Atomic interferometer quantization axis magnetic field control device

Abstract

The application discloses an atomic interferometer quantumized axis magnetic field control device, which comprises an adjustable mirror, a vacuum cavity, a cold atom group, a first group of quantumized axis magnetic field coils, a second group of quantumized axis magnetic field coils, a third group of quantumized axis magnetic field coils, a mirror group and a coil control unit. The coil control unit controls the three groups of quantumized axis magnetic field coils to ensure that the quantumized axis magnetic field direction and the Raman light direction are always collinear in a dynamic environment, and then the atomic interference is completed. The size, direction and change frequency of the quantumized axis magnetic field generated by the layout mode of the three pairs of Helmholtz coils can be changed to adapt to the requirement that the Raman light direction of the atomic interferometer, the free falling direction of the cold atom group and the quantumized axis direction are parallel to each other. Meanwhile, the atomic cooling stage can also be used for the compensation of the geomagnetic field and the environmental stray magnetic field of the atomic interferometer in the atomic preparation stage.

Description

Technical Field

[0001] This invention relates to the field of quantum precision measurement technology, specifically to a quantum axis magnetic field control device for an atomic interferometer under dynamic conditions. Background Technology

[0002] In cold atom interference, in order for atoms to undergo specific Raman transitions in the interference region, a specific magnetic field strength is required to split the atomic magnetic level and ensure a uniform distribution to avoid the quantized axis magnetic field of the second-order Zeeman effect.

[0003] The quantized axial magnetic field in the atomic interference region needs to satisfy three necessary conditions: uniformity, stability, and parallelism with the Raman beam direction (the direction of gravity). Quantum precision measurement instruments based on atomic interference, such as cold atom clocks, atomic gravimeters, atomic gradiometers, and atomic gyroscopes, have been developed rapidly.

[0004] Taking atomic gravimeters as an example, static atomic gravimeters have demonstrated excellent performance. However, in dynamic environments, due to external interference such as vibration and tilt, the direction of the Raman beam and the direction of the quantized axis magnetic field will tilt angularly with the movement of the carrier, resulting in an angle between them. This makes it impossible to acquire and measure gravity information. Therefore, in dynamic environments, ensuring the parallelism between the Raman beam direction and the quantized axis magnetic field, and ensuring the stability and uniformity of the quantized axis magnetic field, are necessary conditions for atomic interferometry.

[0005] Existing technologies typically employ active and passive vibration damping platforms, along with gyro-stabilized platforms, in the sensitive unit of an atomic interferometer to suppress interference from the external environment, thereby maintaining the sensitive unit's static state and achieving the effect of aligning the Raman beam with the quantization axis. However, such vibration damping platforms not only have a time delay in suppressing vibrations and limited suppression effectiveness, reducing data output rate, but also increase the size and weight of the atomic interferometer. Summary of the Invention

[0006] The purpose of this invention is to address the aforementioned problems of existing atomic interferometers in dynamic environments by providing a quantum axis magnetic field control device in which both the direction and magnitude of the quantum axis magnetic field are adjustable. This solves the technical problem that the direction of atomic motion (gravity direction), the Raman light pointing direction, and the direction of the quantum axis magnetic field are not coincident or parallel in dynamic environments.

[0007] To achieve the above objectives, the technical solution adopted by this invention to solve its technical problem is as follows: a quantum axis magnetic field control device for an atomic interferometer, comprising a vacuum cavity for providing a falling channel for cold atom clusters and a transmission channel for Raman laser beams, a set of reflectors disposed below the vacuum cavity, and an adjustable reflector disposed directly above the vacuum cavity. The normal direction of the adjustable reflector is at a 45-degree angle to the central axis of the vacuum cavity, and the angle can be adjusted at any time according to the tilt of the interferometer to ensure that the direction of the Raman laser beam is collinear with the free falling direction of the cold atom clusters. The normal direction of the reflector set is parallel to the central axis of the vacuum cavity and is used to reflect the Raman laser beam to form two opposing and overlapping Raman beams for interfering with the cold atom clusters. The device also includes a coil control unit and a first set of quantum axis magnetic field coils, a second set of quantum axis magnetic field coils, and a third set of quantum axis magnetic field coils connected to the coil control unit. The coil control unit generates three adjustable coils. The system includes a driving current, with the normal direction of the reflector group parallel to the central axis of the vacuum cavity, used to reflect the Raman laser beam to form two opposing and overlapping Raman beams for interference manipulation of cold atomic clusters. It also includes a coil control unit and three sets of quantized axis magnetic field coils connected to the control unit. The coil control unit generates three adjustable alternating currents with adjustable magnitude, frequency, and phase difference. The first set of quantized axis magnetic field coils is located in the atomic interference region within the vacuum cavity, with its normal direction perpendicular to the central axis of the vacuum cavity. The second set of quantized axis magnetic field coils is located in the atomic interference region within the vacuum cavity, with its normal direction perpendicular to the central axis of the vacuum cavity and also perpendicular to the normal direction of the first set of quantized axis magnetic field coils. The third set of quantized axis magnetic field coils is located in the atomic interference region within the vacuum cavity, with its normal direction parallel to the central axis of the vacuum cavity and perpendicular to the normal directions of the first and second sets of quantized axis magnetic field coils.

