A chip faraday active optical clock and a method for implementing the same

Abstract

The application discloses a chip Faraday active optical clock and an implementation method thereof. The application comprises a semiconductor laser diode, a base wafer, a cover wafer, wherein the base wafer is provided with a cavity wafer, the cavity wafer is provided with a first polarization light splitting prism, a second polarization light splitting prism, a MEMS alkali metal atom gas chamber and an active optical clock resonant cavity mirror, the cavity wafer is connected with the cover wafer to form a closed cavity; the semiconductor laser diode outputs a wide spectrum fluorescent signal which is transmitted to the first polarization light splitting prism through the base wafer and is divided into two beams, one of which enters the atom gas chamber to realize frequency locking; the second polarization light splitting prism divides the laser output by the atom gas chamber into two beams, one of which is used as the laser output of the chip Faraday active optical clock, and the other of which is incident to the active optical clock resonant cavity mirror; the active optical clock resonant cavity mirror reflects part of the incident laser back to the diode to realize continuous oscillation of the laser; wherein the chip Faraday active optical clock works in a bad cavity region.

Description

Technical Field

[0001] This invention belongs to the field of atomic clock and quantum frequency standard technology, specifically relating to a chip-based Faraday active optical clock and its implementation method. Background Technology

[0002] Active optical clocks, a type of high-potential laser source or quantum frequency standard that stores coherence in atomic dipoles rather than traditional resonant cavities, hold considerable research potential in cavity quantum electrodynamics, novel atomic clocks, laser physics, and quantum manipulation. With the rise of the active optical clock concept, superradiative active optical clock lasers implemented using methods such as hot atom gas cells, hot atom beams, moving magneto-optical traps, and moving optical lattices have demonstrated their theoretical advantages, achieving substantial theoretical and experimental verification in surpassing the Scholl-Towns quantum linewidth limit. However, these methods require complex steps to obtain the pump source and atomic system. For cold atom schemes, multiple laser systems are needed for atomic laser cooling and trapping, and continuous output is difficult to achieve. For ultra-narrow linewidth quantum transition schemes, high-precision resonant cavities are required for optical feedback, increasing system complexity and environmental interference resistance. Therefore, further breakthroughs are needed in the practical application, miniaturization, and continuous operation of active optical clocks. How to practicalize active optical clocks, which have extremely high potential in linewidth and frequency stability and are expected to become the next generation of novel optical clocks, is an urgent problem to be solved.

[0003] In summary, the core issue addressed by this invention is to find new methods to solve the problems of practical application, miniaturization, and continuous operation of active optical clocks, and to improve the performance of existing passive atomic clocks and expand their application scope. Summary of the Invention

[0004] To address the aforementioned problems, the present invention aims to provide a chip-based Faraday active optical clock and its implementation method. The present invention employs a chip-based Faraday active optical clock implementation scheme, which integrates a high-gain semiconductor medium and a micro-atomic filter based on a MEMS atomic gas cell. This achieves bad cavity laser oscillation on a chip-integrated scale, with the gain bandwidth limited within the atomic Doppler broadening line, equal to the transmission spectrum bandwidth of the atomic filter. The chip-based structure and specific cavity mirror design significantly enhance the cavity attenuation rate, i.e., the cavity mode linewidth, enabling the chip-based Faraday active optical clock to operate in the bad cavity region, fully leveraging the narrow linewidth and cavity pull suppression advantages of active optical clocks.

[0005] This invention enables a chip-scale Faraday active optical clock with a linewidth much smaller than the Scholl-Townes quantum limit linewidth of a good-cavity Faraday laser. By adjusting the atomic number density of a MEMS atomic filter to change the transmission spectrum, it is equivalent to directly adjusting the gain attenuation rate Γ, thereby changing the bad cavity coefficient. By studying the relationship between the cavity pulling suppression coefficient and the ratio of κ and Γ, the invention theoretically analyzes and experimentally verifies the changes in the Scholl-Townes quantum limit linewidth under different degrees of cavity pulling suppression, seeking optimal parameters to explore the experimentally achievable limit linewidth of the Faraday active optical clock. Active optical clocks are a major direction for the future development of atomic clocks and an effective way to achieve sub-natural linewidth superradiative lasers. The chip-scale Faraday active optical clock proposed in this invention is an important solution to the challenges of practical application, miniaturization, and continuous operation of active optical clocks.

