OPTICALLY PUMPED RUBIDIUM AS A FREQUENCY STANDARD AT 196 THZ

The performance of 196.0-THz (1529-nm) DFB lasers frequency-locked to absorption lines of a rubidium vapor optically pumped at 384.2 THz (78 0.2 nm) is studied. The absorption profiles of the pumped vapor are me asured under various conditions and compared with theoretical predicti ons. A bright resonance resulting from the cascade of two cycling tran sitions is characterized both experimentally and theoretically. The me asured frequency stability of a DFB laser frequency-locked to this lin e reaches a level of 2x10(-10) for an averaging time of 100 s when com pared to a similar laser locked to an acetylene line.