Raman wavelength conversion in a multipass cell

Abstract : Positively chirped femtosecond pulses at 1030 nm are wavelength-converted using spontaneous and stimulated Raman scattering in a KGW crystal inserted inside a multipass cell. Recirculation in the cell and the Raman material allows both a high conversion efficiency and good spatial beam quality for the generated Stokes beams. The converted pulses can be compressed to subpicosecond duration. Multipass cells could be an appealing alternative to other Raman shifter implementations in terms of thermal effects, control of the Raman cascade, and overall output beam quality.