[0006] This scheme has four innovative points and advantages: ① Separation of the gain and frequency selection devices reduces interference from frequency selection on the gain, and the semiconductor gain is larger, making it easier to achieve laser oscillation; ② By adjusting the transmission spectrum bandwidth of the frequency selection device through temperature adjustment, the ratio of gain bandwidth to cavity mode bandwidth can be continuously adjusted, thereby continuously adjusting the bad cavity coefficient; ③ MEMS integration achieves a smaller volume, which can improve the cavity attenuation rate, allowing the laser to operate in the bad cavity region, and greatly improve the practicality of the system; ④ By adjusting the bad cavity coefficient, the cavity attenuation rate can be adjusted, thereby achieving the purpose of adjusting the laser linewidth. The bad cavity coefficient = cavity mode linewidth ÷ gain linewidth. When the cavity length of the MEMS-integrated Faraday laser is determined, i.e., the cavity mode linewidth is determined, the bad cavity coefficient can be changed simply by changing the gas chamber temperature and thus the gain linewidth. Different bad cavity coefficients result in different cavity pulling suppression effects.

[0007] One object of the present invention is to provide a chip-based Faraday active optical clock, which includes: a semiconductor laser diode, a first polarizing beam splitter prism, a MEMS alkali metal atom gas cell, a second polarizing beam splitter prism, a first permanent magnet, a second permanent magnet, an active optical clock resonant cavity mirror, a substrate wafer, a cavity wafer, a cover wafer, a first solder sheet, a second solder sheet, and a getter.

[0008] Among them, the semiconductor laser diode serves as the gain medium of the chip-based Faraday active optical clock, outputting a broadband fluorescence signal. The center wavelength is related to the type of atomic transition in the atomic filter, including but not limited to 767nm, 770nm, 780nm, 795nm, 852nm, and 894nm, which correspond to the D2 and D1 transition lines of potassium, rubidium, and cesium atoms, respectively. The quantum well materials for different wavelengths are different, such as GaAs and InGaAs. The semiconductor laser diode has an FP cavity structure with high reflectivity at the rear cavity surface and high transmittance at the front cavity surface to prevent the generation of internal cavity modes.

[0009] The polarization directions of the first polarizing beam splitter and the second polarizing beam splitter are perpendicular; the material chosen is K9 glass (optical borosilicate glass);

[0010] MEMS alkali metal atom gas cells selectively transmit incident fluorescence signals, enabling laser transmission at the aforementioned wavelengths. These cells can be filled with potassium, rubidium, and potassium atoms. Each aperture is metal-plated and connected to four electrode pins to heat the cell, increasing the atomic number density and controlling the temperature. To achieve good frequency selectivity and transmittance, the cell is typically heated to 100°C. High borosilicate glass or silicon is chosen as the material for high transmittance of light at wavelengths of 767nm, 770nm, 780nm, 795nm, 852nm, and 894nm, corresponding to the D2 and D1 transition lines of potassium, rubidium, and cesium atoms, respectively.

[0011] The first and second permanent magnets are used to generate a uniform magnetic field along the direction of light propagation in the gas chamber.

[0012] The first polarizing beam splitter, the second polarizing beam splitter, the MEMS alkali metal atom gas cell, the first permanent magnet, and the second permanent magnet together form a Faraday atom filter, which achieves frequency-selective filtering of broadband fluorescence signals. At the same time, the transmission bandwidth of this Faraday atom filter directly determines the gain attenuation rate Γ, which is generally 2π×1GHz. Only light with transition frequencies near the atomic resonance frequency can achieve polarization direction rotation and be output from the second polarizing beam splitter.

[0013] An active optical clock resonator mirror is used to achieve optical feedback. The mirror does not need to have a very high reflectivity, thereby increasing the cavity attenuation rate κ. κ is jointly determined by the mirror reflectivity and the transmittance of the Faraday atom filter. By changing the reflectivity parameters of the Faraday atom filter and the mirror to make κ > Γ, the laser operates in the bad cavity region. The material chosen is ULE glass (zero expansion glass, titanium dioxide-silicate glass). In addition to plane mirrors, it can also be made into a pyramidal array using K9 optical glass to enhance the laser's mechanical robustness.

