An atomic magnetometer device and method based on multiple physical reference channels

Abstract

A kind of atomic magnetometer device and method based on multiple physical reference channels, by synchronously sensing the optical state, thermal state and magnetic field output state of atomic magnetometer, the magnetic field reading drift caused by environmental disturbance is compensated online.This application sets up pumping light regulation and reference collection module, probe light regulation and reference collection module and temperature reference collection module, through the time delay correction of reference channel and the real-time update of compensation parameter, the protection of effective weak magnetic signal under real dynamic magnetic field condition is realized.On the basis of not changing the original atomic magnetometer measurement principle and polarization differential detection mode, this scheme can weaken the reading drift caused by thermal disturbance, light intensity fluctuation and optical path state change, reduce the false compensation to real dynamic weak magnetic signal, improve the measurement stability, environmental adaptability and dynamic waveform retention capability, and is easy to integrate and apply in existing atomic magnetometer platform.

Description

Technical Field

[0001] This invention relates to an atomic magnetometer device and method based on multiple physical reference channels, belonging to the fields of atomic magnetometer, quantum precision measurement and weak magnetic field measurement technology. Background Technology

[0002] Atomic magnetometers measure weak magnetic fields by detecting the response of alkali metal atoms to an external magnetic field. They offer advantages such as high sensitivity, no need for cryogenic refrigeration, and ease of miniaturization, making them valuable for applications in biomagnetic measurement, magnetic anomaly detection, and non-destructive testing. SERF (Spin-Exchange-Relaxation-Free) atomic magnetometers operate under high atomic number density and near-zero magnetic field conditions, exhibiting high magnetic field detection sensitivity. The pump-probe type SERF atomic magnetometer utilizes the pump to optically polarize alkali metal atoms in an atomic gas cell and uses the Faraday rotation of the probe light to acquire magnetic field information. In actual operation, the output of the atomic magnetometer is affected not only by the measured magnetic field but also by the atomic gas cell temperature, pump light intensity, probe light intensity, and optical path state. Ambient airflow or local thermal disturbances can alter the thermal balance between the oven and the gas cell, causing changes in the alkali metal atom number density, polarization degree, and relaxation state. Fluctuations in laser power, fiber bending, and minute displacements of optical components can alter the pump efficiency and polarization difference detection gain. The aforementioned factors may cause slow drift or low-frequency fluctuations in the magnetometer output, masking the weak magnetic signal and reducing measurement repeatability and long-term stability. Furthermore, the response speed and transmission delay of temperature, pump light, and probe light channels to the same environmental disturbance differ, making it difficult for uncorrected reference signals to accurately correspond to readout offsets in the magnetometer output. When the measured magnetic field changes rapidly, continuously updating compensation parameters may also misinterpret the actual dynamic magnetic field as environmental drift and weaken it, limiting the application of atomic magnetometers in dynamic weak magnetic measurement under complex environments. Summary of the Invention

[0003] The problem addressed by this invention is to propose an atomic magnetometer device and method based on multiple physical reference channels. This allows the atomic magnetometer to simultaneously acquire and time-delay correct three physical reference signals and the main output signal of the magnetometer by utilizing pump light intensity, probe light intensity, and temperature information near the atomic gas cell while measuring weak magnetic fields. Furthermore, it controls the recursive update state of the compensation parameters based on the changing relationship between the main output and the physical reference signals. This reduces output drift caused by environmental disturbances and changes in the magnetometer's operating state, lowers the miscompensation for real dynamic weak magnetic signals, and improves the measurement stability of the atomic magnetometer in complex environments.

[0004] The technical solution of the present invention is as follows:

[0005] An atomic magnetometer device based on multiple physical reference channels is characterized by comprising a first laser, a second laser, an atomic magnetometer sensing unit, and a multi-physical reference synchronous acquisition and compensation system. The first and second lasers are respectively connected to the atomic magnetometer sensing unit, and the multi-physical reference synchronous acquisition and compensation system is connected to the atomic magnetometer sensing unit. The multi-physical reference synchronous acquisition and compensation system includes a multi-channel synchronous acquisition module, a recursive compensation module, and a subtraction operation unit. The multi-channel synchronous acquisition module receives pump light reference signals, probe light reference signals, temperature reference signals, and the main output signal of the magnetometer, forming a synchronous acquisition signal group and transmitting it to the recursive compensation module. The recursive compensation module generates a compensation signal based on the three time-corrected physical reference signals and the controlled recursive update of compensation parameters. The compensation signal is transmitted to the negative input terminal of the subtraction operation unit, and the main output signal of the magnetometer calibrated by the magnetic field is transmitted to the positive input terminal of the subtraction operation unit. The subtraction operation unit outputs a compensated magnetic field output signal obtained by subtracting the compensation signal from the main output signal of the magnetometer calibrated by the magnetic field.

[0006] The atomic magnetometer sensing unit includes an atomic gas chamber located inside an oven equipped with a temperature reference acquisition module. The oven is located within a triaxial magnetic field coil. The pump light input side of the atomic gas chamber is connected to the pump light modulation and reference acquisition module via a steering mirror. The probe light input side of the atomic gas chamber is connected to the probe light modulation and reference acquisition module. The probe light output side of the atomic gas chamber is connected to a polarization difference detection module. The polarization difference detection module outputs the main output signal of the magnetometer. The probe light modulation and reference acquisition module outputs the probe light reference signal through a second reference photodetector. The pump light modulation and reference acquisition module outputs the pump light reference signal through a first reference photodetector. The temperature reference acquisition module outputs the temperature reference signal.

[0007] The first laser is connected to the pump light modulation and reference acquisition module via an optical fiber and a collimator in sequence, and the second laser is connected to the probe light modulation and reference acquisition module via an optical fiber and a collimator in sequence.

