Array optical pump magnetometer system based on thin film light splitting technology and magnetic field precision measurement method thereof

Abstract

The invention discloses an array optical pump magnetometer system based on a thin film light splitting technology and a magnetic field precision measurement method thereof, and the system comprises a laser emission source, a 1 / 2 slide, a plurality of thin film light splitting sheets, a total reflection mirror, a 1 / 4 slide, a radio frequency coil, a gas chamber array and a photoelectric detector array. A 1 / 2 slide, a plurality of film light splitting sheets with customized proportions and a total reflection mirror are sequentially arranged on a laser light path emitted by the laser emission source; each thin film beam splitter is arranged on a laser light path in an inclined manner of 45 degrees, so that incident laser and the thin film beam splitters are incident at 45 degrees, and transmission and reflection are perpendicular to each other; the film beam splitter comprises a transparent glass substrate, a beam splitting film and an antireflection film, the two sides of the transparent glass substrate are provided with the beam splitting film and the antireflection film respectively, and the beam splitting film (31) is arranged on the side close to incident laser; the plurality of thin film beam splitters are sequentially arranged in a manner that the reflection transmittance is (1: N-1), (1: N-2), (1: N-3)..., and are used for splitting incident laser into N paths of laser with the same characteristics;

Description

Technical Field

[0001] The present invention belongs to the technical field of magnetic field precision measurement, and in particular relates to an array optical pump magnetometer system based on thin film spectrometry technology and a magnetic field precision measurement method thereof. Background Art

[0002] As an important support for the quantum information industry, quantum precision measurement technology is becoming more and more common in various fields. Laser optically pumped magnetometer technology has become practical. Its ultra-high detection sensitivity can meet new demands in various fields, especially highly consistent multi-channel magnetic detection solutions. It can simultaneously obtain spatial and temporal information of the magnetic field to meet the detection needs in high-precision fields.

[0003] The magnetic field is a vector field and contains spatial information. Optically pumped magnetometers are widely used in fields such as geomagnetic field detection, biomagnetic field detection, and material testing. Multiple optically pumped magnetometers are used to form a detection array to simultaneously obtain the temporal and spatial information of the magnetic field. The array magnetometer system can realize spatial magnetic field detection, obtaining magnetic field information of multiple spatial points in a single measurement, and the spatial measurement width can reach tens of centimeters. In the industrial field, this technology is used for magnetic material testing and non-destructive testing. In the biomedical field, this technology can be used to detect the distribution of magnetic nanoparticles and can also be used for human magnetocardiography. The array detection system can greatly shorten the detection time, improve the detection efficiency, and obtain spatial dimension information. In the array magnetometer, the parameters of each laser must be consistent, including the laser wavelength, optical power, polarization, propagation direction and other parameters. Only in this way can the working state of each magnetometer be consistent and the measurement results are more accurate.

[0004] The existing array magnetometer uses a multi-channel laser, fiber optic splitter, and lens splitter solution to form a system. Since the magnetometer system has strict requirements on the intensity and polarization of the laser, the deviation of the intensity and polarization direction between the multiple lasers is small, and the multiple beams of light after splitting are parallel to each other and the spacing is controllable. It is difficult for the existing technology to take all the requirements into account. In addition, the existing technology uses multiple lasers as light sources to build the entire system. This solution will greatly increase the difficulty and cost of adjustment. The working parameters of each laser are inconsistent, and it is difficult to ensure the consistency of the parameters of the output laser, which in turn affects the performance of the system. The existing fiber optic beam splitter can split the laser into multiple channels and then form a multi-channel magnetometer system, but the fiber optic splitter system cannot stably output lasers with constant light intensity and polarization. The relevant parameters will change with changes in vibration and ambient temperature. The jitter of polarization and light intensity affects the signal quality, thereby affecting the final magnetic field measurement accuracy. The existing polarization beam splitting prism and half glass slide can realize multi-channel laser beam splitting, but in the array system design, the polarization beam splitting prism is bulky, difficult to adjust, expensive, and difficult to integrate. Figure 1The four-way beamsplitting system shown requires three polarizing beamsplitter prisms, three half-glass slides, and two reflectors for a total of eight lenses. This makes multi-way system design very complex and requires adjustment, making it only suitable for desktop magnetic field testing experiments. Non-polarizing beamsplitter prisms can split laser beams, but they require natural or circularly polarized light for optimal performance. However, manufacturing defects can alter laser polarization, leading to strong light absorption and a low beam splitting ratio. This high cost makes it unsuitable for mass production, as the effects of polarization and light intensity can lead to poor consistency in the magnetic field measurement subsystem. Summary of the Invention

