Optical device for improving the interference properties of an atomic beam
By using an optical device with a cooling unit and a 45° V-shaped mirror to adjust the polarization of Raman light in an atomic beam interferometry system, the problems of complex optical path and wavefront error were solved, the contrast and measurement accuracy of atomic beam interferometry signals were improved, and efficient optical power utilization and long-term stability were achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHINA STATE SHIPBUILDING CORP NO 707 RES INST
- Filing Date
- 2026-03-31
- Publication Date
- 2026-06-12
AI Technical Summary
In the existing technology, atomic beam interferometry systems have problems such as complex Raman light reflection paths, low optical power utilization, large wavefront errors, and difficulty in adjusting the parallelism of multiple Raman beams, resulting in insufficient contrast of interference signals and measurement accuracy.
An optical device including an atomic furnace, vacuum cavity, cooling unit, state selection unit, interference unit, and fluorescence detection unit is used. A standing wave field is formed by cooling optical tubes and mirrors in the y and x directions to slow down the diffusion. Combined with a 45° V-shaped mirror and a λ/4 waveplate to adjust the polarization of the Raman light, collimated Raman light with a flat-top distribution is output to ensure that the three Raman beams are parallel and reduce wavefront error.
Simplify the optical path, improve optical power utilization, reduce wavefront error, enhance the contrast and signal-to-noise ratio of atomic beam interference fringes, and improve measurement accuracy and long-term stability.
Smart Images
Figure CN122192387A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of atomic interference technology, and in particular to an optical device for improving the interference characteristics of atomic beams. Background Technology
[0002] Quantum precision measurement technology can surpass the precision limit of classical physics and has great application potential in fields such as inertial navigation and time and frequency reference. Using atomic beams as interference sources can eliminate the measurement dead zone in time of atomic clusters, taking into account the measurement advantages of high precision and large bandwidth. In atomic beam interference systems, in order to increase the Raman transition linewidth and thus be able to interfere with atoms with a wider velocity distribution, it is usually necessary to make the Raman spot width very narrow along the atomic flight direction. The commonly used methods are: (1) using a cylindrical lens to focus the collimated Raman light in one direction, thereby forming a thin and long spot at the focal plane of the cylindrical lens. However, the spot size of the focused Raman light produced by this method is inconsistent at different optical paths, resulting in a more complex Raman light reflection path and difficulty in adjustment; (2) using an aperture to directly block the collimated Raman light to form a thin strip spot. However, large-area blocking will cause a large waste of laser power, and diffraction will occur at the edge of the aperture when the light transmission size is small, affecting the Raman beam quality. Moreover, the Raman light generated by the above methods is a Gaussian beam, which introduces wavefront error when interacting with atoms, causing atoms at different spatial positions to acquire inconsistent phase accumulation, thereby degrading the contrast of the atomic beam interference signal and the measurement accuracy.
[0003] Furthermore, achieving atomic interference requires three Raman beams (π / 2-π-π / 2) to split, reverse, and recombine the atomic beam, thus forming an interference loop. When the Raman beam illuminates the atomic beam, the atoms experience a back impulse in the same direction as the effective wave vector of the Raman beam. If the parallelism of the effective wave vectors among the multiple Raman beams is deviated, due to the conservation of momentum, the two interference paths cannot close after the last Raman beam, thus preventing interference. Therefore, ensuring the parallelism between the multiple Raman beams is crucial for improving the contrast and signal-to-noise ratio of the atomic beam interference fringes. Summary of the Invention
[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide an optical device that can greatly improve the contrast and signal-to-noise ratio of atomic beam interference fringes, and ultimately improve the measurement accuracy and long-term stability of the atomic beam interference system, thereby enhancing the characteristics of atomic beam interference.
