Enhanced stimulated Raman scattering in optical parametric oscillators from periodically poled KTiOPO4

Abstract

Enhanced Raman scattering and concurrent Raman oscillation have been observed in nanosecond optical parametric oscillators in the near-infrared spectral region for certain periodicities of periodically poled KTiOPO4. The increased Raman activity is associated with direct excitation of the phonon overtone band by the idler wave. The decrease in efficiency of stimulated Raman scattering at crystal temperature above 80 °C is explained by higher dephasing rate of coherently driven lattice polarization due to interaction with thermally generated phonons.