[0008] The probe light modulation and reference acquisition module includes a second polarizing beam splitter. The input side of the second polarizing beam splitter is connected to a second laser via a half-wave plate, a second linear polarizer, a collimator, and an optical fiber. The reflection side of the second polarizing beam splitter is connected to a second reference photodetector, and the transmission side of the second polarizing beam splitter is connected to the atomic gas cell. The polarization differential detection module includes a differential detection half-wave plate, a lateral displacement polarizing beam splitter, a differential photodetector group, and a differential transimpedance amplifier circuit connected in sequence. The output terminal of the differential transimpedance amplifier circuit outputs the main output signal of the magnetometer. The differential detection half-wave plate is connected to the atomic gas cell. The pump light modulation and reference acquisition module includes a first polarizing beam splitter. The input side of the first polarizing beam splitter is connected to a first laser via a first linear polarizer, a collimator, and an optical fiber. The reflection side of the first polarizing beam splitter is connected to the first reference photodetector, and the transmission side of the first polarizing beam splitter is connected to the steering mirror via a quarter-wave plate.

[0009] Including the following expressions:

[0010] ,

[0011] ,

[0012] ,

[0013] ,

[0014] ,

[0015] ,

[0016] ,

[0017] in The output signal of the compensated magnetic field is given by k, where k is the kth sampling time and k is a positive integer. This is the main output signal of the magnetometer. To compensate for signal or equivalent magnetic field readout offset;

[0018] in yes transpose, It is the compensation parameter vector at the k-th sampling time. It is the time-corrected reference vector at the k-th sampling time.

[0019] in It is the compensation parameter vector at the (k-1)th sampling time, where μ is the update step size. It is a conditional quantity for recursive update of compensation parameters. It is a reference matrix composed of current and historical reference vectors. yes The transpose of , where δ is the regularization parameter and I is the identity matrix. It is the compensation error vector;

[0020] in It is the main output vector of the magnetometer. This is the main output signal of the magnetometer at the (k-1)th sampling time. This is the main output signal of the magnetometer at the (k-L+1)th sampling time, where L is the projection order in the block affine projection method, L is a positive integer, and the exponent T represents the transpose. It is the time-corrected reference vector at the (k-1)th sampling time. It is the time-corrected reference vector at the (k-L+1)th sampling time, τ p τ is the time delay parameter of the pump optical reference signal relative to the main output signal of the magnetometer. d τ is the time delay parameter of the probe optical reference signal relative to the main output signal of the magnetometer. T It is the time delay parameter of the temperature reference signal relative to the main output signal of the magnetometer. It is r p The correction value of (k), r p (k) is the pump optical reference signal at the k-th sampling time. It is r d The correction value of (k), r d (k) is the probe light reference signal at the k-th sampling time. Yes, r T The correction value of (k), r T (k) is the temperature reference signal at the kth sampling time.

[0021] A method for implementing an atomic magnetometer based on multiple physical reference channels is characterized by including the aforementioned atomic magnetometer device based on multiple physical reference channels.

[0022] Includes the following steps:

[0023] Step 1: Adjust the emission frequency and optical power of the first laser and the second laser so that the first laser generates pump light and the second laser generates probe light; heat the atomic gas cell by heating it in an oven and compensate the triaxial residual magnetic field at the location of the atomic gas cell to near zero field by using a triaxial magnetic field coil;

[0024] Step 2: Input the pump light into the pump light modulation and reference acquisition module to obtain the pump light reference signal, input the probe light into the probe light modulation and reference acquisition module to obtain the probe light reference signal, and obtain the temperature reference signal through the temperature reference acquisition module.

[0025] Step 3: Irradiate the atomic gas cell with pump light to cause spin polarization of the alkali metal atoms in the gas cell, and make the probe light pass through the atomic gas cell in a direction orthogonal to the pump light. The Faraday rotation of the probe light is detected by the polarization difference detection module to obtain the main output signal of the magnetometer.

[0026] Step 4: The pump light reference signal, probe light reference signal, temperature reference signal, and magnetometer main output signal are synchronously acquired through a multi-channel synchronous acquisition module, and the resulting synchronous acquisition signal group is input into the recursive compensation module. The three physical reference signals are time-corrected according to the time delay parameters of each physical reference channel, and the compensation parameters are recursively updated based on the relationship between the magnetometer main output signal and the corrected three physical reference signals to generate a compensation signal. The three physical reference signals are the pump light reference signal, probe light reference signal, and temperature reference signal.

[0027] Step 5: Input the main output signal of the magnetometer into the positive input terminal of the subtraction operation unit, input the compensation signal into the negative input terminal of the subtraction operation unit, and subtract the compensation signal from the main output signal of the magnetometer to obtain the compensated magnetic field output signal.

[0028] The technical effects of this invention are as follows: This invention provides an atomic magnetometer device and method based on multiple physical reference channels. By synchronously sensing the optical state, thermal state, and magnetic field output state of the atomic magnetometer, it achieves online compensation for magnetic field readout drift caused by environmental disturbances. This invention includes a pump light control and reference acquisition module, a probe light control and reference acquisition module, and a temperature reference acquisition module. Through real-time updates of the time delay correction and compensation parameters of the reference channels, it achieves protection of the effective weak magnetic signal under real dynamic magnetic field conditions. Without changing the original SERF atomic magnetometer measurement principle and polarization difference detection method, this scheme can reduce readout drift caused by thermal disturbances, light intensity fluctuations, and changes in optical path state, reduce miscompensation of real dynamic weak magnetic signals, improve measurement stability, environmental adaptability, and dynamic waveform retention capability, and facilitates integration and application in existing atomic magnetometer platforms.

