CN111897024B - Cold atom gravimeter and detection method - Google Patents
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- CN111897024B CN111897024B CN202010511642.3A CN202010511642A CN111897024B CN 111897024 B CN111897024 B CN 111897024B CN 202010511642 A CN202010511642 A CN 202010511642A CN 111897024 B CN111897024 B CN 111897024B
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Abstract
The invention discloses a cold atom gravimeter and a detection method, relates to the technical field of cold atom gravity detection, and aims to solve the technical problem that the sensitivity of the existing cold atom gravimeter is difficult to improve. The method comprises the following steps: preparing a ground state cold radical moving vertically upwards; applying two-photon stimulated Raman pulse vertically upwards to the ground state cold radicals, dividing the ground state cold radicals into two cold radicals with different superposition states and different speeds, and splitting the beams to move on two paths; applying two-photon stimulated Raman pulses to the two cold radicals, inverting the internal states of the two cold radicals, and converting the internal states into movement amounts; trapping the two cold atomic groups with reversed states until the two cold atomic groups fall freely; applying two-photon stimulated Raman pulses to the two descending cold radicals again, and superposing and combining the internal states of the two cold radicals to enable the two cold radicals to generate interference; interference fringes of the cold radicals subjected to interference are collected.
Description
Technical Field
The invention relates to the technical field of cold atom gravity detection, in particular to a cold atom gravimeter and a detection method.
Background
At present, a cold atom gravimeter mainly extracts gravity acceleration information of a position in a gravity field by utilizing the relationship between gravity acceleration and transition probability in a cold atom group internal state in a coherent process of the cold atom group based on a substance wave interference principle. The beam splitting, deflection and beam combination of the cold atomic groups in the movement in the vertical direction are realized through the two-photon stimulated Raman pulse, the interference effect of the cold atomic groups on two paths is realized, and finally, the gravity acceleration information is extracted from the interference fringes of the cold atomic groups.
The above scheme can measure the gravitational acceleration, and the phase accumulated by the cold radicals on the two interference paths directly determines the measured gravitational acceleration, i.e. the disturbance of the phase can cause the measurement noise of the gravitational acceleration, such as the phase noise of the raman optical frequency lock, the vibration noise, etc., and the response of the gravitational acceleration to the phase noise is called the sensitivity of the gravimeter. However, the phases of cold radicals accumulated on the two interference paths only contain laser phase information, and the phase of free evolution time of atoms is ignored. In order to improve the sensitivity, the sensitivity needs to be improved by increasing the height of the free falling body of the cold atomic group, namely, the gravity meter is large in size and weight and difficult to realize by the method.
Disclosure of Invention
The invention aims to provide a detection method of a cold atom gravimeter, which is used for improving the total phase of cold atom groups in the cold atom gravimeter and solving the technical problem that the sensitivity is difficult to improve in the prior art.
In order to achieve the above purpose, the invention provides the following technical scheme:
a cold atom gravimeter comprising: the ground state cold atom preparation device, the signal collector, the optical lattice component, the first Raman beam laser and the second Raman beam laser are arranged in the vacuum cavity;
the ground state cold atom preparation device is used for preparing ground state cold atom groups moving vertically upwards;
the first Raman beam laser is used for applying a first two-photon stimulated Raman pi/2 pulse to the ground state cold atomic group, dividing the ground state cold atomic group into two cold atomic groups in a superposition state and different in speed, and splitting the two cold atomic groups into two paths to move; the two-photon stimulated Raman pi/2 pulse is applied to the two descending cold radicals again, and the internal states of the two cold radicals are superposed and combined to enable the two cold radicals to generate interference;
the second Raman beam laser is used for applying two-photon stimulated Raman pi pulses to the two cold atomic groups entering the free falling body area, reversing the internal states of the two cold atomic groups and converting the internal states into movement amounts;
the optical lattice component is used for trapping the two cold atomic groups with inverted states, and limiting the spatial displacement and diffusion of the two cold atomic groups until the two cold atomic groups fall freely;
and the signal collector is used for collecting interference fringes of the interfered cold atomic groups.