[0005] The above-mentioned objective of this invention is achieved through the following technical solution: An optical device for improving the interference characteristics of atomic beams, characterized in that it includes an atomic furnace, a vacuum cavity, a multi-segment cooling unit in the y-direction, a multi-segment cooling unit in the x-direction, a state selection unit, an interference interaction unit, and a fluorescence detection unit; The vacuum cavity is divided into a cooling zone, a state selection zone, an interference zone, and a detection zone from one end to the other. The atomic furnace is located at one end of the vacuum chamber and connected to the cooling zone to generate atomic beams; The y-axis multi-segment cooling unit includes a y-axis multi-segment cooling light tube and a y-axis cooling light reflector. The y-axis multi-segment cooling light tube and the y-axis cooling light reflector are arranged opposite each other in the horizontal direction on both sides of the cooling area outside the vacuum cavity. The two work together to generate a horizontal cooling light standing wave field to slow down the diffusion of the atomic beam in the horizontal direction. The x-axis multi-segment cooling unit includes an x-axis multi-segment cooling light tube and an x-axis cooling light reflector. The x-axis multi-segment cooling light tube and the x-axis cooling light reflector are arranged opposite each other on both sides of the cooling area outside the vacuum cavity in the vertical direction. The two work together to generate a vertical cooling light standing wave field to slow down the diffusion of the atomic beam in the vertical direction. The state selection unit includes a state selection optical tube and a state selection optical reflector. The state selection optical tube and the state selection optical reflector are arranged opposite each other in the horizontal direction on both sides of the state selection area outside the vacuum cavity. The two work together to generate a state selection optical standing wave field. Under the optical pumping action of the standing wave field, the atoms are made to be in a magnetically insensitive state. The interference unit includes a Raman beam shaping tube, a first V-shaped mirror, a second V-shaped mirror, a third V-shaped mirror, a first λ / 4 waveplate, a second λ / 4 waveplate, a third λ / 4 waveplate, a first Raman beam reflecting mirror, a second Raman beam reflecting mirror, and a third Raman beam reflecting mirror; the apex angles of the first V-shaped mirror, the second V-shaped mirror, and the third V-shaped mirror are all 45°. The Raman beam shaping tube is used to output collimated, elongated Raman beams with a flat-top distribution; the first V-shaped mirror, the second V-shaped mirror, and the third V-shaped mirror are sequentially disposed on one side of the interference region outside the vacuum cavity; the first λ / 4 waveplate, the second λ / 4 waveplate, and the third λ / 4 waveplate are sequentially disposed on the other side of the interference region outside the vacuum cavity, and are respectively arranged opposite to the first V-shaped mirror, the second V-shaped mirror, and the third V-shaped mirror in the horizontal direction; the first Raman beam reflecting mirror, the second Raman beam reflecting mirror, and the third Raman beam reflecting mirror are respectively arranged opposite to each other on the outside of the first λ / 4 waveplate, the second λ / 4 waveplate, and the third λ / 4 waveplate; The first V-shaped mirror, the first λ / 4 waveplate, and the first Raman reflector work together to generate π / 2 Raman light with mutually perpendicular polarization directions; the second V-shaped mirror, the second λ / 4 waveplate, and the second Raman reflector work together to generate π Raman light with mutually perpendicular polarization directions; the third V-shaped mirror, the third λ / 4 waveplate, and the third Raman reflector work together to generate π / 2 Raman light with mutually perpendicular polarization directions; the atomic beams interfere with each other under the action of the three parallel Raman beams with a flat-top distribution. The fluorescence detection unit includes a detection light tube, a detection light reflector, and a fluorescence collection device. The detection light tube and the detection light reflector are arranged horizontally opposite each other on both sides of the detection area outside the vacuum cavity, and the fluorescence collection device is located above the detection area outside the vacuum cavity. The detection light and the detection light reflector work together to generate a detection light standing wave field. The standing wave field interacts with the interfering atomic beam to emit fluorescence, and the fluorescence collection device is used to collect the emitted fluorescence.