[0005] To address the technical issues of existing multi-channel magnetometers for measuring magnetic fields, such as high cost, large size, and limited application, the present invention provides an array optically pumped magnetometer system based on thin-film spectrometry technology and a method for precisely measuring magnetic fields. This system features a simple structure, high stability, compact size, high reliability, low cost, and high consistency. It utilizes a simple, low-cost thin-film lens assembly to split incident laser light into multiple parallel laser beams with consistent intensity and polarization. These laser beams with consistent parameters generate a multi-channel magnetometer system. This system saves costs and facilitates industrial mass production. Furthermore, the high consistency of the laser beams in each sub-optical path facilitates consistent magnetic field detection sensitivity across each sub-channel.

[0006] The technical solution adopted in the present invention is:

[0007] The first aspect of the present invention relates to an array optical pump magnetometer system based on thin film spectrometry technology, characterized in that it comprises a laser emission source (1), a 1 / 2 glass slide (2), several thin film spectrometers (3), a total reflection mirror (4), a 1 / 4 glass slide (5), a radio frequency coil (6), an air chamber array (7) and a photodetector array (8), wherein the laser light path emitted by the laser emission source (1) is sequentially provided with a 1 / 2 glass slide (2), several thin film spectrometers (3) with customized ratios and a total reflection mirror (4); and below the several thin film spectrometers (3) with customized ratios and the total reflection mirror (4) are correspondingly provided with a 1 / 4 glass slide (5), a radio frequency coil (6), an air chamber array (7) and a photodetector array (8);

[0008] Each of the thin film beam splitters (3) is arranged on the laser light path at an angle of 45 degrees to ensure that the incident laser is incident at a 45-degree angle to the thin film beam splitter (3) so that transmission and reflection are perpendicular to each other;

[0009] The thin film beam splitter (3) comprises a transparent glass substrate (31), a beam splitter film (32) and an anti-reflection film (33), wherein the beam splitter film (32) and the anti-reflection film (33) are respectively arranged on both sides of the transparent glass substrate (31), and the beam splitter film (31) is arranged on the side close to the incident laser (1), and the transparent glass substrate (31) is made of K9 glass or other optical glass, and has a thickness of 0.5 mm or other thinner thickness;

[0010] Several thin film beam splitters (3) are sequentially set to have reflection and transmittance ratios of (1:N-1), (1:N-2), (1:N-3) ..., so as to split the incident laser into N paths of laser light with the same characteristics.

[0011] Furthermore, the material of the beam splitter film (32) is selected according to the wavelength of the incident laser. The beam splitter film material is selected from magnesium fluoride (MgF2), silicon dioxide (SiO2) or titanium dioxide (TiO2) to adjust the beam splitter's reflective transmittance to the incident light, thereby achieving different transmittance and reflectance ratios of the lens to the laser.

[0012] Furthermore, the thin film beam splitter (3) is made by utilizing the different reflection and transmission ratios of the reflective film for the S wave and P wave of polarized light. The polarization direction of the incident light is required to be fixed. The thin film beam splitter can split the laser beam according to the set ratio and apply it to various subsystems.

[0013] Furthermore, the dichroic film (32) is alternately coated with high-refractive-index and low-refractive-index materials to form a multilayer film structure, and the ratio of reflection and refraction is achieved by using multilayer films and different film layer thicknesses.