Compared with the prior art, the cold atom gravimeter provided by the invention can realize the periodic two-photon Raman pulse action and the photo-lattice trapping process by repeating the laser cooling of the magneto-optical trap and the upward polishing of the laser beam in the periodic time sequence operation process, so that interference fringes containing gravity acceleration information are generated, and the periodic measurement of the gravity acceleration is realized. Meanwhile, the process effectively prolongs the interaction time of the cold atoms and the gravity field, namely, the aim of increasing the cold atom accumulated phase is achieved, and the ratio of the accumulated phase to the gravity acceleration is greatly improved, namely, the aim of improving the measurement sensitivity of the gravity acceleration is achieved. The device not only improves the total phase of cold atomic groups in the cold atomic gravimeter and solves the problems that the sensitivity is difficult to improve and the like in the prior art, but also has simple structure, easy realization, low material and processing cost, reasonable method and easy operation.
The invention also provides a detection method of the cold atom gravimeter, which comprises the following steps:
preparing ground state cold radicals moving vertically upwards;
applying a first two-photon stimulated Raman pi/2 pulse to the ground state cold radicals, dividing the ground state cold radicals into two cold radicals in a superposition state and at different speeds, and splitting the two cold radicals into two paths to move;
applying two-photon stimulated Raman pi pulses to the two cold radicals entering the free falling body area, inverting the internal states of the two cold radicals, and transferring the momentum of the two cold radicals;
trapping the two cold atomic groups with reversed internal states, and limiting the spatial displacement and diffusion of the two cold atomic groups until the two cold atomic groups fall freely;
applying a two-photon stimulated Raman pi/2 pulse to the two descending cold radicals again, and superposing and combining the internal states of the two cold radicals to enable the two cold radicals to generate interference;
interference fringes of the cold radicals subjected to interference are collected.
Compared with the prior art, the detection method of the cold atom gravimeter provided by the invention has the same beneficial effects as the ultra-long free evolution time cold atom frequency standard device in the technical scheme, and the description is omitted here.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention and not to limit the invention. In the drawings:
FIG. 1 is a schematic structural diagram of a cold atom gravimeter according to an embodiment of the present invention;
FIG. 2 is a schematic flow chart of a cold atom gravimeter detection method according to an embodiment of the present invention;
FIG. 3 is a timing diagram illustrating the operation of a cold atom gravimeter according to an embodiment of the present invention.
Reference numerals:
1-atom source, 2-vacuum chamber, 3-laser, 4-polishing beam, 5-magneto-optical trap cooling component, 6-state selection chamber, 7-first Raman beam laser, 71-second Raman beam laser, 8-first Raman beam, 81-second Raman beam, 9-signal collector, 10-optical lattice component, 11-cold atomic group, 12-free falling body area and 13-device axial central line.
Detailed Description
In order to make the technical problems, technical solutions and advantageous effects to be solved by the present invention more clearly apparent, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or be indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or be indirectly connected to the other element.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise. The meaning of "a number" is one or more unless specifically limited otherwise.
In the description of the present invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", and the like indicate orientations or positional relationships based on orientations or positional relationships shown in the drawings, which are merely for convenience of description and simplification of description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed in a particular orientation, and operate, and thus, should not be construed as limiting the present invention.
In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or may be connected through the use of two elements or the interaction of two elements. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
Referring to fig. 1 in detail, the present invention provides a cold atom gravimeter, comprising: a ground state cold atom preparation device, a signal collector 9, an optical lattice component 10, a first raman beam laser 7, and a second raman beam laser 71, which are disposed in the vacuum chamber 2;
a ground state cold atom preparing device for preparing ground state cold atom group moving vertically upwards;
the first Raman beam laser 7 is used for applying a first two-photon stimulated Raman pi/2 pulse to the ground state cold radicals, dividing the ground state cold radicals into two cold radicals 11 in a superposition state and at different speeds, and splitting the two cold radicals 11 into two paths to move; the two-photon stimulated Raman pi/2 pulse is applied to the two descending cold radicals 11 again, the internal states of the two cold radicals 11 are superposed and combined, and the two cold radicals 11 are interfered;
a second raman beam laser 71 which applies two-photon stimulated raman Π pulses to the two cold radicals 11 entering the free fall region 12, inverts internal states of the two cold radicals 11, and shifts an amount of movement;
the photo-lattice component 10 traps the two cold atomic groups 11 with the inverted internal states, and limits the spatial displacement and diffusion of the two cold atomic groups 11 until the two cold atomic groups fall freely;
the signal collector 9 collects interference fringes of the cold radicals 11 that interfere with each other.
