Method and apparatus for measuring probe tilt for single component atomic shear interferometer

Abstract

The application discloses a method for measuring a detection tilt angle of a single-component atomic shearing interferometer, a method for measuring a detection tilt angle of a single-component atomic shearing interferometer, and a tilt angle set of a pendulum angle device is constructed; a rotation angle of a mirror is detected between the time when an atom is subjected to the action of a pi Raman laser and the time when the atom is subjected to the action of a second pi / 2 Raman laser; a shearing interference fringe image is detected; all tilt angles in the tilt angle set are traversed; and an actual included angle of a longitudinal direction of a CCD camera imaging plane relative to a Z-axis direction is calculated by fitting. The application further discloses a measuring device for a detection tilt angle of a single-component atomic shearing interferometer. The application enables the current atomic shearing interferometer to realize accurate measurement of a tilt angle of a detection system thereof, thereby solving the problems of noise and system error caused by the non-zero return of the tilt angle of the detection system of the atomic shearing interferometer, and suppressing the drift of the single-component atomic interferometer caused by the change of the tilt angle.

Description

Technical Field

[0001] This invention belongs to the field of precision measurement physics. Specifically, it relates to a method for measuring the probe tilt angle of a single-component atomic shearing interferometer, and also to a device for measuring the probe tilt angle of a single-component atomic shearing interferometer. Background Technology

[0002] In recent years, the development of laser-manipulated atomic technology has greatly promoted the application of atomic interferometers in fundamental physics research and inertial measurement. Especially in gravity measurement, atomic interferometers have become one of the most mature and widely used tools. Since the first measurement of gravitational acceleration using an atomic interferometer in 1992, various related technologies have flourished, among which the shear phase shift readout method is particularly prominent. The shear phase shift readout method pioneered by A. Sugarbaker et al. (Phys. Rev. Lett. 111, 113002, 2013) significantly reduces the influence of atomic number fluctuations and contrast changes on the phase by detecting high-resolution spatial interference fringes, laying the technical foundation for real-time high-precision measurement. This technology has subsequently found expanded applications in multiple dimensions: P. Asenbaum et al. (Phys.Rev.Lett.123,191101,2020) applied it to long-baseline gravity-rotation synchronous measurements, D. Yankelev et al. (Sci.Adv.6,eabd0650,2020) combined the Mohr effect to extend the dynamic range of gravity by three orders of magnitude, while GWHoth (Appl.Phys.Lett.109,071113,2016) and YJChen et al. (Phys.Rev.Appl.12,014019,2019) developed rotation measurement and multi-axis gyroscope schemes, respectively.

[0003] Compared to traditional interferometry, atomic shearing interferometry can acquire complete phase and contrast information of an atomic interferometer in a single measurement, demonstrating significant advantages under long free evolution times. As the evolution time increases, noise accumulation leads to a sharp decline in the system's signal-to-noise ratio and fringe contrast. Traditional methods struggle to extract phase information when contrast is low, while shearing interferometry can still maintain effective measurements.

[0004] However, in atomic interferometers employing shear phase readout technology, the phase of the interference fringes is directly related to the spatial position. Changes in relative position or angle will introduce noise and systematic errors. In previous research, Yan et al. (Phys.Rev.A 108,063313,2023) effectively suppressed noise and systematic errors caused by relative position changes by using an alternating measurement method of positive and negative tilt angles of the Raman laser wave vector. Another important source of this type of error is the tilt angle of the vertical direction of the atomic shear interferometer's detection system (i.e., the longitudinal direction of the CCD camera's imaging plane) relative to the direction of gravity, hereinafter referred to as the detection system tilt angle. When the detection system tilt angle is not zero, it introduces a height-dependent phase shift; changes in the tilt angle and fluctuations in atomic positions also lead to changes in phase noise. Atomic interferometers generally require long-term measurements, and applied atomic interferometers need to operate in environments with significant vibration noise and temperature fluctuations. Therefore, accurate measurement of the detection system tilt angle is crucial for achieving high-precision measurements with atomic shear interferometers and will enhance its application potential in gravity measurement, rotation measurement, and equivalent principle verification research. Summary of the Invention

[0005] This invention addresses the aforementioned problems in the existing technology by proposing a method for measuring the probe tilt angle of a single-component atomic shearing interferometer, and also proposes a device for measuring the probe tilt angle of a single-component atomic shearing interferometer, thereby enabling effective measurement of the angle between the longitudinal direction of the CCD camera imaging plane and the direction of gravity.