[0029] The advantages of this invention compared to existing technologies are:

[0030] (1) Conventional pump-probe type SERF atomic magnetometers typically only use polarization difference detection signals to measure magnetic fields. When the temperature of the atomic gas cell, the pump light intensity, the probe light intensity, or the optical path state changes, it is difficult to determine the specific source of the output change based on the main output of the magnetometer. This invention sets up optical control and reference acquisition modules before the pump light and probe light enter the atomic gas cell, and sets up a temperature reference acquisition module near the atomic gas cell or oven. This allows the magnetometer to obtain three physical reference signals—pump light, probe light, and temperature—while performing weak magnetic field measurements, and to acquire them synchronously with the main output signal of the magnetometer. This provides a physical reference basis for identifying the magnetic field readout offset caused by changes in temperature and optical state.

[0031] (2) This invention sets up a recursive compensation module to correct the time offset of the three physical reference signals relative to the main output signal of the magnetometer based on the time delay parameters of each physical reference channel. Simultaneously, it controls the recursive update of the compensation parameters based on the combined changes of the main output signal of the magnetometer and the three physical reference signals. The compensation parameters are updated during the normal drift segment and maintained or their update speed is reduced during the real dynamic magnetic field segment. This method can weaken the impact of environmental thermal disturbances, laser power fluctuations, and changes in optical path state on the magnetic field measurement results, reduce miscompensation of the real dynamic weak magnetic signal, and improve the measurement stability, environmental adaptability, and dynamic waveform retention capability of the atomic magnetometer.

[0032] (3) This invention does not change the basic measurement principle and polarization difference detection method of the original SERF atomic magnetometer. It only adds an optical intensity reference branch, a temperature reference acquisition module and a multi-physical reference synchronous acquisition and compensation system. It retains the advantages of the original configuration, such as high sensitivity and easy independent adjustment of optical parameters, and is easy to integrate and apply in the existing atomic magnetometer platform. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the structure of an atomic magnetometer device based on multiple physical reference channels that implements the present invention.

[0034] The reference numerals in the attached figures are explained as follows: 1—First laser (pump laser, the pump light is transmitted through optical fiber and collimated before entering the first linear polarizer 3); 2—Second laser (probe laser, the probe light is transmitted through optical fiber and collimated before entering the second linear polarizer 9); 3—First linear polarizer; 4—First polarizing beam splitter prism; 5—First reference photodetector; 6—Quarter-wave plate; 7—Directing mirror; 8—Pump light reference signal; 9—Second linear polarizer; 10—Probe light half-wave plate; 11—Second polarizing beam splitter prism; 12—Second reference photodetector; 13—Probe light reference signal; 14—Atomic gas chamber; 15—Oven; 16—Temperature reference acquisition module; 17—Temperature reference signal; 18— 19—Differential detection half-wave plate; 20—Lateral displacement polarization beam splitter prism; 21—Differential photodetector group; 22—Differential transimpedance amplifier circuit; 23—Main output signal of magnetometer; 24—Multi-channel synchronous acquisition module; 25—Synchronous acquisition signal group; 26—Recursive compensation module; 27—Subtraction operation unit (with positive input, negative input and output terminals); 28—Compensated magnetic field output signal; 29—Pump light control and reference acquisition module; 30—Probe light control and reference acquisition module; 31—Polarization differential detection module; 32—Atomic magnetometer sensing unit; 33—Multi-physics reference synchronous acquisition and compensation system; xyz—Cartesian coordinate axes (i.e., x-axis, y-axis, and z-axis). Detailed Implementation

[0035] The following is in conjunction with the attached diagram ( Figure 1 The present invention will be described in conjunction with the embodiments.

[0036] Figure 1 This is a schematic diagram of an atomic magnetometer device based on a multi-physics reference channel, which implements the present invention. (Reference) Figure 1As shown, an atomic magnetometer device based on a multi-physics reference channel includes a light source module (including a first laser and a second laser), an atomic magnetometer sensing unit 32, and a multi-physics reference synchronous acquisition and compensation system 33 connected in sequence. The multi-physics reference synchronous acquisition and compensation system 33 includes a multi-channel synchronous acquisition module 24, a recursive compensation module 26, and a subtraction operation unit 27. The multi-channel synchronous acquisition module 24 receives a pump light reference signal 8, a magnetometer main output signal 23, a temperature reference signal 17, and a probe light parameter from the atomic magnetometer sensing unit 32, respectively. After the reference signal 13 is generated, a synchronous acquisition signal group 25 is formed and transmitted to the recursive compensation module 26. The recursive compensation module 26 generates an equivalent magnetic field readout offset as a compensation signal based on the updated compensation parameters and the time-corrected reference vector. The compensation signal is transmitted to the negative input terminal (-) of the subtraction operation unit 27, and the main output signal 23 of the magnetometer is transmitted to the positive input terminal (+) of the subtraction operation unit 27. The output terminal of the subtraction operation unit 27 outputs the compensated magnetic field output signal 28 after subtracting the compensation signal from the main output signal 23 of the magnetometer.

[0037] The atomic magnetometer sensing unit 32 includes an atomic gas chamber 14, which is located inside an oven 15 equipped with a temperature reference acquisition module 16. The oven 15 is located inside a triaxial magnetic field coil 18. The pump light input side of the atomic gas chamber 14 is connected to a pump light modulation and reference acquisition module 29 via a steering reflector 7. The probe light input side of the atomic gas chamber 14 is connected to a probe light modulation and reference acquisition module 30. The probe light output side of the atomic gas chamber 14 is connected to a polarization difference detection module 31. The polarization difference detection module 31 outputs the main output signal 23 of the magnetometer. The probe light modulation and reference acquisition module 30 outputs the probe light reference signal 13 via a second reference photodetector 12. The pump light modulation and reference acquisition module 29 outputs the pump light reference signal 8 via a first reference photodetector 5. The temperature reference acquisition module 16 outputs the temperature reference signal 17.

