Single-Source Multiaxis Cold-Atom Interferometer in a Centimeter-Scale Cell

Abstract

Using the technique of point source atom interferometry (PSI), we characterize the sensitivity of a multi-axis gyroscope based on free-space Raman interrogation of a single source of cold atoms in a glass vacuum cell. The instrument simultaneously measures the acceleration in the direction of the Raman laser beams and the projection of the rotation vector onto the plane perpendicular to that direction. The sensitivities for the magnitude and direction of the rotation vector measurement are 0.033 • /s and 0.27 • with one second averaging time, respectively. The fractional acceleration sensitivity δg/g is 1.6 × 10 −5 / √ Hz. The sensitivity could be improved by increasing the Raman interrogation time, allowing the cold-atom cloud to expand further, correcting the fluctuations in the initial cloud shape, and reducing sources of technical noise. The PSI technique resolves a rotation vector in a plane by measuring a phase gradient. This two-dimensional rotation sensitivity may be specifically important for applications such as tracking the precession of a rotation vector and gyrocompassing.

Robust inertial sensing with point-source atom interferometry for interferograms spanning a partial period

“…We first perform principal component analysis (PCA) to the set of four images to remove some background noise, and then apply a 2D curve fit to the four cleaned fringe images with the plane wave function in Equation 5. We refer to this approach as the "PCA method," which has been used in previous PSI works [9,10,23]. PCA is model-free, and has been used in different atomic systems to remove noise in the images before analyzing the data with a physical model [25,26].…”

“…The experimental setup has been described in our previous work [23]; however, in the present work, we use a different experimental timing sequence to acquire the four fringe images for demonstrating the SHEEP method (without changing the hardware).…”

“…The simplification from sinusoidal fitting with five parameters (fringe analysis) to linear fitting with three parameters (phase map analysis) contributes to the robustness of the SHEEP method. However, since the same image data is used in each method, the effects of quantum projection noise should be the same for both methods and their effects on the Allan deviation are calculated and shown in [23].…”

“…Our experimental setup is built on a floating optical table without active vibration isolation. The phase instability due to vibration is about 62 mrad at one second when T R = 8 ms [23]. We use a relatively short Raman interrogation time T R = 7.8 ms to avoid the effects of vibration.…”

Differential interferometry using a Bose-Einstein condensate

“…In our current setup, two wave packets are generated, separating along the y-axis and serving as input for two MZIs, to measure the rotation component Ω x and the acceleration component a z , as shown in Figure 1a. Employing three perpendicular oriented optical lattices, as depicted in Figure 5a, this scheme can be extended to a quantum inertial measurement unit [35,45,46], successively detecting all three components of Ω and a by performing correlated interferometry. For all measurements, two wave packets with a relative velocity v sep are generated by double Bragg diffraction.…”