[0006] The above-mentioned objectives of the present invention are achieved through the following technical means:

[0007] A measuring device for the probe tilt angle of a single-component atomic shearing interferometer includes a vacuum system comprising, from bottom to top, a cooling confinement zone, a probe zone, and an interference zone.

[0008] The cooling prison is initially set up with a single-component cold atom cluster, which is... 87 Rb cold atom group,

[0009] A horizontally cooled laser is incident on the cooled confinement area. A detection system is set outside the detection area, including a tilting device and a CCD camera mounted on the tilting device. A reflector is set below the cooled confinement area and is mounted on a deflection system.

[0010] The longitudinal cooling laser A, the detector laser A, the first π / 2 Raman laser A, the π Raman laser A, and the second π / 2 Raman laser A are all vertically downwards and sequentially incident from the top of the interference region into the interference region, the detector region, and the cooling confinement area.

[0011] The longitudinal cooling laser B, the detection laser B, the first π / 2 Raman laser B, the π Raman laser B, and the second π / 2 Raman laser B are reflected by a mirror and then sequentially enter the cooling trap zone, the detection zone, and the interference zone.

[0012] The horizontal direction of the CCD camera's imaging surface is parallel to the Y' axis of the imaging two-dimensional coordinate system, the vertical direction of the CCD camera's imaging surface is parallel to the Z' axis of the imaging two-dimensional coordinate system, the X and Y axes of the three-dimensional coordinate system are located on the horizontal plane and are perpendicular to each other, the Z axis of the three-dimensional coordinate system is perpendicular to the horizontal plane, and the horizontal rotation axis of the reflector is parallel to the Y axis of the three-dimensional coordinate system.

[0013] The interference region is located within the magnetic shielding system.

[0014] A method for measuring the probe tilt angle of a single-component atomic shearing interferometer, utilizing the aforementioned measuring device for the probe tilt angle of a single-component atomic shearing interferometer, includes the following steps:

[0015] Step 1: Construct the tilt angle set of the oscillator;

[0016] Step 2: The single-component cold atomic clusters are cooled and trapped in the cooling confinement zone by longitudinal cooling laser A, cooling laser B, and two pairs of horizontal cooling lasers, and then thrown upwards;

[0017] Step 3: After the single-component cold atom cluster enters the interference region within the magnetic shielding system, a Mach-Zehnder atomic shearing interferometer is realized through a first π / 2 Raman laser-π Raman laser-second π / 2 Raman laser. The first π / 2 Raman laser includes first π / 2 Raman laser A and first π / 2 Raman laser B, the π Raman laser includes π Raman laser A and π Raman laser B, and the second π / 2 Raman laser includes second π / 2 Raman laser A and second π / 2 Raman laser B. Between the moment the atom is subjected to the π Raman laser and the second π / 2 Raman laser, the reflector 108 rotates by an angle θ under the action of the deflection system.

[0018] Step 4: The single-component cold atomic clusters fall freely into the detection area, and a detection laser is applied to detect the atomic shearing interference fringe image. After the detection is completed, steps 2 and 3 are repeated and the detection is repeated multiple times to obtain multiple atomic shearing interference fringe images at an inclination angle of α.

[0019] Step 5: Calculate the phase difference between the ground state upper energy level and the ground state lower energy level atomic shearing interferometer in each atomic shearing interferometer pattern at tilt angle α. Take the average value of all atomic shearing interferometer phase differences to form multiple sets of average phase differences between the ground state upper energy level and the ground state lower energy level at tilt angle α.

