Optical frequency filtering for Raman beams.

We present an optical filter that is appropriate for use with Raman beams in atomic interferometry. This is a filter that lets the light of the two frequencies of the Raman pair go through and rejects spurious frequencies that may be close to the atomic resonance and cause decoherence. We characterized the filter's performance optically and also by shining the light into atoms in a Ramsey sequence, to look for decoherence effects from photon scattering.