In the specific implementation:
wherein, an atom source 1 of the cold atom gravimeter provides cold atoms, and a vacuum cavity 2 provides a high vacuum environment for atom storage, so as to avoid the interference of redundant impurity gas to the atoms; the magneto-optical trap cooling assembly 5 can cool the cold atom temperature to uK magnitude, and the preparation of the cold atom group 11 is completed; the state selection cavity 6 provides a microwave oscillation field corresponding to the ground state energy level of the cold atomic group 11, and the cold atomic group 11 is prepared to a corresponding low energy state through interaction with the cold atomic group 11; the laser 3 generates an upper polishing beam 4, and the upper polishing beam 4 vertically casts the prepared cold atomic groups 11 to enable the prepared cold atomic groups to obtain a certain speed macroscopically, so that the cold atomic groups 11 can move upwards and enter the optical crystal lattice assembly 10; the first raman beam laser 7 and the second raman beam laser 71 respectively generate raman laser beams, the optical frequency difference of the two raman laser beams is equal to the atomic ground state energy level splitting distance, the propagation directions of the two raman laser beams are opposite in the vertical direction, the raman laser beams and the cold atomic groups 11 can perform a two-photon stimulated raman pulse effect, the effect can not only control the transfer of atoms on the energy level to change the internal state of the atoms, but also can transfer the momentum of photons to the atoms, and the change of the external state speed of the photons further causes beam splitting, deflection and beam combination; the signal collector 9 can detect the energy state population condition of the cold atomic group 11; the optical lattice component 10 is composed of laser beams with specific wavelengths according to interference atoms, the potential energy at the wave crest is high, the potential energy at the wave trough is low, and the cold atomic groups 11 can be imprisoned for a long time through the potential energy difference between the wave crest and the wave troughUp to 10 in photonic lattice assembly 10 1 And the magnitude of s limits the spatial displacement and diffusion of the optical lattice component 10, in the trapping process of the optical lattice component, the phase difference introduced by the free evolution of the cold atomic groups 11 under the action of the gravity field can be calculated through the Fisman path integration, the classical acting amount on the two paths can be calculated, the Lagrange amount is added, and the accumulated phase difference of the atoms is increased.
The cold atom gravimeter can realize the periodic two-photon Raman pulse action and the trapping process of the optical lattice component by repeating laser cooling of the magneto-optical trap and upward polishing of a laser beam in the periodic time sequence operation process, and then generates interference fringes containing gravity acceleration information, namely, the periodic measurement of the gravity acceleration is realized. Meanwhile, the interaction time of the cold atoms and the gravity field is effectively prolonged, namely, the aim of increasing the cold atom accumulation phase is achieved, and the ratio of the accumulation phase to the gravity acceleration is greatly improved, namely, the aim of improving the measurement sensitivity of the gravity acceleration is achieved. The device has the advantages of simple structure, easy realization, low material and processing cost, reasonable method and easy operation.
As an embodiment, the ground state cold atom preparation device includes:
a cold atom producing device for producing high-energy-state cold radicals having a vertically upward velocity;
and the state selection cavity 6 is used for providing a microwave oscillating field for the high-energy state cold atomic groups and preparing the high-energy state cold atomic groups into ground state cold atomic groups.
The high-energy-state cold atomic groups in the upward motion state can be subjected to state selection in the state selection cavity 6, the state selection cavity 6 can provide a microwave oscillation field corresponding to the cold atom ground state energy level, cold atoms are prepared to be in a corresponding low-energy state through interaction with the cold atoms, and state population of the required energy level is completed.
As an embodiment, the cold atom production apparatus includes:
an atom source 1 for providing atoms;
the magneto-optical trap cooling assembly 5 is used for cooling the atoms provided by the atom source 1 to finish the preparation of the cold atomic group 11;
and the laser 3 is used for projecting the cold atomic group 11 in the vertical direction, providing the moving speed in the vertical direction for the static cold atomic group and converting the static cold atomic group into the high-energy-state cold atomic group.