[0020] Rotate the pendulum to the next measured tilt angle α and return to step 2 until all tilt angles in the tilt angle set have been traversed, then proceed to step 6;

[0021] Step 6: Perform linear fitting on the average phase difference between the atomic shearing interferometer of the ground state upper energy level and the ground state lower energy level for all groups with tilt angle α to obtain the first fitting line, and plot it. The line represented is used to obtain the first fitted line and... The intersection of the lines represented by the line, and the tilt angle α0 corresponding to the x-coordinate of the intersection point, is the actual angle between the longitudinal direction of the CCD camera imaging surface and the Z-axis direction when the tilt angle of the tilt device is set to 0.

[0022] The inclination angles in the set of inclination angles are distributed arithmetically with 0 as the center.

[0023] In step 3 87 At time t1, the atoms of the Rb group are subjected to the first π / 2 Raman laser, which splits the atom beam into two paths. After time T, at time t2, they are subjected to the π Raman laser, which reverses the two paths of the atom. After another time T, at time t3, they are subjected to the second π / 2 Raman laser, which makes the two paths of the atom coincide, thus achieving atomic interference.

[0024] In step 4, the detection of the atomic shearing interference fringe image includes the following steps: applying a back-pump laser before applying the detection laser.

[0025] The phase difference between the ground state upper energy level and the ground state lower energy level atomic shearing interferometer of each atomic shearing interference fringe image is obtained based on the following steps:

[0026] Interference fringes at the ground state upper and lower energy levels are selected from the same atomic shearing interference fringe image. Gaussian multiplication and sine fitting are performed on the two sets of interference fringes respectively to extract the phase information of the interference fringes at the ground state upper and lower energy levels. The difference between the phase information of the interference fringes at the ground state upper and lower energy levels is calculated as the atomic shearing interferometer phase difference of the atomic shearing interference fringe image. The atomic shearing interferometer phase difference of each atomic shearing interference fringe image is calculated.

[0027] The present invention has the following advantages over the prior art:

[0028] Before the last Raman pulse in a traditional π / 2-π-π / 2 three-pulse Mach-Zehnder atomic interferometer, the mirror is adjusted so that the Raman laser wave vector direction has an additional angle with the atomic velocity direction (the directions of the wave vectors of the first two Raman pulses remain unchanged and are parallel to the atomic velocity direction). Through this process, a horizontal shear phase shift can be introduced within the spatial distribution range of atomic clusters, thereby spatially modulating the phase of atomic matter waves. Further, an imaging detection system can be used to obtain the spatial phase distribution of the atomic interferometer. The above part is the same as that of a traditional atomic shear interferometer. The method of this patent for measuring the tilt angle of the atomic shear interferometer detection system is as follows: Each measurement uses a different detection system tilt angle, and the shear interference fringe images of the upper and lower energy levels are detected simultaneously. The phase difference between the interference fringes of the upper and lower ground state energy levels, separated by a certain distance in the longitudinal direction of the CCD camera imaging plane, can be obtained. This phase difference changes linearly with the tilt angle of the detection system. By comparing this phase difference with π (the theoretical value of the shear interference phase difference between the upper and lower energy levels in a single-component atomic interferometer), the actual tilt angle of the detection system can be determined.

[0029] This enables current atomic shearing interferometers to accurately measure the tilt angle of their detection system, thereby solving the noise and system error problems caused by the non-zero tilt angle of the atomic shearing interferometer's detection system, and laying the foundation for the high-precision application of single-component atomic shearing interferometers. Attached Figure Description

[0030] Figure 1 A schematic diagram of the atomic shearing interferometer device in an embodiment of the present invention;

[0031] Figure 2 Schematic diagram of stimulated Raman transition in an embodiment of the present invention;

[0032] Figure 3 A schematic diagram of the atomic shearing interferometer in this embodiment of the invention;

[0033] Figure 4 A schematic diagram of the tilt angle of the detection system in this embodiment of the invention;

[0034] Figure 5 A schematic diagram of the debugging method in an embodiment of the present invention.

[0035] In the diagram, 101: Single-component cold atomic cluster; 102: Vacuum system; 103: Magnetic shielding system; 104: Cooling light component (horizontally cooled laser); 105: Cooling light component (vertical cooled laser, probe laser); 106: Raman light component (π Raman laser, π / 2 Raman laser); 107: Deflection system; 108: Mirror; 109: Detection system CCD camera; 110: Swing; 111: Sheared interference fringes; 1021: Cooled confinement zone; 1022: Detection zone; 1023: Interference zone.