[0038] The light source module includes a first laser 1 and a second laser 2. The first laser 1 is connected to the pump light modulation and reference acquisition module 29 in sequence through an optical fiber and a collimator. The second laser 2 is connected to the probe light modulation and reference acquisition module 30 in sequence through an optical fiber and a collimator.

[0039] The probe light modulation and reference acquisition module 30 includes a second polarizing beam splitter 11. The input side of the second polarizing beam splitter 11 is connected to the second laser 2 sequentially through a probe light path half-wave plate 10, a second linear polarizer 9, a collimator, and an optical fiber. The reflection side of the second polarizing beam splitter 11 is connected to the second reference photodetector 12, and the transmission side of the second polarizing beam splitter 11 is connected to the atomic gas cell 14. The polarization differential detection module 31 includes a differential detection half-wave plate 19, a lateral displacement polarizing beam splitter 20, a differential photodetector group 21, and a differential detector group 21 connected in sequence. The differential transimpedance amplifier circuit 22 outputs the main output signal 23 of the magnetometer. The differential detection half-wave plate 19 is connected to the atomic gas cell 14. The pump light modulation and reference acquisition module 29 includes a first polarizing beam splitter 4. The input side of the first polarizing beam splitter 4 is connected to the first laser 1 in sequence through a first linear polarizer 3, a collimator and an optical fiber. The reflection side of the first polarizing beam splitter 4 is connected to the first reference photodetector 5. The transmission side of the first polarizing beam splitter 4 is connected to the steering mirror 7 through a quarter-wave plate 6.

[0040] Including the following expressions:

[0041] ,

[0042] ,

[0043] ,

[0044] ,

[0045] ,

[0046] ,

[0047] ,

[0048] in The output signal of the compensated magnetic field is given by k, where k is the kth sampling time and k is a positive integer. This is the main output signal of the magnetometer. To compensate for signal or equivalent magnetic field readout offset;

[0049] in yes transpose, It is the compensation parameter vector at the k-th sampling time. It is the time-corrected reference vector at the k-th sampling time.

[0050] in It is the compensation parameter vector at the (k-1)th sampling time, where μ is the update step size. It is the conditional quantity for the recursive update of the compensation parameters (when the main output of the magnetometer changes rapidly and the three reference signals do not change accordingly, the compensation parameters are maintained or their update speed is reduced). It is a reference matrix composed of current and historical reference vectors. yes The transpose of , where δ is the regularization parameter and I is the identity matrix. It is the compensation error vector;

[0051] in It is the main output vector of the magnetometer. This is the main output signal of the magnetometer at the (k-1)th sampling time. This is the main output signal of the magnetometer at the (k-L+1)th sampling time, where L is the projection order in the block affine projection method, L is a positive integer, and the exponent T represents the transpose. It is the time-corrected reference vector at the (k-1)th sampling time. It is the time-corrected reference vector at the (k-L+1)th sampling time, τ p τ is the time delay parameter of the pump optical reference signal relative to the main output signal of the magnetometer. d τ is the time delay parameter of the probe optical reference signal relative to the main output signal of the magnetometer. T It is the time delay parameter of the temperature reference signal relative to the main output signal of the magnetometer. It is r p The correction value of (k), r p (k) is the pump optical reference signal at the k-th sampling time. It is r d The correction value of (k), r d (k) is the probe light reference signal at the k-th sampling time. Yes, r T The correction value of (k), r T (k) is the temperature reference signal at the kth sampling time.

[0052] A method for implementing an atomic magnetometer based on multiple physical reference channels is characterized by including the aforementioned atomic magnetometer device based on multiple physical reference channels.

[0053] Includes the following steps:

[0054] Step 1: Adjust the emission frequency and optical power of the first laser 1 and the second laser 2 so that the first laser 1 generates pump light and the second laser 2 generates probe light; heat the atomic gas chamber 14 through the oven 15 and compensate the triaxial residual magnetic field at the location of the atomic gas chamber 14 to near zero field through the triaxial magnetic field coil 18.

[0055] Step 2: Input the pump light into the pump light modulation and reference acquisition module 29 to obtain the pump light reference signal 8, input the probe light into the probe light modulation and reference acquisition module 30 to obtain the probe light reference signal 13, and obtain the temperature reference signal 17 through the temperature reference acquisition module 16.

[0056] Step 3: Irradiate the atomic gas cell 14 with pump light to cause spin polarization of the alkali metal atoms in the gas cell, and make the probe light pass through the atomic gas cell 14 in a direction orthogonal to the pump light. The Faraday rotation of the probe light is detected by the polarization difference detection module 31 to obtain the main output signal of the magnetometer.

[0057] Step 4: The pump light reference signal 8, probe light reference signal 13, temperature reference signal 17, and magnetometer main output signal 23 are synchronously acquired by the multi-channel synchronous acquisition module 24, and the resulting synchronous acquisition signal group 25 is input into the recursive compensation module 26. The three physical reference signals are time-corrected according to the time delay parameters of each physical reference channel, and the compensation parameters are recursively updated according to the relationship between the magnetometer main output signal 23 and the corrected three physical reference signals to generate a compensation signal. The three physical reference signals are the pump light reference signal 8, probe light reference signal 13, and temperature reference signal 17.

[0058] Step 5: Input the main output signal 23 of the magnetometer into the positive input terminal (+) of the subtraction operation unit 27, input the compensation signal into the negative input terminal (-) of the subtraction operation unit 27, and subtract the compensation signal from the main output signal 23 of the magnetometer to obtain the compensated magnetic field output signal.