Wherein the atom source 1 provides cold atoms, and the vacuum cavity 2 provides a high vacuum environment for atom storage, so that the interference of redundant impurity gas to the atoms is avoided; the magneto-optical trap cooling assembly 5 consists of 6 beams of laser and an anti-Helmholtz coil, and can cool the atomic temperature to uK magnitude order to complete the preparation of the cold atomic group 11; the laser 3 generates an upper polishing beam 4, and the upper polishing beam 4 vertically casts the prepared cold radicals 11 to obtain a certain speed macroscopically, so that the cold radicals 11 can move upwards to pass through the free falling body region 12 along the axial center line 12 of the device and enter the optical crystal lattice component 10. Under the action of the polishing beam 4 on the laser 3, the preparation of cold atoms from static state to high energy state is realized.
In one embodiment, the second raman beam laser 71, the optical lattice assembly 10, the phase selection chamber 6, the magneto-optical trap cooling assembly 5, the first raman beam laser 7, and the laser 3 are sequentially disposed from top to bottom along the axial centerline 12 of the vacuum chamber 2.
The second raman beam laser 71, the optical lattice assembly 10, the phase selection chamber 6, the magneto-optical trap cooling assembly 5, the first raman beam laser 7 and the laser 3 which are arranged along the axial center line 12 of the vacuum chamber 2 ensure that the cold atomic group 11 can move upwards and/or downwards along the axial center line 12, and ensure the accuracy of the final detection data.
Further, a signal collector is disposed between the magneto-optical trap cooling assembly and the phase selection cavity on one side of the axial centerline.
The signal collector arranged between the magneto-optical trap cooling assembly and the state selecting cavity can better collect signals, and the collected signals are ensured to be irradiated by the first Raman beam laser and the second Raman beam laser.
As an implementation example, the magneto-optical trap cooling assembly 5 comprises an anti-helmholtz coil and 6 lasers, the center line of the vacuum chamber 2 passes through the center of the anti-helmholtz coil, and the 6 lasers are uniformly distributed around the anti-helmholtz coil.
6 even settings of beam bundle are at anti Helmholtz coil, have ensured the cooling effect of magneto-optical trap cooling module 5 to the atom, can reduce the atom temperature to the uK order of magnitude, have guaranteed to accord with the preparation of temperature condition cold atom group 11.
As one possible embodiment, the optical frequency difference of the raman laser beams emitted by the first raman beam laser 7 and the second raman beam laser 71 is equal to the atomic ground state level splitting pitch.
The raman laser beams emitted by the first raman beam laser 7 and the second raman beam laser 71 can perform a two-photon stimulated raman pulse action with cold atoms, which not only can manipulate the atoms to shift in energy level to change their internal states, but also can transfer the momentum of the photons to the atoms, and the external state velocity changes to split, deflect and combine the beams. The optical frequency difference is equal to the two Raman laser beams at the atomic ground state energy level splitting interval, so that the total phase obtained by the atoms in the interference fringes of the two cold atomic groups 11 contains two kinds of phase information, namely the phase generated by the interaction of the Raman pulse and the cold atoms and the phase generated when the cold atomic groups 11 freely evolve in the optical crystal lattice, and the two phases are in positive correlation with the gravity acceleration.
Referring to fig. 2 in detail, the present invention further provides a method for detecting a cold atom gravimeter, in which the method uses a cold atom gravimeter, including:
preparing a ground state cold radical moving vertically upwards;
applying a first two-photon stimulated Raman pi/2 pulse to the ground state cold radicals, dividing the ground state cold radicals into two cold radicals in a superposition state and with different speeds, and splitting the two cold radicals into two paths to move;
applying two-photon stimulated Raman pi pulses to the two cold radicals entering the free falling body area, inverting the internal states of the two cold radicals, and transferring the momentum of the two cold radicals;
trapping the two cold atomic groups with reversed internal states, and limiting the spatial displacement and diffusion of the two cold atomic groups until the two cold atomic groups fall freely;
applying a two-photon stimulated Raman pi/2 pulse to the two descending cold radicals again, and superposing and combining the internal states of the two cold radicals to enable the two cold radicals to generate interference;
interference fringes of the cold radicals subjected to interference are collected.
