Efficient second Stokes Raman conversion in hydrogen

Abstract

We report cascade Raman generation of 313-nm radiation by second Stokes Raman shifting 248-nm pulses in H2. A single seed generator was used to produce the first and second Stokes seed beams. Both collinear- and crossed-beam amplifier configurations were investigated. A peak conversion efficiency of 43% was obtained in a 2-m amplifier cell containing 16 atm of hydrogen. Under optimized conditions, the phase front of the second Stokes beam exhibited only a fraction of a wave of aberration. We find that a trade-off between high beam quality and high conversion efficiency exists in a system that relies on a single seed generator.