[0006] Furthermore, the front reflective surface of the first V-shaped mirror is coated with a 780nm wavelength T=75% partial transmission film, and the rear reflective surface is coated with a 780nm wavelength high reflective film; the front reflective surface of the second V-shaped mirror is coated with a 780nm wavelength T=33% partial transmission film, and the rear reflective surface is coated with a 780nm wavelength high reflective film; the front and rear reflective surfaces of the third V-shaped mirror are both coated with a 780nm wavelength high reflective film.
[0007] Furthermore, the internal structure of the Raman beam shaping tube includes an optical fiber adapter flange, a short-focal-length lens, a Powell prism, and a cemented doublet achromatic cylindrical lens. Raman light enters the Raman beam shaping tube via a polarization-maintaining fiber fixed to the optical fiber adapter flange, which is located at the focal length of the short-focal-length lens. The Raman light is collimated under the action of the short-focal-length lens. The collimated Raman light is incident on the apex of the Powell prism, where the beam size remains constant in the direction parallel to the apex and diverges in the direction perpendicular to the apex. The apex of the cemented doublet achromatic cylindrical lens is placed parallel to the apex edge of the Powell prism. After passing through the cemented doublet achromatic cylindrical lens, the Raman light maintains a constant beam size in the direction parallel to the apex and diverges in the direction perpendicular to the apex, resulting in a collimated beam with a flat-topped intensity distribution. The cemented doublet achromatic cylindrical lens is composed of two cemented parts of different glass grades.
[0008] Furthermore, the internal structures of both the y-axis and x-axis multi-segment cooling optical tubes include a laser collimator, a first beam splitter, a second beam splitter, and a right-angle prism. The cooling light passes through the laser collimator to form a collimated spot. The first beam splitter has a transmittance-to-reflection ratio of 60 / 30 for a wavelength of 780nm. After passing through the first beam splitter, part of the cooling light is reflected into the vacuum cavity, and the remaining part is transmitted into the second beam splitter. The second beam splitter has a transmittance-to-reflection ratio of 45 / 45 for a wavelength of 780nm. After passing through the second beam splitter, part of the cooling light is reflected into the vacuum cavity, and the remaining part is transmitted into the right-angle prism and reflected into the vacuum cavity.
[0009] Moreover, both the y-direction cooling optical reflector and the x-direction cooling optical reflector function as 780nm quarter-wave plates, and are coated with a 780nm wavelength high-reflectivity film on the lower surface of the reflector.
[0010] Furthermore, the selected light reflector and the probe light reflector are coated with a 780nm wavelength high-reflectivity film.
[0011] Furthermore, the selected state region and the interference region are equipped with a bias magnetic field, the direction of which is set horizontally.
[0012] The advantages and beneficial effects of this invention are as follows: 1. An optical device for improving the interference characteristics of atomic beams according to the present invention uses a collimated, slender, flat-top beam to control the interference of atomic beams, which ensures a simple and compact optical path, improves the utilization rate of optical power, and avoids the atomic interference measurement error caused by the inherent wavefront error of Gaussian beams. 2. The present invention provides an optical device for improving the interference characteristics of atomic beams. It innovatively uses three V-shaped mirrors with a vertex angle of 45° to transmit Raman light. Based on the characteristic that the outgoing light is always perpendicular to the incident light, it fundamentally ensures that the three Raman beams are parallel to each other, reducing the difficulty of adjusting the parallelism of multi-beam Raman light.
