Optical Ring Cavity Search for Axion Dark Matter

TL;DR

This paper proposes a novel optical cavity experiment to detect axion dark matter by measuring phase velocity differences between circular polarizations, achieving unprecedented sensitivity for low-mass axions.

Contribution

It introduces a new null experiment design using a double-pass optical cavity to improve detection sensitivity for axion-photon coupling at very low axion masses.

Findings

Potential sensitivity to $g_{a extgamma}$ down to $3 imes 10^{-16}$ GeV$^{-1}$ for $m extless 10^{-15}$ eV.

The experiment surpasses current bounds by several orders of magnitude in the low-mass axion range.

Design achieves high common mode rejection of environmental disturbances.

Abstract

We propose a novel experiment to search for axion dark matter which differentiates the phase velocities of the left and right-handed polarized photons. Our optical cavity measures the difference of the resonant frequencies between two circular-polarizations of the laser beam. The design of our cavity adopts double-pass configuration to realize a null experiment and give a high common mode rejection of environmental disturbances. We estimate the potential sensitivity to the axion-photon coupling constant $g_{a\gamma}$ for the axion mass $m \lesssim 10^{-10}$ eV. In a low mass range $m \lesssim 10^{-15}$ eV, we can achieve $g_{a\gamma} \lesssim 3\times 10^{-16} ~\text{GeV}^{-1}$ which is beyond the current bound by several orders of magnitude.