrons in the yttrium iron garnet YIG sphere to the cavity mode frequency and couples the magnon mode with the resonator mode;

[0028] Further preferably, when the magnon is coupled with the resonator, the cavity mode splits into two hybrid modes;

[0029] A permanent magnet provides an external magnetic field B. When an alternating magnetic field b1 parallel to the external magnetic field B provided by an alternating signal is added and a monochromatic microwave is applied to any one of the two hybrid modes by the driving microwave, the alternating magnetic field b1 with a frequency of ω b will generate a frequency modulation for ω i , i = 1, 2. Sidebands are generated at the frequency ω i +nω b ; only the sidebands that satisfy the relationship ω1 + nω b =ω2 appear, and other sidebands are suppressed; for a weak magnetic field, only the sideband component corresponding to n = 1 has a significant amplitude, and for the frequency ω b =2g 21The detection of the alternating magnetic field is relatively sensitive. Subsequently, the filter filters out the microwaves other than the signal to be measured. After amplification and rectification, finally, using the relationship that the intensity of the sideband signal is positively correlated with the magnitude of the alternating magnetic field, the magnitude of the alternating magnetic field is reflected by the voltage signal measured by the voltmeter.

[0030] The beneficial effects of the present invention are as follows:

[0031] 1. Ultra-high sensitivity: The present invention realizes the amplification of weak alternating magnetic field signals. Through the suppression of other sideband signals by the resonator-magnon coupling system and the filter, the magnetometer realizes the sensitive detection of the alternating magnetic field, and the detection sensitivity reaches 5 pT / √Hz.

[0032] 2. Low cost: The superconducting resonator, filter, signal amplifier, and magnetic material used in the present invention all have mature commercial products and do not require additional research and development.

[0033] 3. Easy integration: The superconducting resonator and filter used in the present invention can be planar microwave devices. These planar structures can adopt micro-nano processing technology to reduce the size to the micron size. In addition, since the device sensitivity does not depend on its size, smaller PMHS can be designed.

[0034] 4. Simple structure: The present invention does not require a complex optical path, and the detection signal can be read out electrically. In addition, the present invention can work at (room temperature) and does not require additional heating or cooling devices. Brief Description of the Drawings

[0035] Figure 1 is a schematic structural diagram of the magnetic field sensitive detection device based on the superconducting resonator-magnon coupling system of the present invention;

[0036] Figure 2 is a schematic diagram of the transmission of the resonator-magnon coupling system and the filter varying with frequency;

[0037] Figure 3 is a schematic diagram of the signal spectrum under alternating magnetic fields of different magnitudes;

[0038] Figure 4 is a schematic diagram of the change of the voltage signal with alternating magnetic fields of different magnitudes. Detailed Embodiments

[0039] The present invention will be further limited below in conjunction with the drawings of the specification and embodiments, but not limited thereto.

[0040] Embodiment 1

[0041] A sensitive detection device for alternating magnetic fields based on sideband regulation of a resonator-magnon coupling system, as Figure 1 shown, includes:

[0042] A microwave source, a superconducting resonator, a YIG sphere, a filter, two signal amplifiers, a rectifying diode, a permanent magnet, and a signal readout system;

[0043] The resonator - magnon coupling system includes a superconducting resonator and a YIG sphere, and the YIG sphere is placed at the center of the superconducting resonator; since both generate radiated microwaves, there is an interaction between the YIG sphere and the superconducting resonator. At this time, there are two eigenmodes in the system, and the variation of their frequencies with the magnetic field shows an anti - crossing curve.