As an embodiment, the preparation of the ground-state cold radicals moving vertically upward specifically includes:
preparing high-energy state cold atomic groups with vertical upward speed;
and providing a microwave oscillating field for the high-energy state cold atomic groups, and preparing the high-energy state cold atomic groups into ground state cold atomic groups.
The high-energy-state cold atomic group in the upward motion state can be subjected to state selection in the state selection cavity, the state selection cavity can provide a microwave oscillation field corresponding to the cold atom ground state energy level, cold atoms are prepared to corresponding low energy states through interaction with the cold atoms, and state population of required energy levels is completed.
As an embodiment, the preparation of high energy state cold atomic group with vertical upward velocity includes:
cooling the provided atoms to finish the preparation of cold atomic groups;
and (3) projecting the cold atomic groups in the vertical direction, providing a moving speed in the vertical direction for the static cold atomic groups, and converting the static cold atomic groups into high-energy-state cold atomic groups.
Wherein the atom source provides cold atoms, and the vacuum cavity provides a high vacuum environment for atom storage, so that the interference of redundant impurity gas to atoms is avoided; the magneto-optical trap cooling assembly consists of 6 beams of laser and an anti-Helmholtz coil, and can cool the atomic temperature to uK magnitude order to complete the preparation of cold atomic groups; the laser generates an upper polishing beam, and the upper polishing beam casts the prepared cold atomic groups in the vertical direction to enable the cold atomic groups to obtain a certain speed macroscopically, so that the cold atomic groups can move upwards to pass through a free falling body area along the axial center line of the device and enter the optical lattice assembly. Under the action of the polishing beam on the laser, the preparation from the static cold atomic group to the high-energy state cold atomic group is realized.
FIG. 3 is a schematic diagram showing the operation timing sequence of the cold atom gravimeter of the present invention, wherein T 1 Cooling time for magneto-optical trap, T 2 For a selected state time, T 3 For the first two-photon stimulated Raman pi/2 pulse action time, T 4 For the time of up-throwing through the free-fall zone, T 5 For two-photon stimulated Raman pi pulse action time, T 6 For confinement time in the photo cell, T 7 Time for falling through free fall zone, T 8 For the second two-photon stimulated Raman II/2 pulse action time, T 9 For detecting time, T C Is the run cycle.
The specific time sequence execution steps are as follows:
according to the running period T of the gravimeter C First, the cooling time T of the component is cooled in the magneto-optical trap 1 In the device, a magneto-optical trap cooling assembly cools atoms to a uK magnitude to prepare cold atomic groups, and the cold atomic groups obtain a certain macroscopic longitudinal speed and move upwards under the action of an upward polishing beam; the cold atomic group in the upward motion state passes through the state selection time T in the state selection cavity 2 Then completing the state population of the required energy level, and then T 3 Carrying out first two-photon stimulated Raman pi/2 pulse action with a first Raman laser beam, wherein the pi/2 pulse action can divide cold radicals initially in a ground state into two cold radicals in a superposed state, the two cold radicals have different speeds, and the two cold radicals are gradually split into two cold radicals to move in two paths; time T of upward throwing through free falling body area 4 Then, the two-photon stimulated Raman pi pulse action is carried out with a second Raman laser beam again, and the interaction time is T 5 The pi pulse effect will make the internal states of the two cold radicals completely reverse, and the momentum will also be transferred, i.e. the path is deflected; two cold radicals on the two paths after deflection will reach the peak and be trapped by the photo-lattice assembly, where the trapping time is T 6 The internal states of cold radicals in the caged state will be unaffectedThe external interference enters a free evolution stage, and the cold atomic groups have no heat diffusion effect; after the trapping process of the photo-lattice assembly is finished, the cold atomic groups begin to fall freely under the action of gravity, and in the falling process, the cold atomic groups fall through the free falling body area for the same time T as the time T of the upward throwing 7 Then, the cold radicals on both paths will be at T 8 Performing a second two-photon stimulated Raman pi/2 pulse action with the first Raman laser beam, wherein the pi/2 pulse action can superpose the internal states of the two cold atomic groups on the two paths again and