Limits on Magnetically Induced Faraday Rotation from Polarized $^3$He Atoms

TL;DR

This study attempted to measure magnetically induced Faraday rotation in hyperpolarized $^3$He gas, achieving high sensitivity but observing no detectable rotation, thus setting limits on such effects.

Contribution

First experimental attempt to measure gyromagnetic Faraday rotation in dense hyperpolarized $^3$He, providing upper bounds on the effect.

Findings

No observable Faraday rotation detected within experimental sensitivity.

Experimental setup achieved sensitivity of 10$^{-8}$ radians.

Results constrain theoretical predictions of magnetically induced Faraday rotation in $^3$He.

Abstract

Faraday rotation has become a powerful tool in a large variety of physics applications. Most prominently, Faraday rotation can be used in precision magnetometry. Here we report the first measurements of gyromagnetic Faraday rotation on a dense, hyperpolarized $^3$He gas target. Theoretical calculations predict the rotations of linearly polarized light due to the magnetization of spin-1/2 particles are on the scale of 10$^{-7}$ radians. To maximize the signal, a $^3$He target designed to use with a multipass cavity is combined with a sensitive apparatus for polarimetry that can detect optical rotations on the order of 10$^{-8}$ radians. Although the expected results are well above the sensitivity for the given experimental conditions, no nuclear-spin induced rotation was observed.