摘要:
Device for providing a train of light pulses at Raman shifted frequency comprises a first ring laser (for fundamental frequency) and a second ring laser (for Raman shifted frequency). Both ring laser intersect in a Raman laser medium which is common to the cavity of both ring lasers. The Raman cavity has output means partially transmissive at Raman frequency. Length of first and second ring laser cavities differs by .DELTA.L. Injection of a fundamental pump pulse and a small Raman seed pulse into their respective cavities results in output of a train of Stokes pulses.