[0014] Furthermore, the spacing between adjacent thin film beam splitters and the spacing between the thin film beam splitter (3) and the total reflection mirror (4) are both L, and can be changed according to actual detection requirements.

[0015] Furthermore, the distance L is preferably 1-10 cm.

[0016] A second aspect of the present invention relates to a method for precisely measuring a magnetic field in an array optically pumped magnetometer system, characterized in that it comprises the following steps:

[0017] S1. A beam of linearly polarized light emitted through an optical fiber or laser is used. After adjusting the polarization direction of the incident light, it enters a thin film beam splitter system. The thin film beam splitter system consists of several thin film beam splitters with customized ratios and a total reflection mirror. The incident light passes through a 1 / 2 glass slide, several thin film beam splitters, and a total reflection mirror in sequence. The incident light is divided into N parts. The incident light divided into N parts has basically the same optical power, the same polarization direction, and the same propagation direction.

[0018] S2, the incident light divided into N parts passes through a quarter glass slide and becomes a circularly polarized light array;

[0019] S3, circularly polarized light enters the gas cell array and interacts with the alkali metal atoms to generate light polarization. The polarized alkali metal atoms generate macroscopic magnetic moments, which interact with the radio frequency generated by the radio frequency coils set on both sides of the gas cell array. The resulting light signal is received by the photodiode;

[0020] S4. Inferring the magnitude of the external magnetic field based on the frequency of the radio frequency signal to achieve magnetic field measurement.

[0021] Furthermore, in step S3, atoms are used to produce the Zeeman effect in the magnetic field, and the atomic energy levels are split. The magnetic field value can be obtained by detecting the spacing of the Zeeman energy levels, including: first, the atoms are polarized by the strong pumping effect of the laser, and then the atoms are excited by radio frequency. When the radio frequency frequency is consistent with the frequency of the Zeeman sub-level of the magnetic field, the polarized atoms absorb the radio frequency signal to produce a resonance effect, thereby detecting the current magnetic field.

[0022] Furthermore, the specific method of the interaction between the circularly polarized light and the alkali metal atoms described in step S3 is: the alkali metal atoms and the buffer gas are filled into the glass gas chamber, the split laser enters the gas chamber and interacts with the atoms to polarize the atoms, the radio frequency coil generates a radio frequency signal, and when the frequency of the radio frequency coil is consistent with the frequency corresponding to the atomic Zeeman sub-energy level, the effect of the laser on the alkali metal atoms is the strongest, and the current magnetic field size is inferred based on the frequency of the radio frequency coil.

[0023] Furthermore, the coating method adopts vacuum coating technology, namely electron beam evaporation or magnetron sputtering technology; including: evenly depositing the film material on the glass surface, accurately controlling the thickness of each layer of film, and ensuring that the optical thickness meets the design requirements.

[0024] Furthermore, in step S1, according to the N-way splitting, reflection and transmittance ratios of (1:N-1), (1:N-2), (1:N-3)... are respectively produced. The last piece uses a total reflection mirror to form a spectrometer system, so that the incident laser can be divided into N-way lasers with the same characteristics.

[0025] Compared with the prior art, the beneficial effects of the present invention are embodied in:

[0026] 1. The present invention has a simple structure, no need for adjustment, high stability, small size, high reliability, low cost, and high consistency. It uses a simple low-cost thin film lens group to split the incident laser into multiple parallel laser beams with consistent light intensity and polarization, and uses laser beams with consistent parameters to generate a multi-channel magnetometer system.

[0027] 2. The present invention saves costs and is convenient for industrial mass production. At the same time, since the laser consistency of each sub-optical path is high, it is conducive to the consistency of the magnetic field detection sensitivity of each sub-channel;

[0028] 3. In the multi-channel magnetic detection system of the present invention, background magnetic noise is mixed with the target magnetic signal. If the consistency of the sub-channels is high, it means that their common-mode noise is low. The data of the sub-channels can be used to eliminate the background noise and common-mode noise, thereby improving the detection response sensitivity to the target object's magnetic field.