[0036] |201>: Lower ground state, |202>: Upper ground state, |203>: Virtual energy level, |204>: Excited state, CCDplane - CCD camera imaging surface. Detailed Implementation

[0037] To facilitate understanding and implementation of the present invention by those skilled in the art, the present invention will be further described in detail below with reference to embodiments. It should be understood that the embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0038] Example 1:

[0039] A measuring device for the probe tilt angle of a single-component atomic shearing interferometer, in an embodiment, such as... Figure 1 As shown, it includes a single-molecule cold atom group 101 (in this embodiment, it is...). 87 The system includes: Rb cold atom clusters, vacuum system 102, magnetic shielding system 103, horizontally cooled laser 104, longitudinal laser group (in this embodiment, it includes a longitudinally cooled laser and a probe laser; the longitudinally cooled laser includes longitudinally cooled laser A and longitudinally cooled laser B; the probe laser includes probe laser A and probe laser B) 105, pump-back laser, Raman laser group (in this embodiment, it includes a first π / 2 Raman laser, a π Raman laser, and a second π / 2 Raman laser; the first π / 2 Raman laser includes first π / 2 Raman laser A and first π / 2 Raman laser B; the π Raman laser includes π Raman laser A and π Raman laser B; the second π / 2 Raman laser includes second π / 2 Raman laser A and second π / 2 Raman laser B) 106, deflection system 107, reflector 108, CCD camera 109, and tilting device 110.

[0040] The lasers involved in this invention are classified into two categories according to their applications. The first category is the cooling light part, which includes cooling lasers (two pairs of horizontal cooling lasers 104 and one pair of vertical cooling lasers). The second category is the Raman light part, which includes a first π / 2 Raman laser, a π Raman laser, and a second π / 2 Raman laser. The third category is the probe laser and the pump-back laser.

[0041] The vacuum system 102 includes a cooling confinement zone 1021, a detection zone 1022, and an interference zone 1023 arranged from bottom to top. The interference zone 1023 is located within the magnetic shielding system 103.

[0042] The initial position of the cold atom cluster is located in the cooling cage exclusion zone 1021. Two pairs of mutually perpendicular horizontal cooling lasers 104 are arranged outside the cooling cage exclusion zone 1021. A detection system (including a tilting device 110 and a CCD camera 109 mounted on the tilting device 110) is arranged outside the detection zone 1022. The longitudinal cooling laser A, detection laser A, first π / 2 Raman laser A, π Raman laser A and second π / 2 Raman laser A are all vertically downward and sequentially incident on the interference zone 1023, the detection zone 1022 and the cooling cage exclusion zone 1021 from the top of the interference zone 1023. The cooling cage exclusion zone 1021 is located in the region of... Below the system, a reflector 108 is positioned at an initial angle of 45 degrees to the horizontal plane. At this initial angle, the longitudinal cooling laser B, the detection laser B, the first π / 2 Raman laser B, the π Raman laser B, and the second π / 2 Raman laser B are reflected vertically upwards by the reflector 108 and sequentially enter the cooling confinement zone 1021, the detection zone 1022, and the interference zone 1023. The reflector 108 is mounted on the deflection stage (PZT) of the deflection system 107. The PZT controls the tilt angle of the reflector 108, thereby changing the direction of the reflected second π / 2 Raman laser B. The detection system includes a lens, a CCD camera 109, and a tilting device 110. The CCD camera 109 is mounted on the tilting device 110, and the lens is located in front of the CCD camera. The imaging plane of the CCD camera is perpendicular to the horizontal plane.

[0043] The X and Y axes of the three-dimensional coordinate system XYZ are defined to be located on the horizontal plane and perpendicular to each other. The Z axis of the three-dimensional coordinate system XYZ is perpendicular to the horizontal plane. The Y' axis of the imaging two-dimensional coordinate system is defined to be parallel to the horizontal direction of the CCD camera imaging surface. The Z' axis of the imaging two-dimensional coordinate system is parallel to the vertical direction of the CCD camera imaging surface. The Y' axis of the imaging two-dimensional coordinate system is perpendicular to the Z' axis. The horizontal rotation axis of the reflector 108 is parallel to the Y axis of the three-dimensional coordinate system. In this embodiment, the CCD camera imaging surface is parallel to the Y-axis-Z-axis plane.

