Micro-miniature modularized single-beam double-axis SERF atom magnetometer

Abstract

A microminiature modularized single-beam double-axis SERF atom magnetometer provides a novel measurement means for biomagnetic measurement and basic physics research, has huge application potential in the aspect of high-performance functional imaging, has great significance in neuroscience and brain science clinical research, greatly simplifies the complexity of a magnetometer system through microminiature modularization, and has the advantages of being simple in structure, convenient to operate and high in practicability. The light source module provides resonance pump light of which the power is stably tuned to a D1 spectral absorption line; the sensing module adopts a single-beam transverse magnetic field modulation scheme, pumping and detection are met by using a beam of laser, simultaneous measurement of two extremely-weak magnetic fields which are mutually orthogonal in the transverse direction is realized, and the complexity of a light path is greatly reduced; the electric control module is responsible for functions of temperature control, magnetic field control, detection signal acquisition and processing and the like, temperature control, magnetic field control and signal acquisition and processing are integrated, the complexity of an electronic system is simplified, and high integration under a small size can be realized.

Description

Technical Field

[0001] This invention relates to the field of extremely weak magnetic field measurement, specifically to a miniature modular single-beam biaxial SERF atomic magnetometer, which has the advantages of miniaturization, modularity and high sensitivity, and is conducive to the construction of multi-channel arrayed magnetometers, and can be applied to fields such as magnetocardiography and magnetoencephalography. Background Technology

[0002] Biomedical weak magnetic field measurement based on a highly sensitive miniaturized atomic magnetometer array is a novel functional imaging technology. It is non-contact, high-resolution, and harmless to the human body. It can monitor and image the functional activities of organs such as the brain and heart in real time and accurately, and can obtain complete human functional information. It has great application prospects in the fields of disease prevention, health monitoring and clinical medicine.

[0003] Atomic magnetometers, as an emerging technology, offer a novel measurement method for biomagnetic measurements and fundamental physics research. However, several challenges remain in practical applications. These include: SERF atomic magnetometers currently used for magnetocardiography and magnetoencephalography typically have only one sensing axis (SERF, Spin-Exchange Relaxation-Free), which hinders improvements in spatial resolution and accuracy of magnetic source localization; the large size of current magnetometer probes hinders miniaturization and sensor array implementation; the overly complex operating system utilizes a series of large commercial instruments for different functions, increasing system redundancy and operational complexity; and the excessive power and signal cables hinder portability and integration. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention proposes a miniature modular single-beam biaxial SERF atomic magnetometer, which features miniaturization, modularity, integration, and high sensitivity. It can also achieve simultaneous biaxial magnetic field measurement and can be applied to fields such as magnetocardiography and magnetoencephalography.

[0005] The technical solution of the present invention is as follows:

[0006] A miniature modular single-beam dual-axis SERF atomic magnetometer is characterized by comprising a light source module integrating a laser, a sensing module integrating a magnetometer probe, and an electronic control module integrating a temperature control module, a magnetic control module, and a signal acquisition and processing module. The electronic control module is connected to the light source module and the sensing module via signal cables. The temperature control module, the magnetic control module, and the signal acquisition and processing module are all connected to a host computer. The resonant pump light emitted from the laser is guided into the magnetometer probe through a polarization-maintaining fiber. The resonant pump light polarizes alkali metal atoms in the gas chamber of the sensing module and is emitted from the gas chamber into a photodetector, forming independent dual-axis magnetic field information with a phase difference of π / 2. The signal acquisition and processing module demodulates and separates the dual-axis signal from the dual-axis magnetic field information using a synchronous demodulation method and outputs it to the host computer.

[0007] The magnetometer probe includes a collimator, a polarizer, a half-wave plate, and a polarizing beam splitter connected in sequence. The collimator is connected to the laser via a polarization-maintaining fiber. The transmission side of the polarizing beam splitter is connected to a first photodetector via a quarter-wave plate and a gas cell. The reflection side of the polarizing beam splitter is connected to a second photodetector. The gas cell is enclosed by an oven made of aluminum nitride or boron nitride. There is a heating film on each side of the oven to perform high-frequency non-magnetic heating of the gas cell. The oven is located inside a miniature three-dimensional flexible coil. A platinum resistance thermometer (Pt1000) close to the oven monitors the temperature of the gas cell in real time and transmits the data back to the electronic control module to form a closed-loop mode for real-time PID control of the gas cell temperature. The miniature three-dimensional flexible coil is used to apply a rotational modulation field in the xy transverse plane to manipulate the atomic ensemble.