[0029] 4. The present invention is flexible and variable, has a small size, requires fewer optical components, and is low in price. The number of sub-channels can be increased and the detection distance of the sub-channels can be adjusted according to design requirements, and it can be applied to various occasions.

[0030] 5. The present invention has only one laser light source. It is only necessary to adjust the working parameters of the total light source, such as laser wavelength, laser power, and laser polarization. The lasers in each sub-light path do not need to be adjusted. Compared with the magnetometer array system composed of N independent lasers, the laser adjustment of this system is more convenient and has high consistency. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a schematic diagram of a traditional 4-way array magnetometer system.

[0032] Figure 2 It is a schematic diagram of the 4-way array spectroscopic magnetometer system in the present invention.

[0033] Figure 3 Schematic diagram of the beam splitter film of the present invention.

[0034] Figure 4a 、 Figure 4b and Figure 4c They are respectively the simulation results of using different customized spectroscopic films of the present invention. DETAILED DESCRIPTION

[0035] The following describes the specific implementation of the embodiment of the present invention in detail with reference to the accompanying drawings. It should be understood that the specific implementation described herein is only used to illustrate and explain the embodiment of the present invention and is not used to limit the embodiment of the present invention.

[0036] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0037] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with exemplary embodiments.

[0038] Example 1

[0039] refer to Figure 2 and Figure 3The present invention provides an array optical pump magnetometer system based on thin film spectrometry technology, comprising a laser emission source (1), a 1 / 2 glass plate (2), a plurality of thin film spectrometers (3), a total reflection mirror (4), a 1 / 4 glass plate (5), a radio frequency coil (6), an air chamber array (7), and a photodetector array (8). The laser light path emitted by the laser emission source (1) is sequentially provided with a 1 / 2 glass plate (2), a plurality of thin film spectrometers (3) with customized ratios, and a total reflection mirror (4); and a 1 / 4 glass plate (5), a radio frequency coil (6), an air chamber array (7), and a photodetector array (8) are correspondingly provided below the plurality of thin film spectrometers (3) with customized ratios and the total reflection mirror (4).

[0040] Each of the thin film beam splitters (3) is arranged on the laser light path at an angle of 45 degrees to ensure that the incident laser is incident at a 45-degree angle to the thin film beam splitter (3) so that transmission and reflection are perpendicular to each other;

[0041] The thin film beam splitter (3) comprises a transparent glass substrate (31), a beam splitter film (32) and an anti-reflection film (33), wherein the beam splitter film (32) and the anti-reflection film (33) are respectively provided on both sides of the transparent glass substrate (31), and the beam splitter film (31) is provided on a side close to the incident laser (1);

[0042] Several thin film beam splitters (3) are sequentially set to have reflection and transmittance ratios of (1:N-1), (1:N-2), (1:N-3) ..., so as to split the incident laser into N paths of laser light with the same characteristics.

[0043] In this embodiment, the material of the beam splitter film (32) is selected according to the wavelength of the incident laser. The beam splitter film material is selected from magnesium fluoride (MgF2), silicon dioxide (SiO2) or titanium dioxide (TiO2) to adjust the beam splitter's reflection transmittance to the incident light, thereby achieving different transmission and reflection ratios of the lens to the laser.

[0044] In this embodiment, the thin film beam splitter (3) is made by utilizing the different reflection and transmission ratios of the reflective film for the S wave and P wave of polarized light. The polarization direction of the incident light is required to be fixed. The thin film beam splitter can split the laser beam according to the set ratio and apply it to various subsystems.

[0045] In this embodiment, the dichroic film (32) is formed by alternately coating high refractive index and low refractive index materials to form a multilayer film structure, and the ratio of reflection and refraction is achieved by using multiple layers and different film thicknesses. Specifically, a few to more than ten layers can usually meet the requirements.

[0046] In this embodiment, the dichroic film (32) uses a K9 glass substrate with a diameter of 1 cm and a thickness of 0.5 mm. If the glass substrate is too thick, a certain lateral displacement will occur due to light refraction, thereby causing changes in the spacing or parallelism of the sub-light paths. If the glass is too thin, the structural strength cannot be guaranteed. The thickness is preferably between 0.2-1 mm.