[0044] Adjusting the tilt angle of the tilting device 110 changes the angle between the longitudinal direction of the CCD camera's imaging surface and the Z-axis direction.

[0045] Example 2:

[0046] A method for measuring the probe tilt angle of a single-component atomic shearing interferometer, utilizing the measuring device for measuring the probe tilt angle of a single-component atomic shearing interferometer described in Example 1, includes the following steps:

[0047] Step 1: Construct the tilt angle set {α1, α2, α3, ..., α} of the tilt angle device 110. nThe tilt angles in the tilt angle set are distributed arithmetically around 0 (e.g., -34.8 mrad, -26.1 mrad, -17.4 mrad, -8.7 mrad, 0, +8.7 mrad, +17.4 mrad, +26.1 mrad, +34.8 mrad, where the arithmetic mean is 0 and the common difference is 8.7 mrad). n is the number of tilt angles α and is odd. A tilt angle α is selected from the tilt angle set, and the rotation of the CCD camera 109 at the selected tilt angle α is achieved by the oscillator 110.

[0048] Step 2: Implementation of a single-component atomic fountain. 87 Rb cold atom clusters are cooled and trapped in a cooling confinement zone 1021 by longitudinal cooling laser A, longitudinal cooling laser B, and two pairs of horizontal cooling lasers 104, by changing the relative frequencies of longitudinal cooling laser A and longitudinal cooling laser B. 87 Rb cold atom clusters are thrown upwards with initial velocity, forming an atomic fountain. 87 During the upward throw of Rb atoms, they enter the interference region 1023 located within the magnetic shielding system 103. At this time... 87 The Rb atom is in the upper ground state |202>. The energy level structure of the atom is as follows: Figure 2 As shown.

[0049] Step 3: Implementation of the atomic shearing interferometer. 87 After the Rb cold atom cluster enters the interference region 1023 within the magnetically shielded system, a Mach-Zehnder atomic shearing interferometer is realized through a first π / 2 Raman laser-π Raman laser-second π / 2 Raman laser. At time t1, the atom is acted upon by the first π / 2 Raman laser, splitting the atom into two paths; after time T, at time t2, it is acted upon by the π Raman laser, causing the two paths to reverse; after another time T, at time t3, it is acted upon by the second π / 2 Raman laser, causing the two paths to coincide, thus achieving atomic interference. The first π / 2 Raman laser-π Raman laser-second π / 2 Raman laser sequence enables two-photon Raman transitions between the lower and upper ground states of the atom. Between the time the atom is acted upon by the π Raman laser and the second π / 2 Raman laser, the reflector 108 at the bottom of the vacuum system 102 rotates by an angle θ under the action of the deflection system 107, thereby introducing a shearing phase into the atom in the horizontal direction. The principle is as follows: Figure 3 As shown.

[0050] Among them, π / 2 Raman pulses and π Raman pulses can be used to achieve 87 Two-photon stimulated Raman transition of Rb atoms between the lower ground state |201> and the upper ground state |202>.

[0051] Step 4: Multiple single-component atomic signal detections. After interference is achieved via a first π / 2 Raman laser, a second π / 2 Raman laser, and a third π / 2 Raman laser... 87 Rb atoms fall freely into detector region 1022. First, a pump-back laser is applied (this replenishes the number of atoms in the ground-state energy level; when the detector laser is applied, the interference fringes of the ground-state energy level are detected). Then, a... 87 The detection laser for Rb atomic resonance, under the action of the detection laser 105, detects the atomic shearing interference fringe images (including interference fringes at the upper and lower ground state energy levels) by the CCD camera 110 of the detection system. After detection, steps 2 and 3 are repeated for re-detection, and this process is repeated multiple times to obtain multiple atomic shearing interference fringe images at an inclination angle of α.