[0013] 3. The optical device of the present invention for improving the characteristics of atomic beam interference can greatly improve the contrast and signal-to-noise ratio of atomic beam interference fringes by reducing the wavefront error of Raman light and improving the parallelism of Raman light, and ultimately improve the measurement accuracy and long-term stability of the atomic beam interference system. Attached Figure Description
[0014] Figure 1 This is a schematic diagram (top view) of an optical device for improving the interference characteristics of atomic beams. Figure 2 This is a schematic diagram of the internal structure of a Raman beam shaping tube in an optical device for enhancing the interference characteristics of atomic beams; Figure 3 This is a schematic diagram of light transmission within a V-shaped mirror in an optical device for enhancing the interference characteristics of atomic beams. In the diagram: 1. Atomic furnace; 2. Vacuum cavity; 3-1. Y-axis multi-segment cooling light tube; 3-2. X-axis multi-segment cooling light tube; 4-1. Y-axis cooling light reflector; 4-2. X-axis cooling light reflector; 5. Selective light tube; 6. Selective light reflector; 7. Raman light shaping light tube; 701. Fiber optic adapter flange; 702. Short focal length lens; 703. Powell prism; 704. Cemented doublet achromatic cylindrical lens; 8-1. First V-shaped mirror; 8-2. Second V-shaped mirror; 8-3. Third V-shaped mirror; 9-1. First λ / 4 waveplate; 9-2. Second λ / 4 waveplate; 9-3. Third λ / 4 waveplate; 10-1. First Raman light reflector; 10-2. Second Raman light reflector; 10-3. Third Raman light reflector; 11. Detector light tube; 12. Detector light reflector; 13. Fluorescence collection device. Detailed Implementation
[0015] The present invention will be further described in detail below through specific embodiments. The following embodiments are merely descriptive and not limiting, and should not be used to limit the scope of protection of the present invention.
[0016] An optical device for improving the interference characteristics of atomic beams, such as Figures 1-3 As shown, it includes an atomic furnace 1, a vacuum chamber 2, a multi-segment cooling light tube 3-1 in the y-direction, a multi-segment cooling light tube 3-2 in the x-direction, a cooling light reflector 4-1 in the y-direction, a cooling light reflector 4-2 in the x-direction, a selective light tube 5, a selective light reflector 6, a Raman light shaping light tube 7, a first V-shaped mirror 8-1, a second V-shaped mirror 8-2, a third V-shaped mirror 8-3, a first λ / 4 waveplate 9-1, a second λ / 4 waveplate 9-2, a third λ / 4 waveplate 9-3, a first Raman light reflector 10-1, a second Raman light reflector 10-2, a third Raman light reflector 10-3, a detection light tube 11, a detection light reflector 12, and a fluorescence collection device 13.
[0017] Among them, the y-direction multi-segment cooling light tube 3-1 and the y-direction cooling light reflector 4-1 constitute the y-direction multi-segment cooling unit; the x-direction multi-segment cooling light tube 3-2 and the x-direction cooling light reflector 4-2 constitute the x-direction multi-segment cooling unit; the state selection light tube 5 and the state selection light reflector 6 constitute the state selection unit; the Raman light shaping light tube 7, the first V-shaped mirror 8-1, the second V-shaped mirror 8-2, the third V-shaped mirror 8-3, the first λ / 4 waveplate 9-1, the second λ / 4 waveplate 9-2, the third λ / 4 waveplate 9-3, the first Raman light reflector 10-1, the second Raman light reflector 10-2, and the third Raman light reflector 10-3 constitute the interference unit; the detection light tube 11, the detection light reflector 12, and the fluorescence collection device 13 constitute the fluorescence detection unit.
[0018] Rubidium in Furnace 1 87 Rb atoms move into vacuum cavity 2 under heating, and are subjected to transverse laser cooling effects from a horizontal (y-direction) cooling light standing wave field formed by the y-direction multi-segment cooling light cylinder 3-1 and the y-direction cooling light reflector 4-1, and a vertical (x-direction) cooling light standing wave field formed by the x-direction multi-segment cooling light cylinder 3-2 and the x-direction cooling light reflector 4-2. The frequency of the cooling light is related to... 87 Rb atom D2 line 5 2 S 1 / 2 F=2→5 2 P 3 / 2The F'=3 resonant transition exhibits red detuning at a wavelength of 780nm. Both the y-axis cooling light reflector 4-1 and the x-axis cooling light reflector 4-2 function as 780nm quarter-wave plates, and are coated with a 780nm high-reflectivity film on their lower surfaces, ensuring that the polarization direction of the reflected light is orthogonal to that of the incident light. The internal structures of both the y-axis multi-segment cooling light tube 3-1 and the x-axis multi-segment cooling light tube 3-2 include a laser collimator, a first beam splitter, a second beam splitter, and a right-angle prism. The cooling light passes through the laser collimator to form a collimated spot. The first beam splitter has a 60 / 30 transmittance / reflection ratio for the 780nm wavelength. After passing through the first beam splitter, part of the cooling light is reflected into the vacuum cavity 2, and the remaining portion is transmitted into the second beam splitter. The second beam splitter has a transmittance-to-reflectance ratio of 45 / 45 for a wavelength of 780nm. After passing through the second beam splitter, part of the cooled light is reflected into vacuum cavity 2, and the remaining part is transmitted into the right-angle prism, where it is reflected back into vacuum cavity 2. The spacing between the beam splitters and the right-angle prism is kept as small as possible, which extends the cooling length while maintaining a compact optical path.