[0044] The microwave source generates monochromatic microwaves to drive the superconducting resonator and the YIG sphere. After being modulated by the alternating magnetic field to be measured, the output signal passes through the filter, two signal amplifiers, and a rectifying diode in sequence, and finally is measured by a voltmeter;

[0045] The superconducting resonator converts the magnitude of the alternating magnetic field into the intensity of the sideband signal through the coupling with the magnetic material, and plays a role in information conversion in the whole measuring device;

[0046] The magnon, that is, the YIG sphere, is used to sense the alternating magnetic field. When the alternating magnetic field acts on the YIG sphere, through the coupling effect, the microwave - driven resonator - magnon coupling system generates sideband signals. By measuring the intensity of the sideband signals, the magnitude of the alternating magnetic field can be deduced;

[0047] The filter filters out microwaves other than the signal to be measured and transmits monochromatic microwaves;

[0048] The signal amplifier amplifies the output signal to improve the signal - to - noise ratio; the signal reflected from the cavity is filtered and amplified before being read out. The filtering removes the residual driving signal to avoid amplifier saturation.

[0049] The rectifying diode rectifies the output signal, and the voltage signal measured by the voltmeter reflects the magnitude of the alternating magnetic field;

[0050] [[ID=2s]]The permanent magnet provides a stable bias magnetic field for the YIG sphere to make the YIG sphere generate precession at a specific frequency;

[0051] The signal readout system is used to detect the intensity of the sideband signal.

[0052] The magnetic - field sensitive detection device of the present invention utilizes a resonator - magnon coupling system. Based on the phase modulation of the resonator - magnon resonance excited by the alternating magnetic field, by detecting the intensity of the output sideband signal, a weak magnetic field can be measured.

[0053] Embodiment 2

[0054] A sensitive detection device for alternating magnetic field based on sideband regulation of a resonator - magnon coupling system according to Embodiment 1, wherein the difference lies in:

[0055] The superconducting resonator is any one of a microstrip line resonator, a split ring resonator, a dielectric resonator, and a microwave cavity.

[0056] The magnetic material is any one of yttrium iron garnet, iron oxide, permalloy, and cobalt zirconium alloy; the magnetic material generates ferromagnetic resonance under microwave excitation.

[0057] The bias magnetic field is any one of a neodymium iron boron magnet, a ferrite magnet, and an electromagnetic coil.

[0058] The signal readout system is any one of a vector network analyzer, a signal analyzer, a HackRF One, an oscilloscope, and a nanovoltmeter.

[0059] The signal amplifier is a low-noise high electron mobility transistor (HEMTs), and both the gain G1 and the gain G2 are 0 - 25 dB;

[0060] Both the gain G1 and the gain G2 are 25 dB.

[0061] Figure 2 It is a schematic diagram of the transmission of the cavity magnon coupling system and the filter varying with frequency; the driving signal passes through the coupling system, and due to the modulation of the alternating magnetic field parallel to the external magnetic field, a sideband signal is obtained at ω2. Subsequently, it passes through a cylindrical resonator acting as a filter, and its transmission is as shown in Figure 2 the blue part of (a) in Figure 2 in (b), the abscissa is the frequency of the alternating magnetic field, and the ordinate is the voltage signal. Figure 2 In (a), it is the variation of the transmission voltage of the resonator magnon coupling system with frequency and the variation of the filter transmission voltage with frequency. Figure 2 In (b), with the magnitude of the alternating magnetic field fixed, the variation of the detected voltage magnitude with the frequency of the alternating magnetic field is detected.

[0062] [[ID=3,1]]There is a cavity mode at ω2, while there is no mode at ω1, and microwaves outside the signal ω2 to be measured can be filtered out. Subsequently, the output signal is amplified by two low-noise amplifiers with a gain of 25 dB to improve the signal-to-noise ratio. Finally, it is rectified by a diode, and the voltage signal as shown in Figure 2 in (b) is measured by a voltmeter to reflect the magnitude of the alternating magnetic field.

[0063] The embodiment detects the alternating magnetic field component of 200 MHz. As shown in Figure 3 , the alternating magnetic fields of 283 nT, 502 nT, 913 nT, and 1607 T are detected respectively. Figure 3 In (a), it is a schematic diagram of the 283 nT alternating magnetic field.Figure 3 Figure (b) is a schematic diagram of an alternating magnetic field of 502 nT. Figure 3 Figure (c) is a schematic diagram of an alternating magnetic field of 913 nT. Figure 3 Figure (d) is a schematic diagram of an alternating magnetic field of 1607 T.