[0047] In this embodiment, the spacing between adjacent thin film beam splitters and the spacing between the thin film beam splitter (3) and the total reflection mirror (4) are both L, and the spacing L is preferably 1-10 cm. The array spacing L can be changed according to actual detection needs by appropriately adjusting the spacing between each beam splitter. The spatial resolution of the array system can be changed according to the needs of the actual scene.

[0048] In this embodiment, the coating method adopts vacuum coating technology, namely electron beam evaporation or magnetron sputtering technology; including: uniformly depositing the film layer material on the glass surface, accurately controlling the thickness of each film layer, and ensuring that the optical thickness meets the design requirements.

[0049] Design of spectroscopic system membrane Figure 3 As shown in the figure, the incident surface is the designed spectroscopic film, and an anti-reflection film is added to the transmission surface to improve the light transmittance. In a one-to-four system, three types of films need to be designed in the spectroscopic system, with transmission / reflection ratios of 3:1, 2:1, and 1:1, plus a universal total reflection mirror to form the spectroscopic system (as shown in Table 1). The film layer uses a combination of multilayer titanium dioxide and silicon dioxide. Within the range of about 50nm around the working wavelength of 795nm, it can maintain the design indicators and avoid errors caused by dispersion and assembly accuracy. The simulation results are shown in the figure. Figure 4a 、 4b and 4c.

[0050] Table 1 Customized reflective film design

[0051]

[0052] Example 2

[0053] The method for accurately measuring a magnetic field using the array optical pump magnetometer system of Example 1 includes the following steps:

[0054] S1. A beam of linearly polarized light emitted through an optical fiber or laser is used. After adjusting the polarization direction of the incident light, it enters a thin-film beam splitter system. The thin-film beam splitter system consists of several thin-film beam splitters with customized ratios and a total reflection mirror. The incident light passes through a 1 / 2 glass slide, several thin-film beam splitters, and a total reflection mirror in sequence. The incident light is divided into N parts. The optical power of the N parts of the incident light is basically the same, and the polarization direction and propagation direction are the same.

[0055] S2, the incident light divided into N parts passes through a quarter glass slide and becomes a circularly polarized light array;

[0056] S3, circularly polarized light enters the gas cell array and interacts with the alkali metal atoms to generate light polarization. The polarized alkali metal atoms generate macroscopic magnetic moments, which interact with the radio frequency generated by the radio frequency coils set on both sides of the gas cell array. The resulting light signal is received by the photodiode;

[0057] S4. Inferring the magnitude of the external magnetic field based on the frequency of the radio frequency signal to achieve magnetic field measurement.

[0058] Specifically, in step S3, atoms are used to generate the Zeeman effect in a magnetic field, and the atomic energy levels are split. The magnetic field value can be obtained by detecting the spacing of the Zeeman energy levels, including: first, the atoms are polarized using the strong pumping effect of the laser, and then the atoms are excited using radio frequency. When the radio frequency frequency is consistent with the frequency of the Zeeman sub-level of the magnetic field, the polarized atoms absorb the radio frequency signal to produce a resonance effect, thereby detecting the current magnetic field.

[0059] Specifically, the specific method for the interaction between the circularly polarized light and the alkali metal atoms described in step S3 is: alkali metal atoms and buffer gas are filled into a glass gas chamber, the split laser enters the gas chamber and interacts with the atoms to polarize the atoms, the radio frequency coil generates a radio frequency signal, when the frequency of the radio frequency coil is consistent with the frequency corresponding to the atomic Zeeman sub-energy level, the effect of the laser on the alkali metal atoms is strongest, and the current magnetic field size is inferred based on the frequency of the radio frequency coil.

[0060] Specifically, alkali metal atoms such as potassium, rubidium, and cesium atoms are generally selected as working substances, inert gases such as nitrogen, helium, and neon are selected as buffer gases for the atoms, and lasers with wavelengths corresponding to the D1 line of alkali metal atoms are selected as the total light source.

