Laser interferometry based on atomic coherence

We demonstrate laser interferometry based on phase difference between the two arms of an interferometer. The experiments are done with a Cs atomic vapor cell at room temperature and use atomic coherence. The interference can be tuned from constructive to destructive by tuning the relative phase between the two arms. It is similar to the Michelson interferometer, but differs in the important aspect of allowing interference when the polarizations in the two arms are orthogonal. This would be a novel method for interfering two independent lasers, which can even allow interfering two independent lasers of completely different wavelengths.