Double-atomic-group synchronous cooling and trapping system

Abstract

The invention discloses a double-atomic-group synchronous cooling and trapping system which comprises a laser beam, a first magnetic field coil pair, a first cone mirror, a second magnetic field coil pair, a second cone mirror, a quarter-wave plate and a plane mirror. The first cone mirror reflects half-power laser beams and transmits the other half-power laser beams, the second cone mirror reflects all-power laser beams, the laser beams are spread from top to bottom and form cooling light pairs after passing through the first cone mirror and the second cone mirror, and synchronous cooling and trapping of double atomic groups can be achieved by combining the pairing effect of the magnetic field coils. The system is simple in structure and convenient to realize, and can effectively improve the trapping consistency of the two atomic groups.

Description

Technical Field

[0001] The invention belongs to the technical field of atomic cooling and trapping of atoms in an atomic interferometer, and in particular relates to a diatomic cluster synchronous cooling and trapping system. Background Art

[0002] The atomic gravity gradiometer can be used to accurately measure information such as gravity gradient, and has important application value in resource exploration, autonomous navigation, gravity field mapping and other fields. The atomic gravity gradiometer mainly uses lasers to simultaneously trap and manipulate two atomic clusters, and then detects the population information of the atomic clusters to extract gravity gradient information. During the measurement process, the two atomic clusters have most of the same noise sources, and the common mode noise can be effectively suppressed through differential calculation. Therefore, the atomic gravity gradiometer has extremely high measurement sensitivity and accuracy.

[0003] At present, the main methods for cooling and trapping atoms are "six-beam laser beam", "three-beam laser reflection" and "single-beam cone reflection". In the atomic gravity gradient instrument, the first two methods require twelve and six laser beams respectively to trap two groups of atoms, while the third method only requires one laser beam to trap two groups of atoms at the same time, which significantly reduces the complexity of the system and the difficulty of installation and adjustment, and has been widely used.

[0004] Moquis Company disclosed a cold atom gravity gradiometer (patent publication number CN105026960A), which realizes synchronous cooling and trapping of two atomic clusters through a large conic mirror and a small conic mirror. However, due to the different laser powers and beam sizes acting on the two atomic clusters, the consistency of the two atomic clusters is poor, which seriously affects the interferometric measurement results of the atomic gravity gradiometer; Huazhong University of Science and Technology disclosed an atomic gravity gradiometer based on staggered conic mirrors (patent publication number CN114236629A), which realizes synchronous cooling and trapping of the two atomic clusters by staggered placement of two special conical mirrors, so that the laser power and beam size acting on the two atomic clusters are the same, and improves the consistency of the atomic cluster trapping. However, the conical mirror proposed in the patent has a special structure, is difficult to process, and has high requirements for assembly precision. Summary of the invention

[0005] Based on the above-mentioned deficiencies in the prior art, the present invention provides a diatomic cluster synchronous cooling and trapping system based on a semi-transparent and semi-reflective corner cone to solve the technical problems of complex structure of the diatomic cluster cooling and trapping system and poor consistency of the diatomic clusters in the prior art.

[0006] The technical solution adopted by the present invention to solve its technical problem is: a diatomic cluster synchronous cooling and trapping system, comprising a first cone mirror and a second cone mirror coaxially arranged with a laser beam propagating in a vertical direction, a first magnetic field coil pair and a second magnetic field coil pair, a quarter wave plate and a plane reflector below the quarter wave plate, wherein the first cone mirror and the second cone mirror have a reflective surface that is at an angle of 45° to the laser beam, the two coils in the first magnetic field coil pair are symmetrically placed on both sides of the center plane of the first cone mirror, the two coils in the second magnetic field coil pair are symmetrically placed on both sides of the center plane of the second cone mirror, the quarter wave plate and the plane reflector are symmetrically placed on both sides of the center plane of the second cone mirror, and the first cone mirror and the second magnetic field coil pair are symmetrically placed on both sides of the center plane of the second cone mirror. The normal line coincides and is coaxial with the laser beam; the laser beam is reflected by the first conical mirror to form two pairs of cooling lights propagating in opposite directions in the horizontal direction, and the laser beam is reflected by the plane mirror to form a pair of cooling lights propagating in opposite directions in the vertical direction. Together with the above two pairs of cooling lights, a total of three pairs of cooling lights and the first magnetic field coil pair realize the cooling and trapping of the first atomic group; the laser beam is reflected by the plane mirror to form a pair of cooling lights propagating in opposite directions in the vertical direction, and the laser beam transmitted through the first conical mirror will be reflected by the second conical mirror to form two pairs of cooling lights propagating in opposite directions in the horizontal direction. Together with the above pair of cooling lights, a total of three pairs of cooling lights and the second magnetic field coil pair realize the cooling and trapping of the second atomic group.

