Low-power-consumption SERF atom spinning precession magnetic field regulation and control method and device

Abstract

The invention discloses a low-power-consumption SERF atom spin precession magnetic field regulation and control method and device, and aims at the high-energy-efficiency spin regulation and control requirement of SERF atoms, the low-power-consumption SERF atom spin precession regulation and control method is introduced, a low-power-consumption magnetic field modulation module design method is utilized, and the magnetic field signal detection sensitivity of the SERF atoms is improved. And the magnetic field modulation energy consumption in the SERF atom spin precession signal detection process is reduced. And based on the SERF atom precession detection module, precise magnetic field regulation and control detection of SERF atom spin precession is realized, and the modulation power consumption of the SERF atom spin precession magnetic field is reduced. The magnetic field regulation and control method and device which are high in energy efficiency, low in power consumption, convenient to use, high in precision and high in universality are provided for SERF atom spin precession signal detection research.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of atomic magnetometer and atomic signal detection, and particularly relates to a low-power SERF atomic spin precession magnetic field regulation method and device, and belongs to the technical field of quantum precision measurement and magnetic field sensor optimization. BACKGROUND

[0002] With the increasing demand for ultra-weak magnetic field detection, spin-exchange relaxation-free (SERF) atomic magnetometers have been widely used in geophysical exploration, bio-magnetic imaging (such as magnetoencephalography MEG, magnetocardiography MCG) and basic physics experiments (such as dark matter detection, quantum gravity measurement) due to their high sensitivity and wide frequency response in the field of ultra-weak magnetic field detection. This type of magnetometer realizes the excitation and detection of the spin polarization state of alkali metal atoms (such as potassium, rubidium, etc.) by optical means, and then measures the Larmor precession frequency to infer the external magnetic field strength.

[0003] In the SERF working mode, the atoms are heated to a certain temperature in a near-zero magnetic field environment to obtain a high enough atomic density, so that the spin exchange collision frequency is much higher than the Larmor precession frequency, thereby suppressing the transverse spin relaxation effect. At this time, the sensitivity of the magnetic field measurement is mainly affected by the atomic spin polarization degree and the transverse relaxation time (T2). Due to this mechanism, the current SERF-based atomic magnetometer can achieve a detection accuracy better than 10-12 T, far exceeding the level that can be achieved by traditional fluxgate and superconducting quantum interference devices (SQUID).

[0004] However, in order to achieve the spin-exchange relaxation-free state, the atomic vapor cell must be heated to increase the density of alkali metal atoms. The most commonly used heating method is resistance heating, that is, by arranging resistance wires on a heating cavity made of non-magnetic material and applying alternating current to achieve constant temperature control. Although this method has a simple structure and stable temperature control, it inevitably introduces heat-induced magnetic noise related to the heating current, which interferes with high-sensitivity magnetic field measurement.

[0005] Especially noteworthy is that different current waveforms (such as square wave, sine wave, and triangular wave) have different high harmonic components in the frequency spectrum, which directly affect the spin polarization process of the atoms and thus affect the final sensitivity of the magnetometer. At present, 50% duty cycle square wave is commonly used as the heating current waveform in engineering, although it is simple to control, but due to the rich high-frequency harmonic components, it results in stronger magnetic noise and more complex coupling. At the same time, in order to minimize this interference, it is usually necessary to increase the current frequency (often in the range of several kHz to several tens of kHz), which not only significantly increases the power consumption, but also increases the design difficulty of the heating circuit and shielding system.​

[0006] Therefore, how to reduce system energy consumption, reduce magnetic noise coupling and improve magnetic field measurement sensitivity under the premise of ensuring heating effect and atomic polarization efficiency has become a key problem in the optimization design of the current SERF atomic magnetometer system. More accurate regulation of the SERF atomic spin precession process, especially in the selection of modulated magnetic field waveform and the optimization of heating strategy, has become a technical bottleneck that needs to be broken through in the field. SUMMARY

[0007] The present application aims at the problems of high power consumption and great influence on instrument sensitivity of the existing SERF atomic magnetic field modulation, and provides a low-power SERF atomic spin precession magnetic field regulation method and device, which can optimize the waveform control of the heating magnetic field, suppress the transverse relaxation effect, thereby realizing low-power operation and improving system stability and measurement accuracy without reducing the magnetic sensing sensitivity. The device has the advantages of stable atomic precession response, convenient control, low instrument modification cost, etc.