[0014] Silicon is the substrate wafer material and serves as the basic material for semiconductor chips, carrying and connecting electronic components, a template for etching and photolithography, heat dissipation, and mechanical support.

[0015] The cavity wafer material is glass and silicon dioxide, which are the basic materials for semiconductor chip manufacturing. They provide a physical carrier for chip manufacturing and can be etched to form tiny circuit structures.

[0016] The cover plate wafer material is silicon, which is the basic material for semiconductor chips, carries and connects electronic components, serves as a template for etching and photolithography, and provides heat dissipation and mechanical support;

[0017] The first solder piece is used to connect the substrate wafer and the cavity wafer;

[0018] The second solder sheet is used to connect the cover plate wafer and the cavity wafer;

[0019] Getters are used to absorb gases and maintain a vacuum environment;

[0020] Ultimately, with weak feedback from the cavity mirror of the active optical clock resonator, Faraday active optical clock laser output was achieved.

[0021] Another objective of this invention is to provide a method for implementing a chip-based Faraday active optical clock, comprising the following steps:

[0022] 1) The fluorescence output by the semiconductor laser diode is linearly polarized light, which is collimated and transmitted through the substrate wafer to the first polarization beam splitter;

[0023] 2) The linearly polarized light is reflected by the first polarizing beam splitter, and the s-light is reflected into the MEMS alkali metal atom gas chamber;

[0024] 3) Due to the Faraday magneto-optical effect, the polarization direction of linearly polarized light passing through the MEMS alkali metal atom gas cell will rotate. By designing the length of the atom gas cell, the gas cell temperature, and the magnetic field strength of the permanent magnet, the polarization direction of the linearly polarized light can be rotated by 90°.

[0025] 4) Linearly polarized light rotated 90° can pass through a second polarizing beam splitter whose polarization direction is perpendicular to the first polarizing beam splitter.

[0026] 5) The linearly polarized light output from the second polarization beam splitter enters the active optical clock resonator mirror. Under the weak feedback of the active optical clock resonator mirror, laser oscillation is achieved. The Faraday active optical clock laser is reflected out from the second polarization beam splitter mirror and used as a narrow linewidth laser source or a high-performance optical frequency standard, which can be applied to the field of quantum precision measurement.

[0027] Advantages of this invention:

[0028] This invention proposes for the first time a chip-based Faraday active optical clock. ① The gain and frequency selection devices are separated, reducing interference from frequency selection on the gain, and the semiconductor gain is larger, making it easier to achieve laser oscillation. ② By adjusting the temperature to adjust the transmission spectrum bandwidth of the frequency selection device, the ratio of gain bandwidth to cavity mode bandwidth can be continuously adjusted, thereby continuously adjusting the bad cavity coefficient. ③ This invention proposes for the first time a scheme to compress the cavity length through MEMS integration, thereby improving the bad cavity coefficient. The smaller volume achieved through MEMS integration can improve the cavity attenuation rate, allowing the laser to operate in the bad cavity region, and greatly improving the practicality of the system. ④ By adjusting the bad cavity coefficient, the cavity attenuation rate can be adjusted to achieve the purpose of adjusting the laser linewidth.

[0029] By verifying the changes in laser linewidth under good cavity, bad cavity, and good-bad cavity proximity conditions, the significant contribution of the cavity pulling suppression effect introduced by the bad cavity to laser linewidth narrowing is demonstrated, enabling the realization of a continuous-wave active optical clock superradiative laser source with minimal linewidth. The laser linewidth is 100Hz, far smaller than the gain attenuation rate, and the transmission spectrum gain bandwidth is 1GHz, i.e., the gain attenuation rate is 10nm = 10000pm = 4000GHz, achieving a laser linewidth far smaller than the gain attenuation rate of 4×10⁻⁶. 10 A chip-driven active optical clock. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of one embodiment of a chip-based Faraday active optical clock according to the present invention.

[0031] Explanation of reference numerals in the attached figures: 1-Semiconductor laser diode, 2-First polarizing beam splitter, 3-MEMS alkali metal atom gas cell, 4-Second polarizing beam splitter, 5-First permanent magnet, 6-Second permanent magnet, 7-Active optical clock resonator mirror, 8-Substrate wafer, 9-Cavity wafer, 10-Cover wafer, 11-First solder sheet, 12-Second solder sheet, 13-Getting agent. Detailed Implementation

[0032] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0033] Example 1

[0034] like Figure 1 As shown, a chip-based Faraday active optical clock of this embodiment includes: a semiconductor laser diode 1, a first polarizing beam splitter 2, a MEMS alkali metal atom gas cell 3, a second polarizing beam splitter 4, a first permanent magnet 5, a second permanent magnet 6, an active optical clock resonant cavity mirror 7, a substrate wafer 8, a cavity wafer 9, a cover plate wafer 10, a first solder sheet 11, a second solder sheet 12, and a getter 13.