[0007] Furthermore, the first conic mirror and the second conic mirror are both hollow quadrangular pyramid or truncated pyramid corner conic mirrors with at least four reflecting surfaces, and the angle between the two opposing reflecting surfaces is 90°; the first conic mirror can reflect a laser beam with half power and transmit a laser beam with half power; the second conic mirror can reflect a laser beam with full power.

[0008] Furthermore, the diameter of the laser beam is not less than the length of the diagonal line of the axle, and acts on the first axle and the second axle in a suitable polarization state.

[0009] Furthermore, the laser beam propagates vertically from top to bottom or from bottom to top. According to the different propagation directions of the laser beam, the placement postures of the first prism, the second prism, the quarter-wave plate and the plane reflector can be adjusted.

[0010] Compared with the prior art, the technical solution of this application has the following beneficial technical effects: The present invention adopts a semi-transparent and semi-reflective corner cube and a fully reflective corner cube to realize the synchronous cooling and trapping of diatomic clusters in a single beam, which reduces the complexity of the system, solves the problem of poor consistency in trapping of diatomic clusters, and effectively improves the measurement sensitivity and accuracy of the atomic gravity gradiometer. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 A schematic diagram of the system structure of an embodiment of the present invention; Figure 2Schematic diagram of the structure of the corner cube in an embodiment of the present invention.

[0012] The reference numerals are: 101 - laser beam, 102 - first magnetic field coil pair, 103 - first axle, 104 - second magnetic field coil pair, 105 - second axle, 106 - quarter wave plate, 107 - plane reflector. DETAILED DESCRIPTION

[0013] In order to facilitate understanding of the present application, the present application will be described more fully below with reference to the relevant drawings. Embodiments of the present application are provided in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0014] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0015] It will be appreciated that spatial relationship terms such as "under," "beneath," "below," "under," "above," "above," etc., may be used herein to describe the relationship of an element or feature shown in the figures to other elements or features. It will be appreciated that, in addition to the orientations shown in the figures, spatial relationship terms also include different orientations of the device in use and operation. For example, if the device in the accompanying drawings is flipped, an element or feature described as "under other elements" or "under it" or "under it" will be oriented as being "above" the other elements or features. Thus, the exemplary terms "under" and "under" may include both upper and lower orientations. In addition, the device may also include additional orientations (e.g., rotated 90 degrees or other orientations), and the spatial descriptors used herein are interpreted accordingly.

[0016] When used herein, the singular forms "a", "an" and "the" may also include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include / comprise" or "have" etc. specify the presence of stated features, wholes, steps, operations, components, parts or combinations thereof, but do not exclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts or combinations thereof. Example 1

[0017] like Figure 1As shown, the present application provides a dual-atomic cluster synchronous cooling and trapping system based on a semi-transparent and semi-reflective corner cone mirror, including a laser beam 101, a first magnetic field coil pair 102, a first cone mirror 103, a second magnetic field coil pair 104, a second cone mirror 105, a quarter wave plate 106 and a plane reflector 107.

[0018] The laser beam 101 has a specific polarization state and propagates from top to bottom in the vertical direction. The first axle 103 and the second axle 105 are coaxial with the laser beam 101, and the reflection surfaces of the two axles form an angle of 45° with the propagation direction of the laser beam 101. The first axle 103 and the second axle 105 are both corner axles with at least four reflection surfaces, such as Figure 2 As shown, the angle between the two opposing reflection surfaces is 90°. The first axle mirror 103 can reflect the laser beam 101 with half power and transmit the laser beam 101 with half power, and the second axle mirror 105 can reflect the laser beam 101 with full power.

[0019] The diameter of the laser beam 101 is not less than the length of the diagonal of the first axle 103 and the second axle 105, and the laser beam 101 has been adjusted to a specific polarization state before interacting with the first axle 103 and the second axle 105. The placement of the first axle 103, the second axle 105, the quarter wave plate 106 and the plane reflector 107 is adjusted according to the different propagation directions of the laser beam 101.

