Electromagnetically induced transparency (EIT) amplitude noise spectroscopy

Abstract

Intensity noise cross-correlation of the polarization eigenstates of light emerging from an atomic vapor cell in the Hanle configuration allows one to perform high resolution spectroscopy with freerunning semiconductor lasers. This shows promise as an inexpensive and simpler approach to magnetometry and timekeeping, and as a probe of dynamics of atomic coherence in warm vapor cells. We report here that varying the post-cell polarization state basis yields intensity noise spectra which reveal details about the prepared atomic state. We advance and test the hypothesis that the observed intensity noise can be explained in terms of an underlying stochastic process in light field amplitudes themselves. Understanding this stochastic process in the light field amplitudes themselves provides an additional test of the three level system model of EIT noise.