[0008] To achieve the above object, the present application realizes the following technical scheme: A low-power SERF atomic spin precession magnetic field regulation method, comprising the following steps: S1: input the number of iterations n required for iteration optimization, which is used to control the maximum number of iteration rounds of magnetic field waveform optimization in the SERF atomic precession regulation process; S2: initialize the SERF atomic chamber and the SERF atomic precession detection module to ensure normal operation of the spin signal acquisition system; S3: use the magnetic field waveform signal output device to input a preset magnetic field waveform to the magnetic field modulation coil to start regulating the SERF atomic spin precession in the SERF atomic chamber, and the magnetic field waveform can be sine, square wave or other forms; S4: real-time collect the atomic spin precession signal through the SERF atomic precession detection module to obtain key parameters such as amplitude, frequency and phase of the signal; S5: analyze and evaluate the collected atomic spin precession signal, including calculating signal-to-noise ratio (SNR), spectral characteristics and regulation response speed, etc., to determine whether the current magnetic field waveform regulation effect meets the requirements; S6: compare the power consumption corresponding to the current input magnetic field waveform with the recorded minimum power consumption modulation waveform, if the current waveform power consumption is lower, go to step S7, otherwise jump to step S8; S7: record the current waveform as the latest minimum power consumption modulation waveform, and update the optimal magnetic field waveform parameters in the original record; S8: judge whether the current iteration number reaches the input set iteration total number n, if not, return to step S3 to input the next group of magnetic field waveform for regulation test; if the maximum iteration number is reached, enter step S9; S9: output the recorded minimum power consumption magnetic field modulation waveform parameters, including waveform type, amplitude, frequency, phase and other information, as the final regulation result of the system optimization.

[0009] As preferred, the magnetic field waveform is square wave, sine wave or triangular wave.

[0010] The application also provides a low-power SERF atomic spin precession magnetic field regulation device, comprising a low-power magnetic field modulation module, a SERF atomic precession detection module and a SERF atomic chamber.

[0011] As preferred, the low-power magnetic field modulation module comprises a magnetic field modulation coil and a magnetic field waveform signal output device; the magnetic field modulation coil is used to generate a modulation magnetic field for regulating the SERF atomic spin precession in the SERF atomic chamber; and the magnetic field waveform signal output device is used to provide various magnetic field waveform sources for the SERF atomic spin precession signal in the SERF atomic chamber.

[0012] As preferred, the SERF atomic precession detection module comprises a SERF atomic precession state detection light path and an atomic state detector; the SERF atomic precession state detection light path is used to interact with the SERF atomic spin in the SERF atomic chamber, so that the SERF atomic spin phase in the SERF atomic chamber is superimposed on the SERF atomic precession state detection light path phase and is vertically input to the surface of the atomic state detector for detection; and the atomic state detector judges the SERF atomic spin precession state in the SERF atomic chamber by detecting the light polarization change.

[0013] As preferred, the non-magnetic connecting wire is used to connect the magnetic field modulation coil and the magnetic field waveform signal output device, so as to ensure that the magnetic field waveform is not distorted.

[0014] As preferred, the SERF atomic chamber is located at the center position of the magnetic field modulation coil.

[0015] As preferred, the non-magnetic connecting wire is made of silver-plated enameled copper wire material and adopts double-twisted and symmetrical structure, and is wrapped with an electromagnetic shielding material, so that the magnetic signal is negligible.

[0016] The application has the following beneficial effects: (1) The application comprehensively considers the functions and working requirements of various devices, and under the same power condition, the same or even higher sensitivity of the traditional high-power waveform can be achieved by optimizing the magnetic field waveform instead of improving the power.

[0017] (2) By using a low-power magnetic field modulation control method, the low-power precision control of the spin precession of SERF atoms can be realized, which greatly improves the energy efficiency of SERF atom magnetic field control, reduces the dependence on strong magnetic field equipment, and greatly reduces the life loss during magnetic field control.

[0018] (3) This invention takes into account the device integration performance and can be combined with micro-nano fabrication technology to achieve chip-level packaging, providing a new path for low-power quantum devices.

[0019] (4) The present invention can realize active compensation coil magnetic shielding of SERF atoms, and by continuously reducing the magnetic field modulation power consumption, the magnetic field resonance zero point of SERF atoms can be found.

