All-Optical Single-Species Cesium Atomic Comagnetometer with Optical Free Induction Decay Detection

TL;DR

This paper presents an all-optical single-species Cs atomic comagnetometer using optical FID detection, demonstrating suppressed systematic errors and setting competitive constraints on spin-gravity coupling.

Contribution

It introduces a novel all-optical single-species Cs comagnetometer based on optical FID, with improved error suppression and potential for more sensitive measurements.

Findings

Systematic errors from magnetic gradients and laser fields are highly suppressed.

Constraints on proton spin-gravity coupling are set at 10^{-18} eV.

Potential for further improvements with stabilization and optimization.

Abstract

Atomic comagnetometers, which measure the spin precession frequencies of overlapped species simultaneously, are widely applied to search for exotic spin-dependent interactions. Here we propose and implement an all-optical single-species Cs atomic comagnetometer based on the optical free induction decay (FID) signal of Cs atoms in hyperfine levels $F_g=3~\&~4$ within the same atomic ensemble. We experimentally show that systematic errors induced by magnetic field gradients and laser fields are highly suppressed in the comagnetometer, but those induced by asynchronous optical pumping and drift of residual magnetic field in the shield dominate the uncertainty of the comagnetometer. With this comagnetometer system, we set the constraint on the strength of spin-gravity coupling of the proton at a level of $10^{-18}$ eV, comparable to the most stringent one. With further optimization in magnetic field stabilization and spin polarization, the systematic errors can be effectively suppressed, and signal-to-noise ratio (SNR) can be improved, promising to set more stringent constraints on spin-gravity interactions.