[0019] The laterally cooled atomic beam enters the selected state region. The selected light contains two frequencies of laser light, which are respectively... 87 Rb atom D2 line 5 2 S 1 / 2 F=1→5 2 P 3 / 2 F'=0 transition and 5 2 S 1 / 2 F=2→5 2 P 3 / 2 F'=2 transition resonance. Under the optical pumping effect of the standing wave field formed by the selected optical tube 5 and the selected optical reflector 6, the atom is in a magnetically insensitive state |F=1,m F =0>Up, entering the interference region. The selected-state reflector 6 is coated with a 780nm wavelength high-reflectivity film. There are bias magnetic fields in the selected-state region and the interference region, and the magnetic field direction is set along the y-direction.
[0020] The Raman beam shaping tube 7 outputs collimated, slender Raman beams with a flat-top distribution, which are incident on the first V-shaped mirror 8-1. The Raman beams are coupled with the ground state 5. 2 S 1 / 2 F=1 and 5 2 S 1 / 2 The transition between two energy levels with F=2, the frequency difference between the two beams of light is 6.834 GHz, and the distance from the excited state is 5. 2 P 3 / 2The F'=1 transition involves a significant frequency detuning to avoid the influence of spontaneous emission during stimulated Raman transitions. The apex angle of the first V-shaped mirror 8-1 is 45°. The front reflective surface is coated with a 780nm wavelength T=75% partial transmission film, and the rear reflective surface is coated with a 780nm wavelength high-reflection film. The Raman light reflected by the two reflective surfaces of the first V-shaped mirror 8-1 exits in an orthogonal direction with the Raman light incident on the first V-shaped mirror 8-1, and enters the vacuum cavity 2 as π / 2 Raman light. Meanwhile, the Raman light transmitted through the front reflective surface of the first V-shaped mirror 8-1 is incident on the second V-shaped mirror 8-2. The second V-shaped mirror 8-2 has a 45° apex angle. Its front reflective surface is coated with a 780nm wavelength T=33% partial transmission film, and its rear reflective surface is coated with a 780nm wavelength high-reflectivity film. The Raman light reflected from both reflective surfaces of the second V-shaped mirror 8-2 exits in an orthogonal direction with the Raman light incident on the second V-shaped mirror 8-2, entering the vacuum cavity 2 as π Raman light. The Raman light transmitted through the front reflective surface of the second V-shaped mirror 8-2 enters the third V-shaped mirror 8-3. The third V-shaped mirror 8-3 also has a 45° apex angle, and both its front and rear reflective surfaces are coated with a 780nm wavelength high-reflectivity film. The Raman light reflected from both reflective surfaces of the third V-shaped mirror 8-3 exits in an orthogonal direction with the Raman light incident on the third V-shaped mirror 8-3, entering the vacuum cavity 2 as π / 2 Raman light. Since the Raman light incident on the first V-shaped mirror 8-1, the second V-shaped mirror 8-2, and the third V-shaped mirror 8-3 is in the same direction, the Raman light exiting the three V-shaped mirrors is parallel to each other. Passing through the vacuum cavity 2, its polarization direction is adjusted by the first λ / 4 waveplate 9-1, the second λ / 4 waveplate 9-2, and the third λ / 4 waveplate 9-3, respectively. It is then reflected by the first Raman light reflecting mirror 10-1, the second Raman light reflecting mirror 10-2, and the third Raman light reflecting mirror 10-3 and re-enters the vacuum cavity 2. The polarization directions of the incident and reflected Raman light are orthogonal to each other. The atomic beam interferes under the action of the three parallel Raman beams with a flat-top distribution. The standing wave field formed by the probe light 11 and the probe light reflecting mirror 12 interacts with the interfered atomic beam to emit fluorescence, which is collected by the fluorescence collection device 13 installed in the vertical direction of the probe light transmission. The frequency of the probe light and... 87 Rb atom D2 line 5 2 S 1 / 2 F=2→5 2 P 3 / 2 F'=3 transition resonance, probe light reflector 12 is coated with a 780nm wavelength high reflectivity film.