[0020] This invention can be widely used in applications such as high-sensitivity geomagnetic detection and medical magnetic physiological imaging, and is of great significance for reducing system power consumption and improving portability. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall experimental setup for a low-power SERF atom spin precession magnetic field control method and device according to the present invention. Figure 2 This is a schematic diagram of a low-power SERF atom spin precession magnetic field control method according to the present invention; Figure 3 This is a flowchart of an atomic spin precession control method and device for low-power SERF atomic spin precession magnetic field control according to the present invention. Figure 4 This is a graph showing the test results of potassium atom precession response to different magnetic field waveform modulations of a low-power SERF atom spin precession magnetic field control method and device of the present invention. In the figure, there is a SERF atom chamber 3, a magnetic field modulation coil 11, a non-magnetic connecting line 12, a magnetic field waveform signal output device 13, a SERF atom precession state detection optical path 21, and an atom state detector 22. Detailed Implementation

[0022] The present invention will become clearer from the following detailed description with reference to the accompanying drawings and preferred embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of the invention.

[0023] like Figure 1 As shown, a low-power SERF atom spin precession magnetic field control device of the present invention includes a low-power magnetic field modulation module, a SERF atom precession detection module, a SERF atom chamber 3, a magnetic field modulation coil 11, a non-magnetic connecting line 12, a magnetic field waveform signal output device 13, a SERF atom precession state detection optical path 21, and an atom state detector 22.

[0024] The low-power magnetic field modulation module includes a magnetic field modulation coil 11, a non-magnetic connection line 12, and a magnetic field waveform signal output device 13. The magnetic field modulation coil 11 is used to generate a modulation magnetic field for regulating the spin precession of the SERF atoms in the SERF atom chamber 3. The non-magnetic connection line 12 is used to connect the magnetic field modulation coil 11 and the magnetic field waveform signal output device 13, ensuring that the magnetic field waveform is not distorted. The magnetic field waveform signal output device 13 is used to provide various magnetic field waveform sources for the spin precession signal of the SERF atoms in the SERF atom chamber 3.

[0025] The SERF atom precession detection module includes a SERF atom precession state detection light path 21 and an atomic state detector 22. The SERF atom precession state detection light path 21 is used to interact with the spin of the SERF atoms in the SERF atom chamber 3, so that the spin phase of the SERF atoms in the SERF atom chamber 3 is superimposed on the phase of the SERF atom precession state detection light path 21, and is vertically input to the surface of the atomic state detector 22 for detection. The SERF atom precession state detection light path 21 is generated by a laser. The atomic state detector 22 judges the spin precession state of the SERF atoms in the SERF atom chamber 3 by detecting the change of light polarization.

[0026] Preferably, the SERF atom chamber 3 is located at the center position of the magnetic field modulation coil 11.

[0027] Embodiment 1: This embodiment describes a low-power SERF atom spin precession magnetic field regulation method and device and method for a potassium atom-based SERF quantum precision magnetic measurement device, which regulates the SERF state potassium atoms to a certain spin precession state and reduces the power consumption of magnetic field regulation. The low-power SERF atom spin precession magnetic field regulation method and device and method specifically include a low-power magnetic field modulation module, a SERF atom precession detection module, a SERF atom chamber 3, a magnetic field modulation coil 11, a non-magnetic connection line 12, a magnetic field waveform signal output device 13, a SERF atom precession state detection light path 21, and an atomic state detector 22.