[0008] The aforementioned atomic interferometer quantized axis magnetic field control device employs a Helmholtz coil layout for its first, second, and third sets of quantized axis magnetic field coils.

[0009] The aforementioned atomic interferometer quantized axis magnetic field control device has a first set of quantized axis magnetic field coils located outside the second set of quantized axis magnetic field coils, and the second set of quantized axis magnetic field coils located outside the third set of quantized axis magnetic field coils.

[0010] The aforementioned quantum axis magnetic field control device for an atomic interferometer has a mirror assembly surface coated with a 1 / 4 dielectric film to change the polarization direction of the Raman beam.

[0011] The aforementioned quantum axis magnetic field control device for an atomic interferometer uses non-magnetic materials, such as titanium and glass, in its vacuum chamber, and the vacuum level of the vacuum chamber is better than 10E-7 Pa.

[0012] This invention employs a three-pair Helmholtz coil arrangement to generate the quantized axis magnetic field during atomic interference. Compared to existing technologies, the advantages of this invention are as follows: 1. The present invention employs a layout of three pairs of Helmholtz coils to generate a quantized axis magnetic field whose magnitude, direction, and frequency of change can all be altered to adapt to the requirement that the direction of the Raman light of the atomic interferometer, the direction of the free fall of cold atom clusters, and the direction of the quantized axis be parallel in a dynamic environment. 2. The quantized axial magnetic field generated by the three Helmholtz coils proposed in this invention can also be used to compensate for geomagnetic and environmental stray magnetic fields in the vacuum cavity of the atomic interferometer during the cold atom preparation stage. By switching between the atomic cooling and atomic interference stages through the coil control unit, the bias coil and compensation coil in the existing atomic interferometer are separated and reduced to only one type of coil. This not only reduces the design and installation difficulty, but also reduces the weight and volume of the atomic interferometer to a certain extent, making it more suitable for dynamic environments. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the adjustable quantized axial magnetic field device of the present invention; Figure 2 This is a projection diagram of the three sets of quantized axial magnetic field structures of the present invention.

[0014] The reference numerals in the attached figures are as follows: 101—Raman laser beam, 201—Adjustable mirror, 202—Mirror group, 301—Vacuum cavity, 401—First group of quantized axis magnetic field coils, 402—Second group of quantized axis magnetic field coils, 403—Third group of quantized axis magnetic field coils, 501—Cold atom cluster, 601—Coil control unit. Detailed Implementation

[0015] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0016] Reference Figure 1As shown, this invention discloses a quantum axis magnetic field control device for an atomic interferometer in a dynamic environment, which solves the technical problem that existing atomic interferometers cannot maintain the coincidence of the quantum axis magnetic field, Raman light direction, and atomic free fall direction (gravity direction) when measuring in a dynamic environment, thus making it impossible to perform measurements; it includes an adjustable reflector 201, a vacuum cavity 301, a cold atom cluster 501, a first set of quantum axis magnetic field coils 401, a second set of quantum axis magnetic field coils 402, a third set of quantum axis magnetic field coils 403, a reflector group 202, and a coil control unit 601.

[0017] The vacuum cavity 301 is made of non-magnetic materials, such as titanium and glass, and has a vacuum level better than 10E-7Pa. It is used to provide a falling channel for cold atom clusters 501 and a transmission channel for Raman laser beam 101.