[0061] Specifically, in step S1, according to the N-way splitting, reflection and transmittance ratios of (1:N-1), (1:N-2), (1:N-3)... are respectively produced. The last piece uses a total reflection mirror to form a spectrometer system, so that the incident laser can be divided into N-way lasers with the same characteristics.

[0062] Specifically, in this embodiment, rubidium atoms are used as the working material, and their corresponding D1 line transition wavelength is around 795nm. Based on this wavelength, the lenses required for the spectroscopic system are designed. A one-to-four optical system is planned, resulting in a four-way optical pumping magnetometer. A laser generates a 795nm laser beam with a spot diameter of approximately 5mm. The laser's polarization plane is modulated to S polarization by a half-glass slide. The laser beam is aligned with three beamsplitters and a total reflection mirror. The lenses are made of a 1cm diameter, 0.5mm thick, circular K9 glass substrate coated with a film. They are mounted 4cm apart, with a spatial measurement width of 16cm. The laser beam forms a 45° angle with the beamsplitters. The first beamsplitter has a splitting ratio of 3:1, the second has a splitting ratio of 2:1, and the third has a splitting ratio of 1:1. The fourth lens is a universal total reflection mirror. This produces four 795nm laser beams with equal intensity and polarization characteristics consistent with the incident laser.

[0063] Magnetic field detection uses a common optically pumped magnetometer scheme. Split laser light is converted into circularly polarized light by passing it through a quarter-glass slide. Rubidium vapor and 200 torr nitrogen are placed in an atomic chamber measuring 2 x 2 x 2 cm. The laser light passes through the chamber and is ultimately received by a photodetector. An RF signal is injected into the RF coil. When the RF signal's frequency matches the Larmor precession frequency corresponding to the magnetic field, magnetic resonance occurs. The magnitude of the external magnetic field is determined based on the RF signal's frequency. The spacing of the atomic chamber array matches the laser's spacing, both at 4 cm. A pair of RF coils surround each chamber to excite the atoms. After passing through the chamber, the laser light is received by a photodetector.

[0064] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. An array optical pump magnetometer system based on thin film spectrometry technology, characterized by: The invention comprises a laser emission source (1), a 1 / 2 glass plate (2), several thin film beam splitters (3), a total reflection mirror (4), a 1 / 4 glass plate (5), a radio frequency coil (6), an air chamber array (7), and a photodetector array (8); the 1 / 2 glass plate (2), several thin film beam splitters (3) with customized proportions, and a total reflection mirror (4) are sequentially arranged on the laser light path emitted by the laser emission source (1); and the 1 / 4 glass plate (5), the radio frequency coil (6), the air chamber array (7), and the photodetector array (8) are correspondingly arranged below the several thin film beam splitters (3) with customized proportions and the total reflection mirror (4); Each of the thin film beam splitters (3) is arranged on the laser light path at an angle of 45 degrees to ensure that the incident laser is incident at a 45-degree angle to the thin film beam splitter (3) so that transmission and reflection are perpendicular to each other; The thin film beam splitter (3) comprises a transparent glass substrate (31), a beam splitter film (32) and an anti-reflection film (33), wherein the beam splitter film (32) and the anti-reflection film (33) are respectively provided on both sides of the transparent glass substrate (31), and the beam splitter film (31) is provided on a side close to the incident laser (1); Several thin film beam splitters (3) are sequentially set to have reflection and transmittance ratios of (1:N-1), (1:N-2), (1:N-3) ..., so as to split the incident laser into N paths of laser light with the same characteristics.

2. The array optical pump magnetometer system based on thin film spectrometry technology according to claim 1, characterized in that: The material of the beam splitter film (32) is selected according to the wavelength of the incident laser. The beam splitter film material is selected from magnesium fluoride (MgF2), silicon dioxide (SiO2) or titanium dioxide (TiO2) to adjust the beam splitter's reflection transmittance to the incident light, thereby achieving different transmission and reflection ratios of the lens to the laser.