[0028] In specific implementation, the low-power SERF atom spin precession magnetic field regulation method includes the following steps in the specific operation process: Step 1: input the number of iterations required for optimization 3, which is used to control the maximum number of iteration rounds for optimizing the magnetic field waveform in the SERF atom precession regulation process; Step 2: initialize the SERF atomic chamber 3, including heating the potassium atoms to 200℃, turning on the 770.108 nm pump light source, and initializing the SERF atomic precession detection module, including the potassium atom precession state detection 770.486 nm light path, the atomic state detection photodiode, and ensuring the normal operation of the spin signal acquisition system; Step 3: use the magnetic field waveform signal output device 13 to input a preset magnetic field waveform to the magnetic field modulation coil 11 to start regulating the spin precession of the SERF state potassium atoms. The magnetic field waveform can be a sine wave, a 50% duty cycle square wave, or a triangular wave. Step 4: Real-time acquisition of atomic spin precession signals by the SERF state potassium atom precession detection module to obtain key parameters such as amplitude, frequency, and phase of the potassium atom spin precession signal. Step 5: Analyze and evaluate the SERF state potassium atom spin precession signal collected by the atomic state detector 22, including signal-to-noise ratio, atomic precession response spectrum characteristics, and control response speed, to determine whether the current magnetic field waveform control effect meets the requirements. Step 6: Compare the power consumption of the current input magnetic field waveform with the recorded minimum power consumption modulation waveform. If the current waveform has lower power consumption, go to step 7, otherwise jump to step 8. Step 7: Record the current waveform as the latest minimum power consumption modulation waveform and update the optimal magnetic field waveform parameters in the original record. Step 8: Determine whether the current iteration number has reached the input set iteration total number 3. If not, return to step 3 to input the next set of magnetic field waveforms for control testing. If the maximum iteration number 3 has been reached, go to step 9. Step 9: Output the recorded minimum power consumption magnetic field modulation waveform parameters, including waveform type, amplitude, frequency, phase, and other information, as the final magnetic field control result of the optimized potassium atom spin precession. In one embodiment, the magnetic field waveform signal output device 13 connects the magnetic field modulation coil 11 through the non-magnetic connection line 12, and sequentially applies a sine wave modulation magnetic field, a 50% duty cycle square wave modulation magnetic field, and a triangular wave modulation magnetic field to make the potassium atoms in the SERF atomic chamber 3 reach the same spin precession state, as shown in Figure 4 The power consumption of different modulation waveforms is calculated and compared, and the SERF state potassium atom spin precession magnetic field control scheme with the lowest power consumption is finally obtained.

[0029] Example 2:

[0030] The embodiment illustrates that the low-power SERF atomic spin precession magnetic field regulation method and device and method are configured to the SERF quantum precision magnetic shielding device based on rubidium atoms, the SERF state rubidium atoms are regulated to a determined spin precession state, and the power consumption of the magnetic field regulation is reduced. The low-power SERF atomic spin precession magnetic field regulation method and device and method specifically include a low-power magnetic field modulation module, a SERF rubidium atom precession detection module, a SERF rubidium atom chamber 3, a magnetic field modulation coil 11, a non-magnetic connection line 12, a magnetic field waveform signal output device 13, a SERF rubidium atom precession state detection optical path 21, and a rubidium atom state detector 22.

[0031] In specific implementation, the low-power SERF atomic spin precession magnetic field regulation method includes the following steps in the specific operation process: Step 1: input the number of iterations required for optimization 3, which is used to control the maximum number of iteration rounds of the magnetic field waveform optimization in the SERF rubidium atom precession regulation process; Step 2: initialize the SERF rubidium atom chamber 3, including heating the potassium atoms to 180℃, turning on the 795 nm pump light source, and the like, and initialize the SERF rubidium atom precession detection module, including the potassium atom precession state detection 795.384 nm optical path, the rubidium atom state detection photodiode, and ensure the normal operation of the spin signal acquisition system; Step 3: input the preset magnetic field waveform to the magnetic field modulation coil 11 by using the magnetic field waveform signal output device 13, and start regulating the spin precession of the SERF state rubidium atoms, the magnetic field waveform can be a sine wave, a 50% duty cycle square wave, or a triangular wave; Step 4: collect the atomic spin precession signals in real time by using the SERF state rubidium atom precession detection module, and obtain the amplitude, frequency, phase, and the like of the rubidium atom spin precession signals; Step 5: analyze and evaluate the SERF state rubidium atom spin precession signals collected by the atomic state detector 22, including the signal-to-noise ratio, the atomic precession response spectrum characteristics, and the regulation response speed, and determine whether the current magnetic field waveform regulation effect meets the requirements; Step 6: compare the power consumption corresponding to the current input magnetic field waveform with the recorded minimum power consumption modulation waveform, if the current waveform power consumption is lower, go to step 7, otherwise jump to step 8; Step 7: record the current waveform as the latest minimum power consumption modulation waveform, and update the optimal magnetic field waveform parameters in the original record; Step 8: determine whether the current iteration number reaches the input set iteration total number 3, if not, return to step 3 to input the next group of magnetic field waveforms for regulation test; if the maximum iteration number 3 is reached, go to step 9; Step 9: output the minimum power consumption magnetic field modulation waveform parameters of the record, including waveform type, amplitude, frequency, phase and other information, as the final rubidium atom spin precession magnetic field regulation result after system optimization; In specific implementation, the minimum value of the SERF rubidium atom spin precession magnetic field regulation is the optimal value of the shielding performance of the SERF quantum precision magnetic shielding device based on the rubidium atom.