[0064] Figure 4 It is a schematic diagram of the change of an alternating magnetic field with different magnitudes of voltage signals.

[0065] Example 3

[0066] A sensitive detection method for alternating magnetic fields based on sideband control of a resonator-magnon coupling system is realized by the alternating magnetic field sensitive detection device described in Example 1 or 2, and includes:

[0067] Insert a magnon, i.e., a YIG sphere, into the superconducting resonator to form a resonator-magnon coupling system. The microwave source generates monochromatic microwaves to drive the resonator-magnon coupling system. The microwaves radiated by the resonator-magnon coupling system are filtered by a filter, and then amplified by two signal amplifiers for the signal to be measured. After being rectified by a rectifier diode, the voltage signal measured by a voltmeter is used to reflect the magnitude of the alternating magnetic field.

[0068] Place a yttrium iron garnet (YIG) sphere at the center of the yttrium barium copper oxide superconducting resonator to form a resonator-magnon coupling system; YIG has an extremely high electron spin density, which has reached 2×10 28 spin / m 3 at room temperature, and the linewidth is as narrow as 1 MHz. The bias magnetic field adjusts the Larmor frequency of the electrons in the yttrium iron garnet (YIG) sphere to the cavity mode frequency and couples the magnon mode with the resonator mode;

[0069] When the magnon is coupled with the resonator, the cavity mode splits into two hybrid modes; the resulting system can be described by quasiparticles of cavity magnon polarons (CMPs), and its dispersion relation is an anti-crossing curve.

[0070] The permanent magnet provides an external magnetic field B. When an alternating magnetic field b1 parallel to the external magnetic field B provided by an alternating signal is applied, and monochromatic microwaves are applied to any one of the two hybrid modes (such as frequency ω i ) by the driving microwave, the alternating magnetic field b1 with frequency ω b will generate frequency modulation for ω i , i = 1, 2, and sidebands will be generated at the frequency ω i +nω b ; however, since the resonator-magnon system has only two modes, only when ω1 + nω bThe sidebands with the n = ω2 relationship appear, and other sidebands are suppressed; for weak magnetic fields, only the sideband component corresponding to n = 1 has a significant amplitude, and it is sensitive to the detection of the alternating magnetic field with frequency ω b = 2g 21 and is more sensitive to the detection of the alternating magnetic field. Subsequently, the filter filters out the microwaves other than the signal to be measured. After amplification and rectification, finally, using the relationship that the intensity of the sideband signal is positively correlated with the magnitude of the alternating magnetic field, the magnitude of the alternating magnetic field is reflected by the voltage signal measured by the voltmeter. By detecting the power at ω2, the measured value of the alternating magnetic field is obtained. The relationship between the measured voltage U and the magnitude of the alternating magnetic field B is U = 0.058·B - 13.3.

Claims

1. An alternating magnetic field sensitive detection device based on sideband modulation of a resonator-magnon coupling system, characterized in that, Comprising: A microwave source, a superconducting resonator, a YIG sphere, a filter, two signal amplifiers, a rectifying diode, a permanent magnet, and a signal readout system; The resonator-magnon coupling system includes a superconducting resonator and a YIG sphere, and the YIG sphere is placed at the center of the superconducting resonator; the microwave source generates monochromatic microwaves to drive the superconducting resonator and the YIG sphere. After being modulated by the alternating magnetic field to be measured, the output signal sequentially passes through the filter, two signal amplifiers, and a rectifying diode, and finally is measured by a voltmeter; The superconducting resonator converts the magnitude of the alternating magnetic field into the intensity of the sideband signal through the coupling with the magnetic material; The magnon, that is, the YIG sphere, is used to sense the alternating magnetic field. When the alternating magnetic field acts on the YIG sphere, through the coupling effect, the resonator-magnon coupling system driven by microwaves generates sideband signals. By measuring the intensity of the sideband signals, the magnitude of the alternating magnetic field is deduced; The filter filters out microwaves other than the signal to be measured and transmits monochromatic microwaves; The signal amplifier amplifies the output signal to improve the signal-to-noise ratio; The rectifying diode rectifies the output signal, and the voltage signal measured by the voltmeter reflects the magnitude of the alternating magnetic field; The permanent magnet provides a bias magnetic field for the YIG sphere to cause precession of the frequency of the YIG sphere; The signal readout system is used to detect the intensity of the sideband signals.