[0008] The chamber is filled with one of three alkali metals: potassium, rubidium, and cesium. The chamber is also filled with buffer gas helium and quenching gas nitrogen.

[0009] The resonant pump light emitted by the laser is a resonant pump light whose power is stably tuned to the D1 spectral absorption line.

[0010] The micro-miniature three-dimensional flexible coils apply x-axis modulated magnetic fields respectively. and y-axis modulated magnetic field and All are amplitudes, ω is frequency, and t is time.

[0011] The expression for the magnetic field B induced by the atomic ensemble is as follows:

[0012]

[0013] Among them B x0 It is the static magnetic field along the x-axis, B y0 It is the static magnetic field along the y-axis, B z0It is the static magnetic field along the z-axis.

[0014] The ratio of transmitted light intensity to reflected light intensity is adjusted by adjusting the fast axis of the half-wave plate, and the magnitude of the light power in front of the incident gas chamber is monitored by the second photodetector.

[0015] The technical effects of this invention are as follows: This invention discloses a miniature modular single-beam dual-axis SERF atomic magnetometer, a high-performance magnetic field detection device with modular design. It provides a novel measurement method for biomagnetic measurement and fundamental physics research, has great application potential in high-performance functional imaging, and is of great significance to neuroscience and clinical brain science research. The device is divided into a light source module, a sensing module, and an electronic control module, greatly simplifying the complexity of the magnetometer system. The light source module provides resonant pump light with stable power tuning to the D1 spectral absorption line; the sensing module adopts a single-beam transverse magnetic field modulation scheme, using a single laser beam to satisfy both pumping and detection, achieving simultaneous measurement of two extremely weak magnetic fields in mutually orthogonal transverse directions, greatly reducing optical path complexity; the electronic control module is responsible for temperature control, magnetic field control, and detection signal acquisition and processing. This invention, through modular design, reduces optical path complexity, greatly shrinks the size of the atomic magnetometer probe, and integrates temperature control, magnetic field control, and signal acquisition and processing into one unit, simplifying the complexity of the electronic system and achieving high integration in a small volume.

[0016] The advantages of this invention compared with the prior art are as follows: This invention greatly reduces the size of the atomic magnetometer sensor itself through modular design, and can simultaneously sense magnetic field information in two directions. Compared with a single-axis atomic magnetometer, it provides more complete magnetic field information, improves measurement efficiency and integration. In addition, temperature control, magnetic field control and signal acquisition and processing are concentrated in the electronic control module, which simplifies the complexity of the electronic system and enables high integration in a small size. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of a micro-modular single-beam biaxial SERF atomic magnetometer that implements the present invention.

[0018] Figure 2 yes Figure 1 Schematic diagram of the probe structure of the medium magnetometer.

[0019] The following are the annotations in the attached diagram: 1-Light source module; 2-Laser; 3-Polarization-maintaining fiber; 4-Signal cable; 5-Collimator; 6-Magnetometer probe; 7-Sensing module; 8-Temperature control module; 9-Electrical control module; 10-Magnetic control module; 11-Signal acquisition and processing module; 12-Host computer; 13-Polarizer; 14-1 / 2 waveplate; 15-Pump light; 16-Polarization beam splitter; 17-1 / 4 waveplate; 18-Miniature three-dimensional flexible coil; 19-Alkali metal atom; 20-Gas chamber; 21-Heating film; 22-Photodetector; XYZ-Cartesian coordinate system (i.e., X-axis, Y-axis, and Z-axis). Detailed Implementation

[0020] The following is in conjunction with the attached diagram ( Figures 1-2 The invention will be described in the following sections and examples.