[0021] The internal structure of the Raman light shaping tube 7 is as follows: Figure 2As shown, the system includes a fiber optic adapter flange 701, a short-focal-length lens 702, a Powell prism 703, and a cemented doublet achromatic cylindrical lens 704. Raman light enters the Raman light shaping tube 7 via a polarization-maintaining fiber fixed to the fiber optic adapter flange 701, which is located at the focal length of the short-focal-length lens 702. The short-focal-length lens 702 has a focal length of 6 mm. Raman light transmitted with a numerical aperture of NA = 0.12 is collimated by the short-focal-length lens 702, resulting in a spot diameter of 1 mm. The collimated Raman light is incident on the apex of the Powell prism 703. The beam size remains unchanged in the direction parallel to the apex (y-direction), while the beam diverges in the direction perpendicular to the apex (x-direction) with a fan angle of 30°. The cemented doublet achromatic cylindrical lens 704 has a focal length of 30mm. Its cylindrical apex is placed parallel to the apex edge of the Powell prism 703. After Raman light passes through the cemented doublet achromatic cylindrical lens 704, the beam size remains unchanged in the direction parallel to the cylindrical apex (y-direction), while the diverging beam in the direction perpendicular to the cylindrical apex (x-direction) is collimated, resulting in a collimated beam with a flat-top intensity distribution. The beam length is 15.5mm and the width is 1mm. The cemented doublet achromatic cylindrical lens 704 is composed of two parts cemented together with different glass grades, which allows for smaller aberrations and a more uniform beam distribution in the collimated beam.
[0022] Figure 3 This is a schematic diagram of light transmission within a V-shaped mirror. Light is incident along the OA direction, reflected along the AB direction, and finally exits along the BO direction. QA and QB are the normals at incident points A and B, respectively, and they intersect at point Q. Since ∠APB = 45°, then ∠BAP + ∠ABP = 135°; since ∠QAP = ∠QBP = 90°, then ∠QAB + ∠QBA = (90° - ∠BAP) + (90° - ∠ABP) = 45°; and since ∠OAQ = ∠QAB and ∠OBQ = ∠QBA, then ∠OAB + ∠OBA = 2(∠QAB + ∠QBA) = 90°, therefore OA⊥OB. Therefore, for a V-shaped mirror with a 45° apex angle, regardless of the change in the incident angle within the V-shaped mirror, the outgoing light after two reflections is always perpendicular to the incident light. Thus, when the incident light direction is constant, regardless of the placement of the apex angles of the first V-shaped mirror 8-1, the second V-shaped mirror 8-2, and the third V-shaped mirror 8-3, the outgoing light is always parallel to each other, greatly reducing the adjustment error of the multi-beam parallelism. To change the outgoing light direction, only the incident light direction needs to be changed accordingly. This can be achieved by adjusting the Raman light transmission direction of the Raman light shaping tube 7, thereby changing the angle between the Raman light entering the vacuum cavity 2 and the atomic beam.