[0052] Step 5: Data Processing. Select the atomic shearing interference fringe image obtained in Step 4. Select the ground-state upper-level interference fringes and the ground-state lower-level interference fringes from the atomic shearing interference fringe image. The phase difference between the ground-state upper-level interference fringes and the ground-state lower-level interference fringes is the atomic shearing interferometer phase difference. Perform Gaussian multiplication sine fitting on the ground-state upper-level interference fringes and the ground-state lower-level interference fringes of the same atomic shearing interference fringe image to extract the phase information of the ground-state upper-level interference fringes and the ground-state lower-level interference fringes on the atomic shearing interference fringe image, and calculate the atomic shearing interferometer phase difference of the atomic shearing interference fringe image. Calculate the atomic shearing interferometer phase difference for each atomic shearing interference fringe image, and take the average of all atomic shearing interferometer phase differences to obtain the average atomic shearing interferometer phase difference between the ground-state upper-level interference fringes and the ground-state lower-level interference fringes when the tilt angle is α. From this, we can obtain an ordered pair.

[0053] Then rotate the pendulum 110 to the next measured tilt angle α, and return to step 2, until all tilt angles in the tilt angle set have been traversed, resulting in multiple sets of pairs.

[0054] Step 6: Obtain multiple pairs of numbers for different values ​​of the inclination angle α. Painted in the same In the coordinate graph, perform a linear fit; and simultaneously plot... The straight line is represented by the following. According to the basic principles of quantum mechanics and atomic interferometers, the phase difference between the shear interference phases of the upper and lower energy levels in a single-component atomic interferometer is always π (that is, the phase difference between these two sets of atomic interference fringes in space is definite and independent of the distance between them). Therefore, the intersection point of the two straight lines is obtained, and the value α0 corresponding to the x-coordinate of the intersection point is the actual angle between the longitudinal direction of the CCD camera imaging plane and the Z-axis direction when the tilt angle of the oscillator 110 is set to 0.

[0055] A brief explanation of the principle behind shear phase shift:

[0056] The interaction between the second π / 2 Raman laser and atoms in the single-component cold atom cluster 101 (i.e. Figure 3 Before time t3, under the action of the deflection system 107, the reflector 108 causes the wave vector of the second π / 2 Raman laser to be deflected at an angle of 2θ from the velocity direction of the atoms in the single-component cold atom cluster 101. Then, after the interaction of the first π / 2 Raman laser - π Raman laser - second π / 2 Raman laser ends, at time t... d Imaging and detection of the single-component cold atom cluster 101 at all times reveals that the probability of atoms being in a specific internal state varies at different spatial locations (i.e., the phase of the atomic interference fringes is different at different horizontal positions).

[0057] When the tilt angle of the pendulum 110 of the detection system is not zero, such as Figure 4 As shown, assuming the angle between the projection direction Z(g) of the gravity direction (Z-axis direction) onto the CCD camera imaging plane (also parallel to the Z-axis direction) and the longitudinal direction (z′ direction) of the CCD camera imaging plane is b, b = a0 + a, where a0 is the actual angle between the longitudinal direction of the CCD camera imaging plane and the Z-axis direction when the tilt angle of the tilting device 110 is set to 0, and a is the tilt angle of the tilting device 110, then the intensity distribution and phase expression n(x) of the interference pattern obtained by imaging can be calculated by combining the probability that the atoms are in a specific internal state after interference. t3 ,t3) is:

[0058]

[0059] Where N is the total number of atoms in a single-component cold atomic group, σ x The Gaussian half-width of the single-component cold atom group 101 at time t3 is x. t3 and z t3 The X and Z axes represent the positions of the center of the single-component atomic cluster 101 at time t3 in the three-dimensional coordinate system, respectively. C0 represents the contrast of the single-component atomic shearing interferometer, and the spatial frequency of the shearing fringe is... k eff Let x be the effective wave vector of the Raman laser, θ be the deflection angle of the mirror 108 under the action of the deflection system 107, and x be the effective wave vector of the Raman laser. m Let X be the position of the horizontal rotation axis of mirror 108 on the X-axis. The phase shift introduced by gravitational acceleration.