[0021] Figure 1 This is a schematic diagram of a micro-modular single-beam biaxial SERF atomic magnetometer that implements the present invention. Figure 2 yes Figure 1 Schematic diagram of the probe structure of a medium magnetometer. (Reference) Figures 1 to 2 As shown, a miniature modular single-beam dual-axis SERF atomic magnetometer includes a light source module 1 integrating a laser 2, a sensing module 7 integrating a magnetometer probe 6, and an electronic control module 9 integrating a temperature control module 8, a magnetic control module 10, and a signal acquisition and processing module 11. The electronic control module 9 is connected to the light source module 1 and the sensing module 7 via signal cables 4. The temperature control module 8, the magnetic control module 10, and the signal acquisition and processing module 11 are all connected to a host computer 12. The resonant pump light (i.e., pump light 15) emitted from the laser 2 is guided into the magnetometer probe 6 through a polarization-maintaining fiber 3. The resonant pump light polarizes the alkali metal atoms 19 in the gas chamber 20 of the sensing module 7 and is then emitted from the gas chamber 20 into the photodetector 22 (i.e., the first photodetector) to form independent dual-axis magnetic field information with a phase difference of π / 2. The signal acquisition and processing module 11 demodulates and separates the dual-axis signal from the dual-axis magnetic field information using a synchronous demodulation method and outputs it to the host computer 12.

[0022] The magnetometer probe 6 includes a collimator 5, a polarizer 13, a half-wave plate 14, and a polarizing beam splitter 16 connected in sequence. The collimator 5 is connected to the laser 2 via a polarization-maintaining fiber 3. The transmission side of the polarizing beam splitter 16 is connected to a first photodetector via a quarter-wave plate 14 and a gas chamber 20. The reflection side of the polarizing beam splitter 16 is connected to a second photodetector (i.e., a photodetector 22 before entering the gas chamber). The gas chamber 20 is enclosed by an oven made of aluminum nitride or boron nitride. There is a heating film 21 on each side of the oven to perform high-frequency non-magnetic heating of the gas chamber 20. The oven is located inside a miniature three-dimensional flexible coil 18. A platinum resistance thermometer Pt1000 close to the oven monitors the temperature of the gas chamber in real time and transmits the data back to the electronic control module 9 to form a closed-loop mode for real-time PID control (PID, proportional-integral-derivative control) of the gas chamber temperature. The miniature three-dimensional flexible coil 18 is used to apply a rotational modulation field on the xy transverse plane to manipulate the atomic ensemble.

[0023] The gas chamber 20 is filled with one of three alkali metals: potassium, rubidium, and cesium. It is also filled with buffer gas helium and quenching gas nitrogen. The resonant pump light emitted from the laser 2 is a resonant pump light whose power is stably tuned to the D1 spectral absorption line.

[0024] The micro-miniature three-dimensional flexible coil 18 applies an x-axis modulated magnetic field. and y-axis modulated magnetic field and All are amplitudes, ω is frequency, and t is time. The expression for the magnetic field B induced by the atomic ensemble is as follows:

[0025]

[0026] Among them B x0 It is the static magnetic field along the x-axis, B y0 It is the static magnetic field along the y-axis, B z0 It is the static magnetic field along the z-axis.

[0027] The ratio of transmitted light intensity to reflected light intensity is adjusted by adjusting the fast axis of the half-wave plate 14, and the magnitude of the light power in front of the incident gas chamber is monitored by the second photodetector.

[0028] A miniaturized, modular, single-beam, dual-axis SERF atomic magnetometer provides a novel measurement method for biomagnetic measurements and fundamental physics research. It has significant application potential in high-performance functional imaging and is of great importance to neuroscience and clinical brain science research. The miniaturized modular design greatly simplifies the complexity of the magnetometer system. The light source module provides resonant pump light with stable power tuning to the D1 spectral absorption line. The sensing module employs a single-beam transverse magnetic field modulation scheme, utilizing a single laser beam for both pumping and detection, enabling simultaneous measurement of two extremely weak magnetic fields in mutually orthogonal transverse directions, significantly reducing optical path complexity. The electronic control module handles temperature control, magnetic field control, and signal acquisition and processing, integrating these functions into a single unit, simplifying the complexity of the electronic system and achieving high integration within a small size.

[0029] like Figure 1 As shown, this invention proposes a miniature modular single-beam dual-axis SERF atomic magnetometer. Through modular design and a single-beam transverse magnetic field modulation scheme, it utilizes a single laser beam for both pumping and detection, enabling simultaneous measurement of two extremely weak magnetic fields in mutually perpendicular transverse directions. This significantly reduces optical path complexity, thus achieving high integration within a small volume. The device consists of three main modules: a light source module, a sensing module, and an electronic control module, greatly simplifying the complexity of the magnetometer system.