[0035] Among them, semiconductor laser diode 1 serves as the gain medium of the chip-based Faraday active optical clock, outputting a fluorescence signal. The center wavelength is related to the type of atomic transition in the atomic filter, including but not limited to 767nm, 770nm, 780nm, 795nm, 852nm, and 894nm, which correspond to the D2 and D1 transition lines of potassium, rubidium, and cesium atoms, respectively. The quantum well materials for different wavelengths are different, such as GaAs and InGaAs. Semiconductor laser diode 1 has an FP cavity structure with high reflectivity at the rear cavity surface and high transmittance at the front cavity surface to prevent the generation of internal cavity modes.

[0036] The polarization directions of the first polarizing beam splitter 2 and the second polarizing beam splitter 4 are perpendicular; the material chosen is K9 glass (optical borosilicate glass);

[0037] The MEMS alkali metal atom gas cell 3 can be filled with potassium atoms, rubidium atoms, and potassium atoms. Each light-transmitting hole is plated with metal and connected to 4 electrode pins to achieve the effect of heating the gas cell to increase the atomic number density and temperature control. In order to achieve better frequency selectivity bandwidth and transmittance, the gas cell generally needs to be heated to 100°C. The material selected is high borosilicate glass or silicon.

[0038] The first permanent magnet 5 and the second permanent magnet 6 are used to generate a uniform magnetic field along the direction of light propagation in the air chamber.

[0039] The first polarizing beam splitter 2, the second polarizing beam splitter 4, the MEMS alkali metal atom gas cell 3, the first permanent magnet 5, and the second permanent magnet 6 together form a Faraday atom filter, which achieves frequency selective filtering of broadband fluorescence signals. At the same time, the transmission bandwidth of this Faraday atom filter directly determines the gain attenuation rate Γ, which is generally 2π×1GHz. Only light with transition frequencies near the atomic resonance frequency can achieve polarization direction rotation and be output from the second polarizing beam splitter 4.

[0040] The active optical clock resonator mirror 7 is used to achieve optical feedback. The mirror does not need to have a very high reflectivity, thereby increasing the cavity attenuation rate κ. κ is jointly determined by the mirror reflectivity and the transmittance of the Faraday atom filter. By changing the reflectivity parameters of the Faraday atom filter and the mirror to make κ > Γ, the laser operates in the bad cavity region. The material chosen is ULE glass (zero expansion glass, titanium dioxide-silicate glass). In addition to plane mirrors, it can also be made into a pyramidal array, using K9 optical glass, thereby enhancing the laser's mechanical robustness.

[0041] The substrate wafer serves as the supporting structure for the entire chip, providing mechanical and thermal stability. The substrate wafer is typically made of materials with high thermal conductivity and low coefficient of thermal expansion, ensuring stable operation of the chip in different environments.

[0042] The cavity wafer 9, together with the substrate wafer 8 and the cover wafer 10, forms a closed cavity; the cavity wafer 9 can be filled with a specific gas or a vacuum environment to optimize optical performance.

[0043] The cover wafer 10 is used to enclose the cavity and protect the internal components from external contamination and mechanical damage; the cover wafer 10 typically has high transparency to ensure smooth transmission of optical signals;

[0044] The first solder piece 11 is used to connect the substrate wafer 8 and the cavity wafer 9; the melting point and material properties of the solder piece need to match the substrate and the cavity wafer to ensure the reliability and stability of the connection.

[0045] The second solder sheet 12 is used to connect the cover plate wafer 10 and the cavity wafer 9;

[0046] Getter 13 is used to absorb gas in the sealed chamber, maintain the vacuum environment of the sealed chamber, thereby improving the performance and lifespan of optical components and reducing gas interference with optical signals;

[0047] Finally, with the weak optical feedback of the active optical clock resonator mirror 7, the laser output of the Faraday active optical clock is realized.

