Multi-pass guided atomic Sagnac interferometer for high-performance rotation sensing

TL;DR

This paper proposes a multi-pass guided atomic Sagnac interferometer using Bose-Einstein condensates on a chip, overcoming coherence limitations to achieve high-precision rotation sensing comparable to free-space devices.

Contribution

It introduces a scheme for a multi-pass guided atom interferometer that overcomes intrinsic coherence limitations, enabling high-sensitivity rotation measurements in a compact chip-based device.

Findings

Estimated sensitivity of 45 nrads^{-1}Hz^{-1/2} for BEC-based gyroscopes.

Potential 2-4 orders of magnitude improvement over current free-space gyroscopes with BECs.

Further enhancement possible using thermal atoms for continuous operation.

Abstract

Matter-wave interferometry with atoms propagating in a guiding potential is expected to provide compact, scalable and precise inertial sensing. However, a rotation sensing device based on the Sagnac effect with atoms guided in a ring has not yet been implemented despite continuous efforts during the last two decades. Here we discuss some intrinsic effects that limit the coherence in such a device and propose a scheme that overcomes these limitations and enables a multi-pass guiding Sagnac interferometer with a Bose-Einstein condensate (BEC) on a chip in a ring potential. We analyze crucial dephasing effects: potential roughness, phase diffusion due to atom-atom interactions and number uncertainty, and phase fluctuations. Owing to the recent progress in achieving high momentum beam splitting, creating smooth guides, and manipulating the matter-wavepacket propagation, guided interferometry can be implemented within the coherence time allowed by phase diffusion. Despite the lower particle flux in a guided Sagnac ring and the miniaturization of the interferometer, the estimated sensitivity, for reasonable and practical realizations of an atom chip-based gyroscope, is comparable to that of free-space interferometers, reaching 45 nrads^{-1}Hz^{-1/2}. A significant improvement over state-of-the-art free-space gyrocope sensitivities can be envisioned by using thermal atoms instead of a BEC, whereby the interferometer can be operated in a continuous fashion with the coherence limited by the scattering rate of the atoms with the background gas. Taking into account the sensitivity times length of the interferometer as the figure of merit which takes into account compactness, our configuration is expected to deliver a potential improvement of 2-4 orders of magnitude over state-of-the-art free-space gyroscopes for a BEC, and 4-6 orders of magnitude for thermal atoms.