[0030] The light source module 1 includes a laser 2, which is responsible for generating resonant lasers that polarize the atomic system. The laser 2 has a built-in saturated absorption frequency stabilization module, which can tune and stabilize the pump light frequency near the D1 spectral absorption line. The light source module 1 also includes a polarization-maintaining fiber 3, which is responsible for guiding the resonant pump light emitted from the laser 2 into the magnetometer probe 6. After alignment, the extinction ratio of the polarization-maintaining fiber 3 can reach more than 30dB, maintaining the stability of the polarization state of the resonant pump light.

[0031] The sensing module 7 is a magnetometer probe 6, such as Figure 2As shown, the internal components include a collimator 5, a polarizer 13, a half-wave plate 14, a polarizing beam splitter 16, a quarter-wave plate 17, an atomic gas cell 20, a miniature three-dimensional flexible coil 18, a heating film 21, and a photodetector 22. The resonant pump light 15, transmitted via the polarization-maintaining fiber 3, is collimated by the collimator 5 and incident along the Z-axis. After passing through the polarizer 13, the pump light 15 becomes linearly polarized light. Subsequently, it passes through the half-wave plate 14 and the polarizing beam splitter 16, becoming a transmitted light beam propagating along the Z-axis and a reflected light beam propagating along the Y-axis. By adjusting the fast axis of the half-wave plate 14, a specific ratio can be achieved between the intensity of the transmitted light and the intensity of the reflected light. The photodetector 22 in front of the gas cell can monitor the magnitude of the light power incident on the gas cell. The transmitted light propagating along the Z-axis is transformed from linearly polarized light into circularly polarized light with a 90-degree phase difference in electric vector after passing through the quarter-wave plate 17. The circularly polarized light tuned to the D1 spectral absorption line can polarize atoms after passing through the heated alkali metal gas cell 20. The polarized atoms are sensitive to the magnetic field. The pump light 15 after passing through the gas cell 20 is received by the photodetector 22 after the gas cell 20. The photodetector 22 converts the pump light intensity signal into a current signal and outputs it through the signal cable 4.

[0032] The alkali metal chamber 20 is the core sensitive element that directly reflects the system characteristics of the magnetometer. It is filled with one of the three alkali metals 19: potassium, rubidium, and cesium, and usually also contains some auxiliary gases. These auxiliary gases affect the efficiency of optical pumping. Inert gases are generally used as buffer gases to suppress collisions between alkali metal atoms and the chamber wall. Collisions between alkali metal atoms 19 and the buffer gas cause depolarization of the atoms. In the chamber 20 with a large optical depth, the probability of photons being reabsorbed increases, the depolarization phenomenon becomes more obvious, and the polarizability of the atomic ensemble is reduced. This effect is called radiative trapping. Quenching gases are usually added to the chamber 20 to suppress this effect, so the chamber 20 is also filled with buffer gas helium and quenching gas nitrogen. The chamber 20 is enclosed by an oven made of a high thermal conductivity material such as aluminum nitride or boron nitride to ensure temperature uniformity within the chamber. There is a heating film 21 on each side of the oven, which can perform high-frequency non-magnetic heating of the chamber 20 to reach the temperature required for atoms to achieve spin-free exchange collisional relaxation (SERF). The platinum resistance thermometer Pt1000 located next to the oven monitors the temperature of the air chamber in real time and transmits the data back to the electronic control module 9, forming a closed-loop mode for real-time PID control of the air chamber temperature.