[0020] The first coil pair 102 and the second coil pair 104 pass current to generate a magnetic field gradient. The two coils in the first magnetic field coil pair 102 are symmetrically placed on both sides of the center plane of the first conical mirror 103, and similarly, the two coils in the second magnetic field coil pair 104 are symmetrically placed on both sides of the center plane of the second conical mirror 105, and the normals of the quarter wave plate 106 and the plane reflector 107 coincide and are coaxial with the laser beam 101.

[0021] When cooling and trapping atoms, a laser beam 101 with a specific frequency, power and polarization state propagates from top to bottom in the vertical direction. The laser beam 101 first passes through the first conical mirror 103, where half of the power of the laser is reflected to form two pairs of cooling lights in the horizontal direction. The other half of the power of the laser is transmitted and continues to propagate downward. This part of the transmitted light is reflected by the second conical mirror 105, and two pairs of cooling lights are also formed in the horizontal direction. Finally, the laser beam 101 passes through the quarter-wave plate 106 and the plane reflector 107 to generate a reflected laser beam 101 with a polarization direction opposite to the propagation direction, which forms a pair of cooling lights in the vertical direction with the laser beam 101, and is used for cooling and trapping two groups of atoms at the same time. The cooling light pair formed above acts on the atoms, and combined with the action of the magnetic field coil pair, the synchronous cooling and trapping of two atomic groups with a single beam can be achieved.

[0022] Figure 21 is a schematic diagram of the structure of the corner cube in the embodiment, the first corner cube 103 has the same structure as the second corner cube 105, but the first corner cube 103 is a semi-transparent and semi-reflective corner cube, and the second corner cube 105 is a total reflection corner cube. The four reflection surfaces of the corner cube are all 45° to the axis, and the reflection surfaces facing each other are 90°. Example 2

[0023] In another embodiment of the present application, the laser beam 101 propagates from bottom to top, and other devices are placed accordingly to achieve synchronous cooling and trapping of diatomic clusters in a single beam. Both the first conical mirror 103 and the second conical mirror 105 are conical mirrors.

[0024] The above embodiments are only illustrative of the principles and effects of the present invention, as well as some embodiments of its application. For those skilled in the art, several modifications and improvements may be made without departing from the creative concept of the present invention, and all of these belong to the protection scope of the present invention.

Claims

1. A diatomic cluster synchronous cooling and trapping system, characterized in that: The invention comprises a first cone mirror (103) and a second cone mirror (105) which are coaxially arranged with a laser beam (101), a first magnetic field coil pair (102) and a second magnetic field coil pair (104), a quarter wave plate (106), and a plane reflector (107) behind the quarter wave plate (106), wherein the first cone mirror (103) and the second cone mirror (105) have reflective surfaces which form an angle of 45° with the laser beam (101), the two coils in the first magnetic field coil pair (102) are symmetrically arranged on both sides of the center plane of the first cone mirror (103), the two coils in the second magnetic field coil pair (104) are symmetrically arranged on both sides of the center plane of the second cone mirror (105), and the The normal lines of the quarter wave plate (106) and the plane reflector (107) coincide with each other and are coaxial with the laser beam (101); the laser beam (101) is reflected by the first conical mirror (103) to form two pairs of cooling lights propagating in opposite directions, and is reflected by the plane reflector (107) to form a pair of cooling lights propagating in opposite directions, which together with the two pairs of cooling lights and the first magnetic field coil pair (102) realize cooling and trapping of the first atomic group; the laser beam (101) transmitted through the first conical mirror (103) is reflected by the second conical mirror (105) to form two pairs of cooling lights propagating in opposite directions, which together with the pair of cooling lights and the second magnetic field coil pair (104) realize cooling and trapping of the second atomic group.

2. A diatomic cluster synchronous cooling and trapping system according to claim 1, characterized in that: The first conic mirror (103) and the second conic mirror (105) are both hollow quadrangular pyramid or truncated pyramid structure corner conic mirrors having at least four reflection surfaces, and the angle between the reflection surfaces facing each other is 90°; the first conic mirror (103) can reflect a laser beam with half power and transmit a laser beam with half power; and the second conic mirror (105) can reflect a laser beam with full power.

3. A diatomic cluster synchronous cooling and trapping system according to claim 1 or 2, characterized in that: The laser beam (101) has a diameter no less than the length of the diagonal line of the axle, and acts on the first axle (103) and the second axle (105) in a polarized state.

4. The diatomic cluster synchronous cooling and trapping system according to claim 3, characterized in that: The laser beam (101) propagates vertically from top to bottom or from bottom to top.

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