[0059] This invention proposes an atomic magnetometer device and method based on multiple physical reference channels. By synchronously sensing the optical, thermal, and magnetic field output states of the atomic magnetometer, online compensation for magnetic field readout drift caused by environmental disturbances is achieved. The invention incorporates pump light control and reference acquisition modules, probe light control and reference acquisition modules, and temperature reference acquisition modules. Through real-time updates of time delay correction and compensation parameters of the reference channels, protection of effective weak magnetic signals under real dynamic magnetic field conditions is achieved. Without altering the original SERF atomic magnetometer measurement principle and polarization differential detection method, this scheme can reduce readout drift caused by thermal disturbances, light intensity fluctuations, and changes in optical path state, reduce miscompensation of real dynamic weak magnetic signals, improve measurement stability, environmental adaptability, and dynamic waveform retention capability, and facilitate integration into existing atomic magnetometer platforms.

[0060] An atomic magnetometer device and method based on a multi-physical reference channel includes a first laser (1), a second laser (2), an atomic magnetometer sensing unit (32), and a multi-physical reference synchronous acquisition and compensation system (33). The pump light generated by the first laser (1) and the probe light generated by the second laser (2) are respectively input into the atomic magnetometer sensing unit (32). The atomic magnetometer sensing unit (32) obtains the pump light reference signal (8), the probe light reference signal (13), the temperature reference signal (17), and the magnetometer main output signal (23). The multi-physical reference synchronous acquisition and compensation system (33) includes a multi-channel synchronous acquisition module. Block (24), recursive compensation module (26) and subtraction operation unit (27), multi-channel synchronous acquisition module (24) synchronously acquires the above four signals and forms a synchronous acquisition signal group (25), recursive compensation module (26) performs time correction on three physical reference signals according to the time delay parameters of each physical reference channel, controls the recursive update of compensation parameters and generates compensation signals according to the change relationship between the main output signal (23) of the magnetometer and the three physical reference signals after time correction, and subtracts the compensation signal from the main output signal (23) of the magnetometer to obtain the compensated magnetic field output signal (28).

[0061] The atomic magnetometer sensing unit (32) includes a pump light control and reference acquisition module (29). The pump light control and reference acquisition module (29) includes a first linear polarizer (3), a first polarizing beam splitter (4), a first reference photodetector (5), and a quarter-wave plate (6). The reference light split by the first polarizing beam splitter (4) is received by the first reference photodetector (5). The first reference photodetector (5) outputs a pump light reference signal (8) corresponding to the intensity of the reference light. The remaining pump light is irradiated into the atomic gas cell (14) after passing through the quarter-wave plate (6) and the deflecting mirror (7).

[0062] The atomic magnetometer sensing unit (32) includes a probe light control and reference acquisition module (30). The probe light control and reference acquisition module (30) includes a second linear polarizer (9), a probe light path half-wave plate (10), a second polarizing beam splitter (11), and a second reference photodetector (12). The reference light split by the second polarizing beam splitter (11) is received by the second reference photodetector (12). The second reference photodetector (12) outputs a probe light reference signal (13) corresponding to the intensity of the reference light. The remaining probe light passes through the atomic gas cell (14).

[0063] The atomic magnetometer sensing unit (32) includes an atomic gas chamber (14), an oven (15), a temperature reference acquisition module (16), and a triaxial magnetic field coil (18). The atomic gas chamber (14) is located inside the oven (15). The temperature reference acquisition module (16) includes a Pt1000 platinum resistance thermometer, a thermally conductive insulating layer, and a temperature signal conditioning circuit. The Pt1000 platinum resistance thermometer is attached to the oven (15) near the atomic gas chamber (14) through the thermally conductive insulating layer. The temperature signal conditioning circuit converts the resistance change of the Pt1000 platinum resistance thermometer into a voltage signal corresponding to the temperature, and forms a temperature reference signal (17) after amplification and low-pass filtering by the instrument. The triaxial magnetic field coil (18) is located around the atomic gas chamber (14) and is used to compensate for the triaxial residual magnetic field at the location of the atomic gas chamber (14).

[0064] The atomic magnetometer sensing unit (32) includes a polarization differential detection module (31), which includes a differential detection half-wave plate (19), a lateral displacement polarization beam splitter (20), a differential photodetector group (21), and a differential transimpedance amplifier circuit (22). The differential photodetector group (21) includes a first photodetector and a second photodetector that receive two orthogonal polarization components respectively. The differential transimpedance amplifier circuit (22) performs differential and amplification on the two photocurrents to obtain the main output signal (23) of the magnetometer.

[0065] The multi-channel synchronous acquisition module (24) includes at least four synchronous acquisition channels with a common sampling clock, which are used to acquire pump light reference signal (8), probe light reference signal (13), temperature reference signal (17) and magnetometer main output signal (23), respectively, and form a synchronous acquisition signal group (25).

[0066] The recursive compensation module (26) performs time delay correction on the three physical reference signals in the synchronous acquisition signal group (25), and determines the update state of the compensation parameters according to the relationship between the main output signal (23) of the magnetometer and the changes of the three physical reference signals after correction. When the change of the main output signal (23) of the magnetometer is greater than the first threshold and the combined change of the three physical reference signals after correction is less than the second threshold, the compensation parameters are maintained or their update speed is reduced. In other states, the compensation parameters are recursively updated, and then the compensation signal is generated according to the updated compensation parameters.

[0067] The subtraction operation unit (27) includes a main output input terminal, a compensation signal input terminal and a signal output terminal; the main output signal (23) of the magnetometer is input to the main output input terminal, the compensation signal generated by the recursive compensation module (26) is input to the compensation signal input terminal, the subtraction operation unit (27) subtracts the compensation signal from the main output signal (23) of the magnetometer, and outputs the compensated magnetic field output signal (28) through the signal output terminal.

[0068] A method for implementing an atomic magnetometer based on multiple physical reference channels includes employing the aforementioned atomic magnetometer device based on multiple physical reference channels, and the following steps:

[0069] Step 1: Adjust the emission frequency and optical power of the first laser (1) and the second laser (2) so that the first laser (1) generates pump light and the second laser (2) generates probe light; heat the atomic gas chamber (14) through the oven (15) and compensate the triaxial residual magnetic field at the location of the atomic gas chamber (14) to near zero field through the triaxial magnetic field coil (18);

[0070] Step 2: Input the pump light and probe light into the pump light control and reference acquisition module (29) and the probe light control and reference acquisition module (30) respectively to obtain the pump light reference signal (8) and the probe light reference signal (13), and obtain the temperature reference signal (17) through the temperature reference acquisition module (16).