[0048] This embodiment of a chip-based Faraday active optical clock implementation method includes the following steps:

[0049] 1) The fluorescence output by the semiconductor laser diode 1 is linearly polarized light, which is collimated and transmitted through the substrate wafer 8 to the first polarization beam splitter 2;

[0050] 2) The linearly polarized light is reflected by the first polarizing beam splitter 2, and the s-light is reflected into the MEMS alkali metal atom gas chamber 3;

[0051] 3) Due to the Faraday magneto-optical effect, the polarization direction of the linearly polarized light passing through the MEMS alkali metal atom gas cell 3 will rotate. By designing the length of the atom gas cell, the gas cell temperature, and the magnetic field strength of the permanent magnet, the polarization direction of the linearly polarized light can be rotated by 90°.

[0052] 4) Linearly polarized light rotated 90° can pass through the second polarizing beam splitter 4, whose polarization direction is perpendicular to the first polarizing beam splitter 2;

[0053] 5) The linearly polarized light output from the second polarization beam splitter 4 is incident on the active optical clock resonator 7. Under the weak feedback of the active optical clock resonator 7, laser oscillation is realized. The Faraday active optical clock laser is reflected out from the second polarization beam splitter 4 and used as a narrow linewidth laser source or a high-performance optical frequency standard, which can be applied to the field of quantum precision measurement.

[0054] Finally, it should be noted that the purpose of disclosing the embodiments is to help further understand the present invention. However, those skilled in the art will understand that various substitutions and modifications are possible without departing from the spirit and scope of the present invention and the appended claims. Therefore, the present invention should not be limited to the content disclosed in the embodiments, and the scope of protection of the present invention is defined by the claims.

Claims

1. A chip-scale Faraday active optical clock, characterized by, The semiconductor laser diode (1), the base wafer (8), the cover wafer (10), the base wafer (8) is provided with the cavity wafer (9), the cavity wafer (9) is provided with the first polarized light prism (2), the second polarized light prism (4), the MEMS alkali metal atom gas chamber (3), the active optical clock resonant cavity mirror (7), the cavity wafer (9) and the cover wafer (10) are connected to form a closed cavity;The polarization direction of the first polarized light prism (2) and the second polarized light prism (4) is perpendicular; The semiconductor laser diode (1) is used as a gain medium for outputting a wide spectrum fluorescent signal which is transmitted through the base wafer (8) and input into the first polarized light prism (2). The first polarized light prism (2) is used for dividing the wide spectrum fluorescent signal into two beams with different polarization directions, one of which enters the MEMS alkali metal atom gas chamber (3) for frequency locking. The MEMS alkali metal atom gas chamber (3) is used for selecting the frequency of the incident fluorescent signal to make the target wavelength laser transmit. The second polarized light prism (4) is used for dividing the target wavelength laser output by the MEMS alkali metal atom gas chamber (3) into two beams, one of which is used as a chipized Faraday active optical clock laser and is transmitted through the base wafer (8) for output, and the other of which is incident on the active optical clock resonant cavity mirror (7). The active optical clock resonant cavity mirror (7) is used for reflecting part of the incident laser back to the semiconductor laser diode (1) to realize continuous oscillation and frequency stability of the laser between the semiconductor laser diode (1) and the active optical clock resonant cavity mirror (7). Wherein, the reflectivity of the active optical clock resonant cavity mirror (7) and the transmittance of the MEMS alkali metal atom gas chamber (3) are adjusted to determine the cavity decay rate κ, and the transmission bandwidth of the MEMS alkali metal atom gas chamber (3) is adjusted to change the gain decay rate Γ, so that κ>Γ, so that the laser works in the bad cavity region.

2. The chip-scale Faraday active optical clock of claim 1, wherein, It also includes a first permanent magnet (5) and a second permanent magnet (6), the first permanent magnet (5) and the second permanent magnet (6) are used to generate a uniform magnetic field along the direction of light propagation in the MEMS alkali metal atom gas chamber (3), the first polarized light prism (2), the second polarized light prism (4), the MEMS alkali metal atom gas chamber (3), the first permanent magnet (5) and the second permanent magnet (6) constitute a Faraday atomic filter.

