Noninvasive optical amplification and detection of Faraday rotation

The authors present a Mach-Zehnder-type interferometer with orthogonally polarized arms that passively, noninvasely, and optically amplifies Faraday rotation. At ambient temperatures, the interferometer, with an optical gain factor of ∼ 4.5 , outperforms the optical bridge (OB) technique with a detection limit of approximately 50 mrad , compared to 250 mrad for the OB, when both techniques are used for time resolved faraday rotation under similar experimental conditions. Isolation and active stabilization of the interferometer have reduced sources of noise so that the interferometer's signal is also quieter than the OB.