Characterization of the Vacuum Birefringence Polarimeter at BMV: Dynamical Cavity Mirror Birefringence

TL;DR

This paper discusses the optical characterization of the BMV polarimeter, focusing on understanding dynamical birefringence caused by cavity mirror motion to improve measurements of vacuum birefringence predicted by QED.

Contribution

It presents the first investigation of dynamical birefringence in the BMV cavity due to mirror motion, advancing the understanding of noise sources in precision polarimetry.

Findings

Identified cavity mirror motion as a source of dynamical birefringence

Analyzed the impact of mirror motion on polarization ellipticity measurements

Provided insights to improve the sensitivity of vacuum birefringence detection

Abstract

We present the current status and outlook of the optical characterization of the polarimeter at the Bir\'{e}fringence Magn\'etique du Vide (BMV) experiment. BMV is a polarimetric search for the QED predicted anisotropy of vacuum in the presence of external electromagnetic fields. The main challenge faced in this fundamental test is the measurement of polarization ellipticity on the order of ${10^{-15}}$ induced in linearly polarized laser field per pass through a magnetic field having an amplitude and length ${B^{2}L=100\,\mathrm{T}^{2}\mathrm{m}}$. This challenge is addressed by understanding the noise sources in precision cavity-enhanced polarimetry. In this paper we discuss the first investigation of dynamical birefringence in the signal-enhancing cavity as a result of cavity mirror motion.