[0023] In this invention, the atomic furnace may also contain cesium (Cs) atoms or ytterbium (Yb) atoms, and the wavelengths of the cooling light, selected state light, Raman light and probe light will change accordingly. This invention does not limit the specific wavelengths of the atomic furnace.
[0024] In this invention, atomic furnaces can be set at both ends of the vacuum cavity, and cooling zones, state selection zones, and detection zones for opposing atomic beams can be added to achieve interference of atomic beams moving towards each other at both ends. This embodiment of the invention does not limit this.
[0025] Although the embodiments and drawings of the present invention have been disclosed for illustrative purposes, those skilled in the art will understand that various substitutions, variations and modifications are possible without departing from the spirit and scope of the invention and the appended claims. Therefore, the scope of the invention is not limited to the contents disclosed in the embodiments and drawings.
Claims
1. An optical device for improving the interference characteristics of atomic beams, characterized in that: It includes a nuclear furnace, a vacuum chamber, a y-axis multi-segment cooling unit, an x-axis multi-segment cooling unit, a state selection unit, an interference unit, and a fluorescence detection unit; The vacuum cavity is divided into a cooling zone, a state selection zone, an interference zone, and a detection zone from one end to the other. The atomic furnace is located at one end of the vacuum chamber and connected to the cooling zone to generate atomic beams; The y-axis multi-segment cooling unit includes a y-axis multi-segment cooling light tube and a y-axis cooling light reflector. The y-axis multi-segment cooling light tube and the y-axis cooling light reflector are arranged opposite each other in the horizontal direction on both sides of the cooling area outside the vacuum cavity. The two work together to generate a horizontal cooling light standing wave field to slow down the diffusion of the atomic beam in the horizontal direction. The x-axis multi-segment cooling unit includes an x-axis multi-segment cooling light tube and an x-axis cooling light reflector. The x-axis multi-segment cooling light tube and the x-axis cooling light reflector are arranged opposite each other on both sides of the cooling area outside the vacuum cavity in the vertical direction. The two work together to generate a vertical cooling light standing wave field to slow down the diffusion of the atomic beam in the vertical direction. The state selection unit includes a state selection optical tube and a state selection optical reflector. The state selection optical tube and the state selection optical reflector are arranged opposite each other in the horizontal direction on both sides of the state selection area outside the vacuum cavity. The two work together to generate a state selection optical standing wave field. Under the optical pumping action of the standing wave field, the atoms are made to be in a magnetically insensitive state. The interference unit includes a Raman beam shaping tube, a first V-shaped mirror, a second V-shaped mirror, a third V-shaped mirror, a first λ / 4 waveplate, a second λ / 4 waveplate, a third λ / 4 waveplate, a first Raman beam reflecting mirror, a second Raman beam reflecting mirror, and a third Raman beam reflecting mirror; the apex angles of the first V-shaped mirror, the second V-shaped mirror, and the third V-shaped mirror are all 45°. The Raman beam shaping tube is used to output collimated, elongated Raman beams with a flat-top distribution; the first V-shaped mirror, the second V-shaped mirror, and the third V-shaped mirror are sequentially disposed on one side of the interference region outside the vacuum cavity; the first λ / 4 waveplate, the second λ / 4 waveplate, and the third λ / 4 waveplate are sequentially disposed on the other side of the interference region outside the vacuum cavity, and are respectively arranged opposite to the first V-shaped mirror, the second V-shaped mirror, and the third V-shaped mirror in the horizontal direction; the first Raman beam reflecting mirror, the second Raman beam reflecting mirror, and the third Raman beam reflecting mirror are respectively arranged opposite to each other on the outside of the first λ / 4 waveplate, the second λ / 4 waveplate, and the third λ / 4 waveplate; The first V-shaped mirror, the first λ / 4 waveplate, and the first Raman reflector work together to generate π / 2 Raman light with mutually perpendicular polarization directions; the second V-shaped mirror, the second λ / 4 waveplate, and the second Raman reflector work together to generate π Raman light with mutually perpendicular polarization directions; the third V-shaped mirror, the third λ / 4 waveplate, and the third Raman reflector work together to generate π / 2 Raman light with mutually perpendicular polarization directions; the atomic beams interfere with each other under the action of the three parallel Raman beams with a flat-top distribution. The fluorescence detection unit includes a detection light tube, a detection light reflector, and a fluorescence collection device. The detection light tube and the detection light reflector are arranged horizontally opposite each other on both sides of the detection area outside the vacuum cavity, and the fluorescence collection device is located above the detection area outside the vacuum cavity. The detection light and the detection light reflector work together to generate a detection light standing wave field. The standing wave field interacts with the interfering atomic beam to emit fluorescence, and the fluorescence collection device is used to collect the emitted fluorescence.