[0033] The miniature three-dimensional flexible coil 18 is used in the active magnetic compensation system to compensate for residual magnetism and to apply a modulation field to control the atomic ensemble. Since the miniature SERF atomic magnetometer serves practical applications in biomagnetic detection such as cardiac and brain magnetoencephalography, and the magnetic field to be measured is extremely weak, testing in a magnetically shielded environment is necessary. Passive shielding technology involves placing the entire magnetometer system in a magnetically shielded chamber made of multiple layers of high-permeability metallic materials. The magnetically shielded chamber / bucket typically shields the Earth's magnetic field from 50,000 nT to tens of nT before introducing it into the active magnetic field compensation system. Active magnetic field control utilizes a miniature three-dimensional flexible coil 18 to generate or cancel the residual magnetic field of environmental noise. The three-dimensional flexible coil 18 can also apply a rotating modulation field with a specific frequency and amplitude on the xy transverse plane. By applying a high-frequency modulation magnetic field to the sensitive axis, the modulation magnetic field directly drives the precession of atoms and superimposes the weak signal to be measured onto the high-frequency band. By using magnetic field control and combining modulation and demodulation technology, the output signal of the SERF atomic magnetometer near zero magnetic field can be made approximately linear, thereby realizing the measurement of weak magnetic field signals. Although the modulation magnetic field reduces the response of the magnetometer, this method achieves effective suppression of low-frequency noise, increases the signal-to-noise ratio of the detected signal, and thus improves the sensitivity.

[0034] The electronic control module 9 integrates magnetic field control 8, temperature control 10, and signal acquisition and processing 11 into one unit, eliminating the need for some large commercial instruments. It can interact with the light source module 1 and the sensing module 7 via the signal cable 4. The signal cable 4 can transmit power signals to the laser 2 and photodetector 22, and drive signals to the heating film 21 and the micro-sized three-dimensional flexible coil 18.

[0035] The magnetic field control module 8 applies a voltage signal equivalent to DC remanence to the three-dimensional flexible coil 18 via the signal cable 4 to compensate for the environmental remanence; it can also apply amplitude, frequency, and phase signals to regulate the rotation modulation field of atoms for precise control of the atomic ensemble; the temperature control module 10 collects the real-time temperature of the gas chamber via the signal cable 4, and then applies a high-frequency current signal to the heating film 21 to perform non-magnetic high-frequency heating of the gas chamber 20, so that the atomic ensemble is maintained in the SERF state without introducing low-frequency noise for signal detection; the signal acquisition and processing module 11 uses the collected circularly polarized light intensity signal transmitted through the alkali metal gas chamber 20, demodulates it to obtain independent dual-axis magnetic field information, and finally processes and displays the demodulated magnetic field strength data in the host computer 12, and can also apply a calibration signal to verify the magnetometer in real time online.

[0036] The host computer 12 is responsible for comprehensive information monitoring and display of the magnetometer system, as well as sending control commands. The host computer 12 interacts with the light source module 1 via signal cable 4 to adjust and control the intensity and frequency of the resonant pump light. The host computer 12 can collect and display the temperature information of the gas chamber, enabling real-time monitoring of the heating process of the heating film 21. The host computer 12 performs backend processing on the dual-axis magnetic field information collected by the electronic control module 9, calculating and displaying information such as magnetic field strength, sensitivity, and bandwidth.

[0037] like Figure 2 As shown, the photodetector 22 receives the resonant pump light after passing through the alkali metal gas cell 20, converts the light intensity signal of the circularly polarized pump light into a current signal and transmits it to the electronic control module. After demodulation processing by the signal acquisition and processing module of the electronic control module, independent dual-axis magnetic field information is obtained.

[0038] The principle of the miniature modular single-beam dual-axis SERF atomic magnetometer for dual-axis vector magnetic field detection is as follows: two modulated magnetic fields of the same frequency and amplitude with a phase difference of π / 2 are applied simultaneously along the x and y axes, forming a rotating modulation field to manipulate the atomic ensemble. The magnetic field state induced by the atomic ensemble at this time is:

[0039]

[0040] Among them, B x0 B y0 and B z0 It is a triaxial static magnetic field, including remanence and the magnetic field to be measured. and The three-axis magnetic fields are applied along the x-axis and y-axis, respectively. Substituting these three-axis magnetic fields into the classical Bloch equations describing the spin evolution of the atomic ensemble, a set of three-dimensional coupled nonlinear differential equations is obtained. Using series expansion, the perturbation solution under the modulation of the two magnetic fields is obtained, and the first harmonic can be approximated as:

[0041]

[0042] Γ1 is the magnetic resonance linewidth, u is the modulation index, and R... op It is the pumping rate, R rel ω is the relaxation rate, q is the slowing factor, and ω is the modulation frequency. It is the amplitude of the modulated magnetic field along the x-axis, γ e It is the electron gyromagnetic ratio, k z B is an intermediate quantity, Δ is an intermediate quantity. x It is the x-axis magnetic field, B y It is the y-axis magnetic field, B z J1(u) is the z-axis magnetic field, J0(u) is the first-order Bessel function, and J0(u) is the zero-order Bessel function. It is a dual-axis signal output model (alkali metal atomic polarizability) of a miniature modular single-beam dual-axis SERF atomic magnetometer.