[0018] The adjustable reflector 201 is positioned directly above the vacuum cavity 301, with its normal direction at a 45-degree angle to the central axis of the vacuum cavity 301. This angle can be adjusted at any time according to the tilt of the interferometer to ensure that the Raman laser beam 101 is collinear with the free-falling direction of the cold atom cluster 501. This is used to refract the incident Raman beam into the vacuum cavity 301. The adjustable reflector 201 adjusts the direction of the Raman light according to the input position signal, so that the direction of the Raman light is always collinear with the free-falling direction of the cold atom cluster 501 in a dynamic environment.

[0019] The reflector group 202 is disposed below the vacuum cavity 301, with its normal direction parallel to the central axis of the vacuum cavity 301. It is used to reflect the Raman laser beam 101 to form opposing and overlapping Raman laser beams 101 to perform interference operation on the cold atom cluster 501.

[0020] The first set of quantized axis magnetic field coils 401, the second set of quantized axis magnetic field coils 402, and the third set of quantized axis magnetic field coils 403 are used to provide quantized axis magnetic fields during the atomic interference stage and to provide compensation magnetic fields during the atomic cooling stage, so as to eliminate the influence of the geomagnetic field and the surrounding stray magnetic field on the cold atom cluster 501.

[0021] The coil control unit 601 is used to control the driving and control of the three sets of Helmholtz coils, for the compensation magnetic field in the atomic cooling stage and for the quantized axis magnetic field in the atomic interference stage.

[0022] Figure 2 This is a schematic diagram showing the specific nesting arrangement of the three sets of Helmholtz coils in the quantumized axial magnetic field control device of the present invention.

[0023] The first group of quantized axis magnetic field coils 401, the second group of quantized axis magnetic field coils 402, and the third group of quantized axis magnetic field coils 403 are orthogonal to each other in pairs. Specifically, the first group of quantized axis magnetic field coils 401 is located in the atomic interference region inside the vacuum cavity 301, with its normal direction perpendicular to the central axis of the vacuum cavity 301. The second group of quantized axis magnetic field coils 402 is located in the atomic interference region inside the vacuum cavity 301, with its normal direction perpendicular to the central axis of the vacuum cavity 301 and perpendicular to the normal direction of the first group of quantized axis magnetic field coils 401. The third group of quantized axis magnetic field coils 403 is located in the atomic interference region inside the vacuum cavity 301, with its normal direction parallel to the central axis of the vacuum cavity 301 and perpendicular to the normal directions of the first group of quantized axis magnetic field coils 401 and the second group of quantized axis magnetic field coils 402.

[0024] Furthermore, the first set of quantized axis magnetic field coils 401 is positioned outside the second set of quantized axis magnetic field coils 402, and the second set of quantized axis magnetic field coils 402 is positioned outside the third set of quantized axis magnetic field coils 403. The three sets of coils are nested together to generate a uniform magnetic field.

[0025] The coil control unit 601 is used to control the intensity of the current in the first group of quantized axis magnetic field coils 401, the second group of quantized axis magnetic field coils 402 and the third group of quantized axis magnetic field coils 403, thereby controlling the magnitude, direction and frequency of the quantized axis magnetic field intensity.

[0026] The first group of quantized axial magnetic field coils 401, the second group of quantized axial magnetic field coils 402, and the third group of quantized axial magnetic field coils 403 all adopt the layout of Helmholtz coils.

[0027] The surface of the mirror assembly 202 is coated with a 1 / 4 dielectric film to change the polarization direction of the Raman beam.

[0028] The vacuum chamber 301 is made of non-magnetic materials, such as titanium and glass, and the vacuum degree of the vacuum chamber 301 is better than 10E-7Pa.

[0029] In the specific implementation of the quantum axis magnetic field control device of the present invention: the cold atom cluster 501 undergoes free fall under the action of gravity, and the falling direction coincides with the direction of gravitational acceleration; the vacuum cavity 301 is used as the transmission channel between the falling channel of the cold atom cluster 501 and the transmission channel of the Raman laser beam 101; the Raman laser beam 101 and the cold atom cluster 501 undergo two-photon stimulated Raman pulse interaction, manipulating the atoms to transfer energy levels and causing changes in their internal states, while simultaneously transferring the energy of the photons to the atoms, causing changes in the external state velocity of the atoms, thereby causing beam splitting, deflection and beam recombination, and completing interference.

