Efficient Raman shifting of high-energy picosecond pulses into the eye-safe 1.5-µm spectral region by use of a KGd(WO4)_2 crystal

We report an efficient transient stimulated Raman conversion of high-energy picosecond pulses at 1350 nm into the eye-safe 1500-nm wavelength range by use of a KGd(WO4)_2 crystal. The conversion efficiency into either 1503- or 1537-nm radiation (767- or 901-cm^-1 Raman modes, respectively) is measured to be ~10% in a single-pass configuration. The transient Raman gain coefficient is found to be ~0.8 cm/GW. Simultaneous generation of multiple Raman lines is also observed.