[0060] Methods for measuring the tilt angle of a detection system:

[0061] In a single-component atomic shearing interferometer, after Gaussian fitting of the interference fringes at the upper and lower ground state levels, the Gaussian center positions of these fringes are extracted. The distance Δz′ between these Gaussian center positions along the longitudinal direction of the CCD camera imaging plane is obtained, along with the phase difference Φ between the upper and lower ground state interference fringes. diff for:

[0062] Φ diff =κ d bΔz′+φ′0

[0063] Among them, κ d Let φ be the spatial frequency of the shear fringes, b be the angle between the projection direction of gravity onto the CCD camera imaging plane and the longitudinal direction of the CCD camera imaging plane, and Δz′ be the distance along the longitudinal direction of the CCD camera imaging plane between the Gaussian centers of the ground-state upper and lower energy level interference fringes. φ′0 is the initial differential phase shift.

[0064] Analysis of the above equation reveals that when the distance Δz′ is fixed, changing the tilt angle α of the pendulum 110 introduces different phase differences, and there is a linear relationship between the two. Therefore, the tilt angle α can be adjusted by changing the angle of the pendulum 110, and the average phase difference between the tilt angle α and the atomic shearing interferometer of the ground state upper and lower energy levels obtained under different values ​​of tilt angle α can be calculated. The first fitted line was obtained by fitting the lines, and then... The second fitted line is obtained. The two fitted lines intersect near the position where the tilt angle is zero. That is, the x-coordinate of the intersection point of the first and second fitted lines obtained by linear fitting corresponds to the angle between the longitudinal direction of the CCD camera imaging plane and the Z-axis direction when the tilt angle of the oscillator 110 is set to 0 (e.g., Figure 5 (The location of the intersection of the relationship curves obtained from the experiment).

[0065] It should be noted that the specific embodiments described in this invention are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention pertains can make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of the invention or exceeding the scope defined by the appended claims.