[0071] Step 3: Irradiate the atomic gas cell (14) with pump light to cause spin polarization of the alkali metal atoms in the gas cell, and make the probe light pass through the atomic gas cell (14) in the direction intersecting with the pump light. The Faraday rotation of the probe light is detected by the polarization difference detection module (31) to obtain the main output signal of the magnetometer (23).

[0072] Step 4: The pump light reference signal (8), probe light reference signal (13), temperature reference signal (17) and magnetometer main output signal (23) are synchronously acquired by the multi-channel synchronous acquisition module (24), and the resulting synchronous acquisition signal group (25) is input into the recursive compensation module (26); the three physical reference signals are time-corrected according to the time delay parameters of each physical reference channel, and the recursive update of the compensation parameters is controlled according to the relationship between the magnetometer main output signal (23) and the three corrected physical reference signals to generate a compensation signal;

[0073] Step 5: Input the main output signal (23) of the magnetometer into the positive input terminal of the subtraction operation unit (27), input the compensation signal into the negative input terminal of the subtraction operation unit (27), subtract the compensation signal from the main output signal (23) of the magnetometer, and obtain the compensated magnetic field output signal (28).

[0074] See Figure 1The atomic magnetometer device and method based on multi-physical reference channels provided by this invention mainly include a first laser 1, a second laser 2, an atomic magnetometer sensing unit 32, and a multi-physical reference synchronous acquisition and compensation system 33; the atomic magnetometer sensing unit 32 includes a pump light control and reference acquisition module 29, a probe light control and reference acquisition module 30, a steering mirror 7, an atomic gas chamber 14, an oven 15, a temperature reference acquisition module 16, a triaxial magnetic field coil 18, and a polarization difference detection module 31; the multi-physical reference synchronous acquisition and compensation system 33 includes a multi-channel synchronous acquisition module 24, a recursive compensation module 26, and a subtraction operation unit 27.

[0075] like Figure 1 As shown, the specific implementation steps of the present invention are as follows:

[0076] (1) Adjust the output frequency and optical power of the first laser 1 and the second laser 2 so that the first laser 1 generates pump light and the second laser 2 generates probe light. After being transmitted and collimated by optical fiber, the pump light passes sequentially through the first linear polarizer 3 and the first polarizing beam splitter 4. The separated reference light is received by the first reference photodetector 5 and forms the pump light reference signal 8. The remaining pump light is adjusted by the quarter-wave plate 6 and then reflected by the deflecting mirror 7 to illuminate the atomic gas cell 14. After being transmitted and collimated by optical fiber, the probe light passes sequentially through the second linear polarizer 9, the probe light path half-wave plate 10, and the second polarizing beam splitter 11. The separated reference light is received by the second reference photodetector 12 and forms the probe light reference signal 13. The remaining probe light passes through the atomic gas cell 14.

[0077] (2) The oven 15 is used to heat the atomic gas chamber 14 so that the alkali metal atoms in the gas chamber reach the atomic number density required for SERF operation; the triaxial magnetic field coil 18 is used to compensate the triaxial residual magnetic field at the location of the atomic gas chamber 14. The Pt1000 platinum resistance in the temperature reference acquisition module 16 is attached to the oven 15 near the atomic gas chamber 14 through a thermally conductive insulating fixing layer, so that the Pt1000 platinum resistance and the oven 15 are thermally coupled and electrically insulated; the temperature signal conditioning circuit converts the resistance change of the Pt1000 platinum resistance into a voltage signal corresponding to the temperature, and forms a temperature reference signal 17 after instrument amplification and low-pass filtering.

[0078] (3) The alkali metal atoms in the circularly polarized pump light polarize the atomic gas cell 14, and the linearly polarized probe light passes through the atomic gas cell 14 in the direction intersecting with the pump light. The transmitted probe light carries Faraday rotation information related to the magnetic field to be measured, and passes sequentially through the differential detection half-wave plate 19 and the lateral displacement polarization beam splitter prism 20. The two orthogonal polarization components are received by the differential photodetector group 21, and after being processed by the differential transimpedance amplifier circuit 22, they form the main output signal 23 of the magnetometer. Under near-zero magnetic field, steady-state and small signal conditions, the magnetometer output can be approximately expressed as:

[0079] ,

[0080] In the formula, V m (k) represents the magnetometer voltage output at the k-th sampling time; K is the equivalent coefficient that includes the atomic cell length, optical rotation response, and differential detection conversion relationship; I d (k) represents the probe light intensity; n[T(k)] represents the alkali metal atom number density within the atomic gas chamber at temperature T(k); γ e is the electron gyromagnetic ratio; s is the photon spin polarization of the pump light; R op [I p [k] represents the pump light intensity I p (k) corresponds to the optical pump rate; R rel (k) represents the equivalent relaxation rate excluding optical pumping under the current temperature and chamber conditions; B y (k) represents the magnetic field to be measured along the sensitive axis; V0(k) represents the output offset caused by optical path imbalance and electronic bias. From this equation, it can be seen that the pump light intensity, probe light intensity, and temperature change affect the magnetometer output through optical pump rate, optical readout gain, atomic number density, and equivalent relaxation rate, respectively.

[0081] (4) The pump light reference signal 8, probe light reference signal 13, temperature reference signal 17, and magnetometer main output signal 23 are connected to the multi-channel synchronous acquisition module 24 to synchronously acquire the four signals, and the synchronous acquisition signal group 25 is transmitted to the recursive compensation module 26. The static operating point is removed from the pump light reference signal, probe light reference signal, and temperature reference signal respectively, and the three physical reference signals after processing are denoted as r. p (k), r d (k) and r T (k), the magnetometer's main output signal 23, after calibration, is recorded as... .