combine the two cold atomic groups to enable the two cold atomic groups to interfere; the interference fringe at the detection time T 9 Detection is performed by a signal collector. The total phase obtained by the cold atomic groups in the interference fringes comprises two kinds of phase information, namely a phase generated by the interaction of Raman pulses and atoms and a phase generated when the cold atomic groups freely evolve in an optical lattice, wherein the two kinds of phase information are positively correlated with the gravity acceleration. That is, the total phase obtained by the atoms is in positive correlation with the gravity acceleration, and the gravity acceleration information can be extracted by fitting the interference fringes of the cold radicals to obtain the total phase of the cold radicals. In the whole process, the method effectively and simultaneously realizes the stimulated Raman transition of the cold radicals in the free falling body and the free evolution of the cold radical phase in the optical lattice by utilizing the two-photon Raman pulse effect and the optical lattice trapping technology, effectively prolongs the interaction time of the cold radicals and the gravitational field, and realizes the purpose of increasing the cold radical phase. The cold atomic group interference fringes obtained by the method simultaneously comprise phases generated by interaction of the Raman pulse and the cold atomic groups and phases of the cold atomic groups when the cold atomic groups freely evolve in the optical crystal lattices, and gravity acceleration information can be extracted by fitting the interference fringes of the cold atomic groups.
In the foregoing description of embodiments, the particular features, structures, materials, or characteristics may be combined in any suitable manner in any one or more embodiments or examples.
The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all the changes or substitutions should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.
Claims (10)
1. A cold atom gravimeter comprising: the device comprises a ground state cold atom preparation device, a signal collector, an optical lattice component, a first Raman beam laser and a second Raman beam laser which are arranged in a vacuum cavity;
the ground state cold atom preparation device is used for preparing ground state cold atom groups moving vertically upwards;
the first Raman beam laser applies vertical and upward two-photon stimulated Raman pulses to the ground state cold radicals, divides the ground state cold radicals into two cold radicals in a superposed state and at different speeds, and splits the two cold radicals into two paths to move; the two-photon stimulated Raman pulse generator is used for applying two descending cold atomic groups with two vertically upward two-photon stimulated Raman pulses again, and superposing and combining internal states of the two cold atomic groups to enable the two cold atomic groups to generate interference;
the second Raman beam laser applies two-photon stimulated Raman pulses vertically downwards to the two cold atomic groups entering the free falling body area, inverts the internal states of the two cold atomic groups and transfers the amount of movement;
the optical lattice component traps two cold atomic groups with inverted states, and limits the spatial displacement and diffusion of the two cold atomic groups until the two cold atomic groups fall freely;
and the signal collector is used for collecting interference fringes of the interfered cold atomic groups.
2. The cold atom gravimeter of claim 1 wherein the ground state cold atom preparation machine comprises:
a cold atom preparing device for preparing high-energy-state cold atomic groups with a vertical upward speed;
and the state selection cavity is used for providing a microwave oscillating field for the high-energy-state cold atomic group and preparing the high-energy-state cold atomic group into a ground-state cold atomic group.
3. The cold atom gravimeter of claim 2 wherein the cold atom preparation device comprises:
an atom source providing atoms;
the magneto-optical trap cooling assembly is used for cooling atoms to complete the preparation of cold atomic groups;
and the laser is used for projecting the cold atomic groups in the vertical direction, providing the moving speed in the vertical direction for the static cold atomic groups and converting the static cold atomic groups into high-energy-state cold atomic groups.
4. The cold atom gravimeter of claim 3 wherein the second Raman beam laser, the optical lattice assembly, the phase selection chamber, the magneto-optical trap cooling assembly, the first Raman beam laser, and the laser are sequentially positioned from top to bottom along an axial centerline of the vacuum chamber.
5. The cold atom gravimeter of claim 4 wherein the signal collector is disposed between the magneto-optical trap cooling assembly and the phase selection chamber on one side of the axial centerline.