Claims

1. A method for measuring the probe tilt angle of a single-component atomic shearing interferometer, utilizing a measuring device for the probe tilt angle of a single-component atomic shearing interferometer, the measuring device comprising a vacuum system (102), said vacuum system (102) comprising, from bottom to top, a cooling confinement zone (1021), a probe zone (1022), and an interference zone (1023), the interference zone (1023) being located within a magnetic shielding system (103), The cooling prison (1021) is initially set with a single-component cold atom cluster (101), which is a single-component cold atom cluster (101) for... 87 Rb cold atom group, Two pairs of mutually perpendicular horizontal cooling lasers (104) are incident on the cooling confinement area (1021). A detection system is set outside the detection area (1022). The detection system includes a tilting device (110) and a CCD camera (109) set on the tilting device (110). The imaging surface of the CCD camera is perpendicular to the horizontal plane. A reflector (108) is set below the cooling confinement area. The reflector (108) is set on the deflection system (107). The longitudinal cooling laser A, the detection laser A, the first π / 2 Raman laser A, the π Raman laser A, and the second π / 2 Raman laser A are all vertically downward and sequentially incident from the top of the interference region into the interference region (1023), the detection region (1022), and the cooling confinement area (1021). The longitudinal cooling laser B, the detection laser B, the first π / 2 Raman laser B, the π Raman laser B, and the second π / 2 Raman laser B are reflected by the mirror and then sequentially enter the cooling trap area (1021), the detection area (1022), and the interference area (1023). The CCD camera's imaging surface has a horizontal direction parallel to the Y' axis of the two-dimensional imaging coordinate system, a vertical direction parallel to the Z' axis of the two-dimensional imaging coordinate system, and the X and Y axes of the three-dimensional coordinate system are located on the horizontal plane and perpendicular to each other. The Z axis of the three-dimensional coordinate system is perpendicular to the horizontal plane. The horizontal rotation axis of the reflector (108) is parallel to the Y axis of the three-dimensional coordinate system. The tilt angle of the tilting device (110) is adjusted to change the angle between the vertical direction of the CCD camera's imaging surface and the Z-axis direction. The CCD camera's imaging surface has a horizontal direction parallel to the Y' axis of the two-dimensional imaging coordinate system, and the vertical direction is parallel to the Z-axis direction. The measurement method includes the following steps: Step 1: Construct a set of tilt angles for the tilting device (110), select a tilt angle α from the tilt angle set, and rotate the CCD camera (109) by the tilting device (110) at the selected tilt angle α; Step 2: The single-component cold atom cluster (101) is cooled and trapped in the cooling confinement zone (1021) by longitudinal cooling laser A, longitudinal cooling laser B and two pairs of mutually perpendicular horizontal cooling lasers (104), and then thrown upward into the interference zone (1023) located in the magnetic shielding system (103). Step 3: After the single-component cold atomic cluster (101) enters the interference region (1023) within the magnetic shielding system (103), a Mach-Zehnder atomic shearing interferometer is realized through a first π / 2 Raman laser-π Raman laser-second π / 2 Raman laser. The first π / 2 Raman laser includes a first π / 2 Raman laser A and a first π / 2 Raman laser B; the π Raman laser includes π Raman laser A and π Raman laser B; and the second π / 2 Raman laser includes a second π / 2 Raman laser A and a second π / 2 Raman laser B. In Raman laser B, the atom is acted upon by the first π / 2 Raman laser at time t1, splitting the atom into two paths. After time T, at time t2, it is acted upon by the π Raman laser, causing the two paths to reverse. After another time T, at time t3, it is acted upon by the second π / 2 Raman laser, causing the two paths to overlap, thus achieving atomic interference. Between the time the atom is acted upon by the π Raman laser and the second π / 2 Raman laser, the mirror (108) rotates by an angle under the action of the deflection system. ; Step 4: After interference, the single-component cold atom cluster (101) falls freely into the detection area (1022). A detection laser that resonates with the single-component cold atom cluster (101) is applied to detect the atomic shearing interference fringe image. After detection, Step 2 and Step 3 are repeated and the detection is repeated multiple times to obtain multiple atomic shearing interference fringe images at an inclination angle of α. Step 5: Calculate the phase difference between the ground state upper energy level and the ground state lower energy level atomic shearing interferometer in each atomic shearing interferometer pattern at tilt angle α. Take the average value of all atomic shearing interferometer phase differences to form the average phase difference between the tilt angle α and the ground state upper energy level atomic shearing interferometer. , Rotate the pendulum (110) to the next measured tilt angle α and return to step 2 until all tilt angles in the tilt angle set have been traversed, then proceed to step 6; Step 6: Average the phase difference between the atomic shearing interferometers of all groups of tilt angle α-ground state upper and lower energy levels. Perform linear fitting to obtain the first fitted line, and plot it. The line represented is used to obtain the first fitted line and... The intersection of the lines represented by the line, and the tilt angle α0 corresponding to the x-coordinate of the intersection point, is the actual angle between the longitudinal direction of the CCD camera imaging surface and the Z-axis direction when the tilt angle of the tilt device (110) is set to 0.

2. The method for measuring the probe tilt angle of a single-component atomic shearing interferometer according to claim 1, characterized in that, The inclination angles in the set of inclination angles are distributed arithmetically with 0 as the center.

3. The method for measuring the probe tilt angle of a single-component atomic shearing interferometer according to claim 1, characterized in that, In step 4, the detection of the atomic shearing interference fringe image includes the following steps: applying a back-pump laser before applying the detection laser.

4. The method for measuring the probe tilt angle of a single-component atomic shearing interferometer according to claim 2, characterized in that, The phase difference between the ground state upper energy level and the ground state lower energy level atomic shearing interferometer of each atomic shearing interference fringe image is obtained based on the following steps: Interference fringes at the ground state upper and lower energy levels are selected from the same atomic shearing interference fringe image. Gaussian multiplication and sine fitting are performed on the two sets of interference fringes respectively to extract the phase information of the interference fringes at the ground state upper and lower energy levels. The difference between the phase information of the interference fringes at the ground state upper and lower energy levels is calculated as the atomic shearing interferometer phase difference of the atomic shearing interference fringe image. The atomic shearing interferometer phase difference of each atomic shearing interference fringe image is calculated.

Images