[0082] Under conditions of no applied magnetic field or an applied known calibration magnetic field, cross-correlation analysis was used to obtain the time correspondence between the three physical reference signals and the low-frequency components of the magnetometer's main output. The sampling offset corresponding to the maximum correlation was determined as the channel delay parameter τ. p τ d and τ T The channel delay parameters can be pre-calibrated and stored in the recursive compensation module 26, or they can be updated within a sliding time window based on continuously acquired data.

[0083] The recursive compensation module 26 performs sampling point shifting or interpolation processing on the three physical reference signals according to the corresponding channel delay parameters, and constructs a time-corrected reference vector:

[0084] ,

[0085] In the formula, τ p τ d and τ T These are the time delay parameters of the pump light reference channel, probe light reference channel, and temperature reference channel relative to the main output signal of the magnetometer, respectively. r(k) is the time-corrected reference vector at the k-th sampling time.

[0086] The recursive compensation module 26 determines the update state of the compensation parameters based on the changes in the magnetometer's main output signal and the changes in the reference vector. When the magnetometer's main output signal changes rapidly, but the three physical reference signals do not change accordingly, the update control quantity satisfies:

[0087] ,

[0088] In other cases:

[0089] ,

[0090] In the formula, ΔB m (k) represents the main output signal B of the magnetometer. m η is the change in adjacent samples of (k), where Δr(k) is the change in adjacent samples of the reference vector after time correction; B η is the threshold value for the main output change of the magnetometer. r The threshold value for the physical reference signal change is used; when g(k) = 0, the current compensation parameter is maintained; when g(k) = 1, the compensation parameter is allowed to be updated recursively. When it is necessary to slow down rather than completely stop the parameter update, g(k) takes a value between 0 and 1.

[0091] In a preferred embodiment, the recursive compensation module 26 updates the compensation parameters using a block affine projection method. The reference matrix U(k) is composed of the current and historical reference vectors:

[0092] ,

[0093] The corresponding main output vector b(k) of the magnetometer is:

[0094] ,

[0095] The corresponding error vector is:

[0096] ,

[0097] The compensation parameters are updated recursively according to the following formula:

[0098] ,

[0099] In the formula, L is the projection order, μ is the update step size, δ is the regularization parameter, I is the identity matrix, w(k) is the compensation parameter vector at the k-th sampling time, and e(k) is the compensation error vector.

[0100] The recursive compensation module 26 generates an equivalent magnetic field readout offset based on the updated compensation parameters and the time-corrected reference vector.

[0101] ,

[0102] In the formula, The equivalent magnetic field readout offset is estimated by the recursive compensation module 26. The block affine projection method is a preferred embodiment, but the recursive compensation module 26 can also adopt other equivalent methods that can recursively update the compensation parameters based on multiple physical reference signals.

[0103] (5) The calibrated magnetometer main output and the equivalent magnetic field readout offset output by the recursive compensation module 26 Inputting the subtraction unit 27 yields the compensated magnetic field output signal 28, whose expression is:

[0104] ,

[0105] In the formula, To compensate for the magnetic field output signal, This is the magnetic field signal obtained after calibration from the main output of the magnetometer. The equivalent magnetic field readout offset estimated by the recursive compensation module 26.

[0106] In summary, this invention provides an atomic magnetometer device and method based on multiple physical reference channels. It transforms the optical and thermal states of the magnetometer, which are susceptible to environmental influences during operation, into observable and usable reference information. Time correction and parameter updates are performed during the recursive compensation process, enabling the magnetic field output changes to be judged and corrected in conjunction with the device's own operating status. This approach does not alter the measurement principle and polarization differential readout structure of traditional pump-probe atomic magnetometers. It reduces output drift caused by non-magnetic factors while minimizing miscompensation for real dynamic weak magnetic signals, thus improving the stability and dynamic waveform retention capability of the atomic magnetometer under continuous measurement, complex environments, and long-term operating conditions.

[0107] Contents not described in detail in this specification are prior art known to those skilled in the art. It is hereby indicated that the above description is intended to help those skilled in the art understand this invention, but does not limit the scope of protection of this invention. Any equivalent substitutions, modifications, improvements, and / or simplifications of the above descriptions that do not depart from the essential content of this invention fall within the scope of protection of this invention.

Claims

1. An atomic magnetometer device based on a multi-physics reference channel, characterized in that, The system includes a first laser, a second laser, an atomic magnetometer sensing unit, and a multi-physics reference synchronous acquisition and compensation system. The first and second lasers are connected to the atomic magnetometer sensing unit, and the multi-physics reference synchronous acquisition and compensation system is also connected to the atomic magnetometer sensing unit. The multi-physics reference synchronous acquisition and compensation system includes a multi-channel synchronous acquisition module, a recursive compensation module, and a subtraction operation unit. The multi-channel synchronous acquisition module receives pump light reference signals, probe light reference signals, temperature reference signals, and the main output signal of the magnetometer, forming a synchronous acquisition signal group and transmitting it to the recursive compensation module. The recursive compensation module generates a compensation signal based on the three time-corrected physical reference signals and the controlled recursive update of the compensation parameters. The compensation signal is transmitted to the negative input terminal of the subtraction operation unit, and the main output signal of the magnetometer calibrated by the magnetic field is transmitted to the positive input terminal of the subtraction operation unit. The subtraction operation unit outputs a compensated magnetic field output signal obtained by subtracting the compensation signal from the main output signal of the magnetometer calibrated by the magnetic field.