6. A cold atom gravimeter according to claim 3, wherein the magneto-optical trap cooling assembly comprises an anti-helmholtz coil and 6 lasers, the centerline of the vacuum chamber passing through the center of the anti-helmholtz coil, the 6 lasers being uniformly distributed around the circumference of the anti-helmholtz coil.
7. The cold atom gravimeter of claim 1, wherein the optical frequency difference of the raman laser beams emitted by the first and second raman beam lasers is equal to an atomic ground state level splitting spacing.
8. A method for detecting a cold atom gravimeter, in which the cold atom gravimeter according to any one of claims 1 to 7 is used, and the method comprises:
preparing ground state cold radicals moving vertically upwards;
applying a first vertical upward two-photon stimulated Raman pi/2 pulse to the ground state cold radicals, dividing the ground state cold radicals into two cold radicals in a superposed state and at different speeds, and splitting the two cold radicals into two paths to move;
applying two-photon stimulated Raman pi pulses to the two cold radicals entering the free falling body area, inverting the internal states of the two cold radicals, and transferring the momentum of the two cold radicals;
trapping the two cold atomic groups with reversed internal states, and limiting the spatial displacement and diffusion of the two cold atomic groups until the two cold atomic groups fall freely;
applying two-photon stimulated Raman pi/2 pulses which are vertically upward again to the two descending cold radicals, and superposing and combining the internal states of the two cold radicals to enable the two cold radicals to generate interference;
interference fringes of the cold radicals subjected to interference are collected.
9. The method for detecting the cold atom gravimeter according to claim 8, wherein the preparing of the ground-state cold atom group moving vertically upward specifically includes:
preparing high-energy state cold atomic groups with vertical upward speed;
and providing a microwave oscillating field for the high-energy state cold atomic groups, and preparing the high-energy state cold atomic groups into ground state cold atomic groups.
10. The method for detecting the cold atom gravimeter according to claim 9, wherein the preparing of the high-energy cold atom group with a vertical upward velocity includes:
cooling the provided atoms to finish the preparation of cold atomic groups;
and (3) projecting the cold atomic groups in the vertical direction, providing a moving speed in the vertical direction for the static cold atomic groups, and converting the static cold atomic groups into high-energy-state cold atomic groups.
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| CN114137626B (en) * | 2021-11-30 | 2023-11-21 | 中国人民解放军国防科技大学 | Method for determining equivalent height of atomic gravimeter by modulating Raman laser |
| CN114689282B (en) * | 2022-03-15 | 2022-12-20 | 华中科技大学 | Atomic interference device and method for calibrating amplification factor of imaging system on line |
| CN116466273B (en) * | 2023-06-20 | 2023-08-29 | 广东威纳格科技有限公司 | Atomic interferometer for synchronously measuring gravitational acceleration and magnetic field and method thereof |
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| FR2988863B1 (en) * | 2012-03-28 | 2014-11-21 | Onera (Off Nat Aerospatiale) | DIFFERENTIAL INERTIAL MEASURING APPARATUS |
| US9134450B2 (en) * | 2013-01-07 | 2015-09-15 | Muquans | Cold atom gravity gradiometer |
| CN103337271B (en) * | 2013-06-21 | 2015-09-02 | 江苏大学 | A kind of Trapping of Atoms of chip surface and Optical Lattices method |
| CN103837904B (en) * | 2014-03-20 | 2016-04-20 | 中国科学院武汉物理与数学研究所 | Based on combination inertial sensor and the measuring method thereof of many constituent atoms interferometer |
| CN104007480B (en) * | 2014-06-12 | 2016-08-17 | 中国科学院武汉物理与数学研究所 | Horizontal gravity gradient based on cold atomic beam interferometer measures sensor |
| CN203881958U (en) * | 2014-06-12 | 2014-10-15 | 中国科学院武汉物理与数学研究所 | Level gravity gradient measurement sensor based on cold atomic beam interferometer |
| CN107525946A (en) * | 2017-08-25 | 2017-12-29 | 中国人民解放军国防科技大学 | Acceleration measurement method and device based on atomic interference in optical waveguide |
| CN110850497B (en) * | 2019-11-21 | 2022-06-10 | 中国船舶重工集团公司第七0七研究所 | Absolute gravimeter, gyroscope sensor and method based on atomic interference effect |
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