2. The alternating magnetic field sensitive detection device based on sideband regulation of a resonator-magnon coupling system according to claim 1, wherein The superconducting resonator is any one of a microstrip line resonator, an open resonator, a dielectric resonator, and a microwave resonator.

3. The alternating magnetic field sensitive detection device based on sideband regulation of a resonator-magnon coupling system according to claim 1, characterized in that, The magnetic material is any one of yttrium iron garnet, iron oxide, permalloy, and cobalt zirconium alloy; the magnetic material generates ferromagnetic resonance under microwave drive.

4. The alternating magnetic field sensitive detection device based on sideband regulation of a resonator-magnon coupling system according to claim 1, characterized in that, The bias magnetic field is any one of a neodymium iron boron magnet, a ferrite magnet, and an electromagnetic coil.

5. An alternating magnetic field sensitive detection device based on sideband regulation of a resonator-magnon coupling system according to claim 1, characterized in that, The signal readout system is any one of a vector network analyzer, a signal analyzer, a HackRFOne, an oscilloscope, and a nanovoltmeter.

6. An alternating magnetic field sensitive detection device based on sideband regulation of a resonator-magnon coupling system according to claim 1, characterized in that The signal amplifier is a low-noise high electron mobility transistor, and both the gain G1 and the gain G2 are 0 - 25 dB.

7. An alternating magnetic field sensitive detection device based on sideband regulation of a resonator-magnon coupling system according to claim 1, characterized in that, Both the gain G1 and the gain G2 are 25 dB.

8. A method for sensitive detection of alternating magnetic fields based on sideband modulation of a resonator-magnon coupling system, implemented by the alternating magnetic field sensitive detection device according to any one of claims 1-7, characterized in that Comprising: Inserting a magnon, that is, a YIG sphere, into the superconducting resonator to form a resonator-magnon coupling system. The microwave source generates monochromatic microwaves to drive the resonator-magnon coupling system. The microwaves radiated by the resonator-magnon coupling system are filtered by the filter, and then the two signal amplifiers amplify the signal to be measured. After being rectified by the rectifying diode, the voltage signal measured by the voltmeter reflects the magnitude of the alternating magnetic field.

9. A method for sensitive detection of alternating magnetic fields based on sideband modulation of a resonator-magnon coupling system, as claimed in claim 8, wherein Placing a yttrium iron garnet YIG sphere at the center of the yttrium barium copper oxide superconducting resonator to form a resonator-magnon coupling system; the bias magnetic field adjusts the Larmor frequency of the electrons in the yttrium iron garnet YIG sphere to the cavity mode frequency and couples the magnon mode with the resonator mode.

10. According to the method for sensitive detection of an alternating magnetic field based on sideband regulation of a resonator-magnon coupling system as claimed in claim 8 or 9, when the magnon and the resonator are coupled, the cavity mode splits into two hybrid modes; A permanent magnet provides an external magnetic field B. When an alternating magnetic field b1 parallel to the external magnetic field B provided by an alternating signal is added and a monochromatic microwave is applied to any one of the two hybrid modes by driving the microwave, the frequency is ω b of the alternating magnetic field b1 will generate a frequency modulation of ω i , i = 1, 2. At the frequency ω i +nω b sidebands are generated; only the sidebands that satisfy the relationship ω1 + nω b = ω2 appear, and other sidebands are suppressed; for weak magnetic fields, only the sideband component corresponding to n = 1 has a significant amplitude. For the alternating magnetic field with ω b = 2g 21 is more sensitive to detection. Subsequently, the filter filters out the microwaves other than the signal to be measured. After amplification and rectification, finally, using the relationship that the intensity of the sideband signal is positively correlated with the magnitude of the alternating magnetic field, the magnitude of the alternating magnetic field is reflected by the voltage signal measured by the voltmeter.

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