[0032] Those skilled in the art can understand that the above description is only a preferred example of the application and is not used to limit the application, although the application has been described in detail with reference to the foregoing examples, those skilled in the art can still modify the technical solutions recorded in the foregoing examples or make equivalent replacement for part of the technical features. Any modification, equivalent replacement and the like within the spirit and principles of the application shall be included in the protection scope of the application.

Claims

1. A low-power method for controlling the spin precession magnetic field of SERF atoms, characterized in that, Includes the following steps: S1: Input parameter n, which is the number of iterations required for optimization; S2: Initialize the SERF atom chamber and SERF atom precession detection module to ensure the normal operation of the spin signal acquisition system; S3: Using the magnetic field waveform signal output device, a preset magnetic field waveform is input to the magnetic field modulation coil to start regulating the spin precession of SERF atoms in the SERF atom chamber; S4: The SERF atomic precession detection module is used to acquire atomic spin precession signals in real time, obtaining the amplitude, frequency, and phase parameters of the signals; S5: Analyze and evaluate the collected atomic spin precession signals, including calculating the signal-to-noise ratio, spectral characteristics, and control response speed indicators, and determine whether the current magnetic field waveform control effect meets the requirements; S6: Compare the power consumption corresponding to the current input magnetic field waveform with the recorded minimum power consumption modulation waveform. If the power consumption of the current waveform is lower, proceed to step S7; otherwise, skip to step S8. S7: Record the current waveform as the latest minimum power consumption modulation waveform and update the optimal magnetic field waveform parameters in the original record; S8: Determine whether the current iteration count has reached the input set total number of iterations n. If not, return to step S3 to re-enter the next set of magnetic field waveforms for adjustment testing; if the maximum number of iterations has been reached, proceed to step S9. S9: Output the minimum power consumption magnetic field modulation waveform parameters, including waveform type, amplitude, frequency, and phase information, as the final control result.

2. The low-power SERF atom spin precession magnetic field control method according to claim 1, characterized in that, The magnetic field waveform is a square wave, a sine wave, or a triangular wave.

3. A low-power SERF atomic spin precession magnetic field control device, characterized in that, This method is used to implement a low-power SERF atom spin precession magnetic field control method as described in any one of claims 1-2. The device includes a low-power magnetic field modulation module, a SERF atomic precession detection module, and a SERF atomic chamber (3); the low-power magnetic field modulation module includes a magnetic field modulation coil (11) and a magnetic field waveform signal output device (13); the SERF atomic precession detection module includes a SERF atomic precession state detection optical path (21) and an atomic state detector (22).

4. The low-power SERF atomic spin precession magnetic field control device according to claim 3, characterized in that, The magnetic field modulation coil (11) is used to generate a modulation magnetic field that regulates the spin precession of SERF atoms in the SERF atom chamber (3); the magnetic field waveform signal output device (13) is used to input a preset magnetic field waveform to the magnetic field modulation coil (11) to provide various magnetic field waveform sources for the spin precession signal of SERF atoms in the SERF atom chamber (3).

5. A low-power SERF atomic spin precession magnetic field control device according to claim 3, characterized in that, The SERF atom precession state detection optical path (21) is used to interact with the SERF atom spins in the SERF atom chamber (3), so that the phase of the SERF atom spins in the SERF atom chamber (3) is superimposed on the phase of the SERF atom precession state detection optical path (21), and is vertically input to the surface of the atom state detector (22) for detection; the atom state detector (22) determines the SERF atom spin precession state in the SERF atom chamber (3) by detecting the change in light polarization.

6. A low-power SERF atomic spin precession magnetic field control device according to claim 3, characterized in that, The low-power magnetic field modulation module also includes a non-magnetic connecting wire (12) for connecting the magnetic field modulation coil (11) and the magnetic field waveform signal output device (13) to ensure that the magnetic field waveform is not distorted.

7. A low-power SERF atomic spin precession magnetic field control device according to claim 3, characterized in that, The SERF atomic chamber (3) is located at the center of the magnetic field modulation coil (11).

8. A low-power SERF atomic spin precession magnetic field control device according to claim 6, characterized in that, The non-magnetic connecting wire (12) is made of silver-plated enameled copper wire and has a twisted and symmetrical structure, with an outer layer of electromagnetic shielding material.

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