[0030] Under the influence of gravity, the cold atom cluster 501 undergoes free fall, with its falling direction coinciding with the direction of gravitational acceleration. The vacuum cavity 301 serves as a channel for transmitting the falling cold atom cluster 501 and the Raman laser beam 101. The Raman laser beam 101 interacts with the cold atom cluster 501 through a two-photon stimulated Raman pulse, manipulating the atoms to shift energy levels, causing changes in their internal states. Simultaneously, the energy of the photons is transferred to the atoms, altering their external velocity and resulting in beam splitting, deflection, and recombining, thus completing interference. In this embodiment, the atomic interferometer is in a static or dynamic environment. During the atomic cooling stage, the coil control unit 601 switches to the DC section to compensate for the stray magnetic field around the cold atom cluster 501, thereby trapping the cold atom cluster 501 in the magneto-optical trap. During the atomic interference stage, the coil control unit 601 continuously changes the current intensity to generate a vector quantized axis magnetic field with adjustable magnetic field intensity in any direction.

[0031] The adjustment method is as follows: the coil control unit 601 receives the adjustment angle input by the adjustable reflector 201, and adjusts the current of different magnitudes and intensities between the first group of quantized axis magnetic field coils 401, the second group of quantized axis magnetic field coils 402, and the third group of quantized axis magnetic field coils 403 to ensure that the direction of the quantized axis magnetic field always coincides with the direction of the Raman light.

[0032] The above embodiments are merely illustrative of the principles and effects of the present invention, as well as some of the application examples. For those skilled in the art, various modifications and improvements can be made without departing from the inventive concept of the present invention, and these all fall within the protection scope of the present invention.

Claims

1. A quantum axis magnetic field control device for an atomic interferometer, characterized in that: The system includes a vacuum cavity (301) for providing a falling channel for cold atom clusters (501) and a transmission channel for Raman laser beams (101), a mirror assembly (202) disposed below the vacuum cavity (301), and an adjustable mirror (201) disposed directly above the vacuum cavity (301). The normal direction of the adjustable mirror (201) is at a 45-degree angle to the central axis of the vacuum cavity (301), and the normal direction of the mirror assembly (202) is parallel to the central axis of the vacuum cavity (301). It also includes a coil control unit (601) and a first set of quantized axial magnetic field coils (401), a second set of quantized axial magnetic field coils (402), and a third set of quantized axial magnetic field coils (403) connected to the coil control unit (601). The coil control unit (601) generates three paths of varying magnitudes. Adjustable coil drive current; the first set of quantized axis magnetic field coils (401) is disposed in the atomic interference region inside the vacuum cavity (301), and the normal direction is perpendicular to the central axis of the vacuum cavity (301); the second set of quantized axis magnetic field coils (402) is disposed in the atomic interference region inside the vacuum cavity (301), and the normal direction is perpendicular to the central axis of the vacuum cavity (301) and perpendicular to the normal direction of the first set of quantized axis magnetic field coils (401); the third set of quantized axis magnetic field coils (403) is disposed in the atomic interference region inside the vacuum cavity (301), and the normal direction is parallel to the central axis of the vacuum cavity (301) and perpendicular to the normal directions of the first set of quantized axis magnetic field coils (401) and the second set of quantized axis magnetic field coils (402).

2. The quantum axis magnetic field control device for an atomic interferometer according to claim 1, characterized in that, The first group of quantized axial magnetic field coils (401), the second group of quantized axial magnetic field coils (402) and the third group of quantized axial magnetic field coils (403) all adopt Helmholtz coils.

3. The quantum axis magnetic field control device for an atomic interferometer according to claim 1, characterized in that, The first group of quantized axis magnetic field coils (401) is located outside the second group of quantized axis magnetic field coils (402), and the second group of quantized axis magnetic field coils (402) is located outside the third group of quantized axis magnetic field coils (403).

4. A quantum axis magnetic field control device for an atomic interferometer according to claim 1, 2, or 3, characterized in that, The surface of the mirror assembly (202) is coated with a 1 / 4 dielectric film.

5. The quantum axis magnetic field control device for an atomic interferometer according to claim 4, characterized in that, The vacuum chamber (301) is made of titanium or glass and has a vacuum level better than 10E-7Pa.

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