3. The array optical pump magnetometer system based on thin film spectrometry technology according to claim 1, characterized in that: The thin film beam splitter (3) is made by utilizing the different reflection and transmission ratios of the reflective film for the S wave and P wave of polarized light. The polarization direction of the incident light is required to be fixed. The thin film beam splitter can split the laser beam according to the set ratio and apply it to various subsystems.

4. The array optical pump magnetometer system based on thin film spectrometry technology according to claim 1, characterized in that: The beam splitting film (32) is alternately coated with high refractive index materials and low refractive index materials to form a multilayer film structure, and the ratio of reflection and refraction is achieved by using the multilayer film and different film layer thicknesses.

5. The array optical pump magnetometer system based on thin film spectrometry technology according to claim 1, characterized in that: The spacing between adjacent thin film beam splitters and the spacing between the thin film beam splitter (3) and the total reflection mirror (4) are both L, and can be changed according to actual detection requirements.

6. A method for precisely measuring the magnetic field of an array optically pumped magnetometer system, characterized in that: The steps include: S1. A beam of linearly polarized light emitted through an optical fiber or laser is used. After adjusting the polarization direction of the incident light, it enters a thin film beam splitter system. The thin film beam splitter system consists of several thin film beam splitters with customized ratios and a total reflection mirror. The incident light passes through a 1 / 2 glass slide, several thin film beam splitters, and a total reflection mirror in sequence. The incident light is divided into N parts. The incident light divided into N parts has basically the same optical power, the same polarization direction, and the same propagation direction. S2, the incident light divided into N parts passes through a quarter glass slide and becomes a circularly polarized light array; S3, circularly polarized light enters the gas cell array and interacts with the alkali metal atoms to generate light polarization. The polarized alkali metal atoms generate macroscopic magnetic moments, which interact with the radio frequency generated by the radio frequency coils set on both sides of the gas cell array. The resulting light signal is received by the photodiode; S4. Inferring the magnitude of the external magnetic field based on the frequency of the radio frequency signal to achieve magnetic field measurement.

7. The method for precisely measuring the magnetic field of an array optical pumping magnetometer system according to claim 6, characterized in that: In step S3, atoms are used to generate the Zeeman effect in a magnetic field, and the atomic energy levels are split. The magnetic field value can be obtained by detecting the spacing of the Zeeman energy levels, including: first, the atoms are polarized using the strong pumping effect of the laser, and then the atoms are excited using radio frequency. When the radio frequency frequency is consistent with the frequency of the Zeeman sub-level of the magnetic field, the polarized atoms absorb the radio frequency signal to produce a resonance effect, thereby detecting the current magnetic field.

8. The method for precise magnetic field measurement of an array optical pumping magnetometer system according to claim 6, characterized in that: The specific method of the interaction between the circularly polarized light and the alkali metal atoms described in step S3 is: alkali metal atoms and buffer gas are filled into a glass gas chamber, the split laser enters the gas chamber and interacts with the atoms to polarize the atoms, the radio frequency coil generates a radio frequency signal, when the frequency of the radio frequency coil is consistent with the frequency corresponding to the atomic Zeeman sub-energy level, the effect of the laser on the alkali metal atoms is strongest, and the current magnetic field size is inferred based on the frequency of the radio frequency coil.

9. The method for precise magnetic field measurement of an array optical pumping magnetometer system according to claim 6, characterized in that: The coating method uses vacuum coating technology, namely electron beam evaporation or magnetron sputtering technology; including: evenly depositing the film material on the glass surface, precisely controlling the thickness of each layer of film to ensure that the optical thickness meets the design requirements.

10. The method for precise magnetic field measurement of an array optical pumping magnetometer system according to claim 6, characterized in that: In step S1, according to the N-way splitting, reflection and transmittance ratios of (1:N-1), (1:N-2), (1:N-3)... are produced respectively. The last piece uses a total reflection mirror to form a spectrometer system, so that the incident laser can be divided into N-way lasers with the same characteristics.

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