2. The optical device for improving the interference characteristics of atomic beams according to claim 1, characterized in that: The first V-shaped mirror has a front reflective surface coated with a 780nm wavelength T=75% partial transmission film and a rear reflective surface coated with a 780nm wavelength high reflective film; the second V-shaped mirror has a front reflective surface coated with a 780nm wavelength T=33% partial transmission film and a rear reflective surface coated with a 780nm wavelength high reflective film; the third V-shaped mirror has both front and rear reflective surfaces coated with a 780nm wavelength high reflective film.
3. The optical device for improving the interference characteristics of atomic beams according to claim 1, characterized in that: The internal structure of the Raman optical shaping tube includes an optical fiber adapter flange, a short focal length lens, a Powell prism, and a cemented doublet achromatic cylindrical lens. Raman light enters the Raman light shaping tube via a polarization-maintaining fiber fixed on an optical fiber adapter flange, which is located at the focal length of a short-focal-length lens. The Raman light is collimated by the short-focal-length lens. The collimated Raman light is incident on the apex of a Powell prism. The beam size remains constant in the direction parallel to the apex edge, and diverges in the direction perpendicular to the apex edge. The apex of the cemented doublet achromatic cylindrical lens is placed parallel to the apex edge of the Powell prism. After passing through the cemented doublet achromatic cylindrical lens, the Raman light maintains a constant beam size in the direction parallel to the apex, and the diverging beam in the direction perpendicular to the apex is collimated, resulting in a collimated linear light spot with a flat-top intensity distribution. The cemented doublet achromatic cylindrical lens is composed of two parts cemented together from different glass grades.
4. The optical device for improving the interference characteristics of atomic beams according to claim 1, characterized in that: The internal structures of both the y-axis and x-axis multi-segment cooling optical tubes include a laser collimator, a first beam splitter, a second beam splitter, and a right-angle prism. Cooling light passes through the laser collimator to form a collimated spot. The first beam splitter has a transmittance-to-reflectance ratio of 60 / 30 for a wavelength of 780nm. After passing through the first beam splitter, part of the cooling light is reflected into the vacuum cavity, and the remaining portion is transmitted into the second beam splitter. The second beam splitter has a transmittance-to-reflectance ratio of 45 / 45 for a wavelength of 780nm. After passing through the second beam splitter, part of the cooling light is reflected into the vacuum cavity, and the remaining portion is transmitted into the right-angle prism, where it is reflected back into the vacuum cavity.
5. The optical device for improving the interference characteristics of atomic beams according to claim 1, characterized in that: Both the y-direction cooling optical reflector and the x-direction cooling optical reflector function as 780nm quarter-wave plates, and a 780nm wavelength high-reflectivity film is deposited on the lower surface of the reflector.
6. The optical device for improving the interference characteristics of atomic beams according to claim 1, characterized in that: The selected light reflector and the probe light reflector are coated with a 780nm wavelength high-reflectivity film.
7. The optical device for improving the interference characteristics of atomic beams according to claim 1, characterized in that: The selected state region and the interference region are equipped with a bias magnetic field, and the magnetic field direction is set in the horizontal direction.