Limits on magnetically induced Faraday rotation from polarized He 3 atoms

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 measurements of gyromagnetic Faraday rotation on a dense, hyperpolarized He3 gas target. Theoretical calculations predict the rotations of linearly polarized light due to the magnetization of spin-1/2 particles on the scale of 10-7 radians. To maximize the signal, a He3 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.