3. The on-chip Faraday active optical clock according to claim 1 or 2, wherein, Each light transmission hole surface of the MEMS alkali metal atom gas chamber (3) is plated with metal and connected with multiple electrode pins, which is used for heating the plated metal to increase the atomic number density of the MEMS alkali metal atom gas chamber (3) and control the temperature, and the material of the light transmission hole surface is high borosilicate glass or silicon.

4. The on-chip Faraday active optical clock according to claim 1, wherein, The transmission spectrum of the MEMS alkali metal atom gas chamber (3) is changed by adjusting the atomic number density filled in the MEMS alkali metal atom gas chamber (3), and the gain decay rate Γ is adjusted.

5. The on-chip Faraday active optical clock according to claim 1, wherein, It also includes a getter (13) for absorbing the gas in the closed cavity to maintain the vacuum environment of the closed cavity.

6. The on-chip Faraday active optical clock according to claim 1, wherein, The base wafer (8) is connected with the cavity wafer (9) through the first solder sheet (11); and the cover wafer (10) is connected with the cavity wafer through the second solder sheet (12).

7. The on-chip Faraday active optical clock according to claim 1, wherein, The materials of the first polarization beam splitter prism (2) and the second polarization beam splitter prism (4) are K9 glass.

8. The on-chip Faraday active optical clock according to claim 1, wherein, The atoms filled in the MEMS alkali metal atom cell (3) are potassium atoms, and the center wavelength of the wide-spectrum fluorescent signal corresponds to the D2 and D1 transition lines of the potassium atoms; the atoms filled in the MEMS alkali metal atom cell (3) are rubidium atoms, and the center wavelength of the wide-spectrum fluorescent signal corresponds to the D2 and D1 transition lines of the rubidium atoms; or the atoms filled in the MEMS alkali metal atom cell (3) are cesium atoms, and the center wavelength of the wide-spectrum fluorescent signal corresponds to the D2 and D1 transition lines of the cesium atoms.

9. A method for implementing a chip-based Faraday active optical clock, comprising the following steps: 1) arranging a cavity wafer (9) on a base wafer (8), arranging a first polarization beam splitter prism (2), a second polarization beam splitter prism (4), a MEMS alkali metal atom cell (3), and an active optical clock resonant cavity mirror (7) in the cavity wafer (9), and connecting the cavity wafer (9) with a cover wafer (10) to form a sealed cavity; the polarization directions of the first polarization beam splitter prism (2) and the second polarization beam splitter prism (4) are perpendicular to each other; 2) using a semiconductor laser diode (1) to output a linearly polarized wide-spectrum fluorescent signal, which is collimated and transmitted through the base wafer (8) to the first polarization beam splitter prism (2); 3) the first polarization beam splitter prism (2) divides the incident light beam into two beams with different polarization directions, and reflects one of the two beams into the MEMS alkali metal atom cell (3); 4) the MEMS alkali metal atom cell (3) generates a Faraday magneto-optical effect on the incident light, so that the polarization direction of the incident light is rotated by 90° and then the light is incident on the second polarization beam splitter prism (4); 5) the second polarization beam splitter prism (4) divides the laser output by the MEMS alkali metal atom cell (3) into two beams, one of which is transmitted through the base wafer (8) as the laser of the chip-based Faraday active optical clock, and the other of which is incident on the active optical clock resonant cavity mirror (7); 6) the active optical clock resonant cavity mirror (7) reflects part of the incident laser back to the semiconductor laser diode (1), so as to realize continuous oscillation and frequency stability of the laser between the semiconductor laser diode (1) and the active optical clock resonant cavity mirror (7); wherein the cavity decay rate κ is determined by adjusting the reflectivity of the active optical clock resonant cavity mirror (7) and the transmittance of the MEMS alkali metal atom cell (3), and the gain decay rate Γ is changed by adjusting the transmission bandwidth of the MEMS alkali metal atom cell (3), so that κ>Γ, so that the laser works in the bad cavity region.

10. The method of claim 9, wherein, Two ends of the MEMS alkali metal atom gas chamber (3) are provided with a first permanent magnet (5) and a second permanent magnet (6) for generating a uniform magnetic field along the light propagation direction in the MEMS alkali metal atom gas chamber (3); the first polarization light splitting prism (2), the second polarization light splitting prism (4), the MEMS alkali metal atom gas chamber (3), the first permanent magnet (5) and the second permanent magnet (6) constitute a Faraday atomic optical filter.

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