[0043] The expression represents the dual-axis signal output model of a miniature modular single-beam dual-axis SERF atomic magnetometer. Due to the π / 2 phase difference between the x and y axis response signals, the signal acquisition and processing module can demodulate and separate the dual-axis signals using a synchronous demodulation method. This transverse rotation modulation scheme features perfectly symmetrical modulation magnetic field parameters, resulting in excellent consistency in the dual-axis magnetic field response, bandwidth, and sensitivity, significantly enhancing the potential for integrating miniature modular single-beam dual-axis SERF atomic magnetometer arrays.

[0044] 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. A miniature modular single-beam biaxial SERF atomic magnetometer, characterized in that, The system includes a light source module integrating a laser, a sensing module integrating a magnetometer probe, and an electronic control module integrating a temperature control module, a magnetic control module, and a signal acquisition and processing module. The electronic control module is connected to the light source module and the sensing module via signal cables. The temperature control module, the magnetic control module, and the signal acquisition and processing module are all connected to a host computer. The resonant pump light emitted from the laser is guided into the magnetometer probe through a polarization-maintaining fiber. The resonant pump light polarizes the alkali metal atoms in the gas chamber of the sensing module and is then emitted from the gas chamber into a photodetector, forming independent biaxial magnetic field information with a phase difference of π / 2. The signal acquisition and processing module demodulates and separates the biaxial signal from the biaxial magnetic field information using a synchronous demodulation method and outputs it to the host computer.

2. The miniature modular single-beam biaxial SERF atomic magnetometer according to claim 1, characterized in that, The magnetometer probe includes a collimator, a polarizer, a half-wave plate, and a polarizing beam splitter connected in sequence. The collimator is connected to the laser via a polarization-maintaining fiber. The transmission side of the polarizing beam splitter is connected to a first photodetector via a quarter-wave plate and a gas cell. The reflection side of the polarizing beam splitter is connected to a second photodetector. The gas cell is enclosed by an oven made of aluminum nitride or boron nitride. There is a heating film on each side of the oven to perform high-frequency non-magnetic heating of the gas cell. The oven is located inside a miniature three-dimensional flexible coil. A platinum resistance thermometer (Pt1000) close to the oven monitors the temperature of the gas cell in real time and transmits the data back to the electronic control module to form a closed-loop mode for real-time PID control of the gas cell temperature. The miniature three-dimensional flexible coil is used to apply a rotational modulation field in the xy transverse plane to manipulate the atomic ensemble.

3. The miniature modular single-beam biaxial SERF atomic magnetometer according to claim 1, characterized in that, The chamber is filled with one of three alkali metals: potassium, rubidium, and cesium. The chamber is also filled with buffer gas helium and quenching gas nitrogen.

4. The miniature modular single-beam biaxial SERF atomic magnetometer according to claim 1, characterized in that, The resonant pump light emitted by the laser is a resonant pump light whose power is stably tuned to the D1 spectral absorption line.

5. The miniature modular single-beam biaxial SERF atomic magnetometer according to claim 2, characterized in that, The micro-miniature three-dimensional flexible coils apply x-axis modulated magnetic fields respectively. and y-axis modulated magnetic field and All are amplitudes, ω is frequency, and t is time.

6. The miniature modular single-beam biaxial SERF atomic magnetometer according to claim 5, characterized in that, The expression for the magnetic field B induced by the atomic ensemble is as follows: Among them B x0 It is the static magnetic field along the x-axis, B y0 It is the static magnetic field along the y-axis, B z0 It is the static magnetic field along the z-axis.

7. The miniature modular single-beam biaxial SERF atomic magnetometer according to claim 2, characterized in that, The ratio of transmitted light intensity to reflected light intensity is adjusted by adjusting the fast axis of the half-wave plate, and the magnitude of the light power in front of the incident gas chamber is monitored by the second photodetector.

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