2. The atomic magnetometer device based on a multi-physics reference channel according to claim 1, characterized in that, The atomic magnetometer sensing unit includes an atomic gas chamber located inside an oven equipped with a temperature reference acquisition module. The oven is located within a triaxial magnetic field coil. The pump light input side of the atomic gas chamber is connected to the pump light modulation and reference acquisition module via a steering mirror. The probe light input side of the atomic gas chamber is connected to the probe light modulation and reference acquisition module. The probe light output side of the atomic gas chamber is connected to a polarization difference detection module. The polarization difference detection module outputs the main output signal of the magnetometer. The probe light modulation and reference acquisition module outputs the probe light reference signal through a second reference photodetector. The pump light modulation and reference acquisition module outputs the pump light reference signal through a first reference photodetector. The temperature reference acquisition module outputs the temperature reference signal.

3. The atomic magnetometer device based on a multi-physics reference channel according to claim 2, characterized in that, The first laser is connected to the pump light modulation and reference acquisition module via an optical fiber and a collimator in sequence, and the second laser is connected to the probe light modulation and reference acquisition module via an optical fiber and a collimator in sequence.

4. The atomic magnetometer device based on a multi-physics reference channel according to claim 2, characterized in that, The probe light modulation and reference acquisition module includes a second polarizing beam splitter. The input side of the second polarizing beam splitter is connected to a second laser via a half-wave plate, a second linear polarizer, a collimator, and an optical fiber. The reflection side of the second polarizing beam splitter is connected to a second reference photodetector, and the transmission side of the second polarizing beam splitter is connected to the atomic gas cell. The pump light modulation and reference acquisition module includes a first polarizing beam splitter. The input side of the first polarizing beam splitter is connected to a first laser via a first linear polarizer, a collimator, and an optical fiber. The reflection side of the first polarizing beam splitter is connected to the first reference photodetector, and the transmission side of the first polarizing beam splitter is connected to the steering mirror via a quarter-wave plate. The polarization differential detection module includes a differential detection half-wave plate, a lateral displacement polarizing beam splitter, a differential photodetector group, and a differential transimpedance amplifier circuit connected in sequence. The output terminal of the differential transimpedance amplifier circuit outputs the main output signal of the magnetometer, and the differential detection half-wave plate is connected to the atomic gas cell.

5. The atomic magnetometer device based on multiple physics reference channels according to claim 1, characterized in that, Including the following expressions: ， ， ， ， ， ， ， in The output signal of the compensated magnetic field, where k is the kth sampling time, and k is a positive integer. This is the main output signal of the magnetometer. To compensate for signal or equivalent magnetic field readout offset; in yes transpose, It is the compensation parameter vector at the k-th sampling time. It is the time-corrected reference vector at the k-th sampling time. in It is the compensation parameter vector at the (k-1)th sampling time, where μ is the update step size. It is a conditional quantity for recursive update of compensation parameters. It is a reference matrix composed of current and historical reference vectors. yes The transpose of , where δ is the regularization parameter and I is the identity matrix. It is the compensation error vector; in It is the main output vector of the magnetometer. This is the main output signal of the magnetometer at the (k-1)th sampling time. This is the main output signal of the magnetometer at the (k-L+1)th sampling time, where L is the projection order in the block affine projection method, L is a positive integer, and the exponent T represents the transpose. It is the time-corrected reference vector at the (k-1)th sampling time. It is the time-corrected reference vector at the (k-L+1)th sampling time, τ p τ is the time delay parameter of the pump optical reference signal relative to the main output signal of the magnetometer. d τ is the time delay parameter of the probe optical reference signal relative to the main output signal of the magnetometer. T It is the time delay parameter of the temperature reference signal relative to the main output signal of the magnetometer. It is r p The correction value of (k), r p (k) is the pump optical reference signal at the k-th sampling time. It is r d The correction value of (k), r d (k) is the probe light reference signal at the k-th sampling time. Yes, r T The correction value of (k), r T (k) is the temperature reference signal at the kth sampling time.

6. A method for implementing an atomic magnetometer based on multiple physical reference channels, characterized in that, This includes the atomic magnetometer device based on a multi-physics reference channel as described in any one of claims 1-5.

7. The method for implementing an atomic magnetometer based on multiple physics reference channels according to claim 6, characterized in that, Includes the following steps: Step 1: Adjust the emission frequency and optical power of the first laser and the second laser so that the first laser generates pump light and the second laser generates probe light; heat the atomic gas cell by heating it in an oven and compensate the triaxial residual magnetic field at the location of the atomic gas cell to near zero field by using a triaxial magnetic field coil; Step 2: Input the pump light into the pump light modulation and reference acquisition module to obtain the pump light reference signal, input the probe light into the probe light modulation and reference acquisition module to obtain the probe light reference signal, and obtain the temperature reference signal through the temperature reference acquisition module. Step 3: Irradiate the atomic gas cell with pump light to cause spin polarization of the alkali metal atoms in the gas cell, and make the probe light pass through the atomic gas cell in a direction orthogonal to the pump light. The Faraday rotation of the probe light is detected by the polarization difference detection module to obtain the main output signal of the magnetometer. Step 4: The pump light reference signal, probe light reference signal, temperature reference signal, and magnetometer main output signal are synchronously acquired through a multi-channel synchronous acquisition module, and the resulting synchronous acquisition signal group is input into the recursive compensation module. The three physical reference signals are time-corrected according to the time delay parameters of each physical reference channel, and the compensation parameters are recursively updated based on the relationship between the magnetometer main output signal and the corrected three physical reference signals to generate a compensation signal. The three physical reference signals are the pump light reference signal, probe light reference signal, and temperature reference signal. Step 5: Input the main output signal of the magnetometer into the positive input terminal of the subtraction operation unit, input the compensation signal into the negative input terminal of the subtraction operation unit, and subtract the compensation signal from the main output signal of the magnetometer to obtain the compensated magnetic field output signal.

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