Simultaneous Two-Photon Absorption and Second Harmonic Generation in CdSe

CdSe is a hexagonal crystal of 6mm point symmetry. Two-photon absorption (TPA) and second harmonic generation (SHG) occur simultaneously when picosecond light pulses of a Nd:glass laser (wavelength 1054 nm) are passed through the crystal. Two-photon absorption coefficients determined previously are collected in ref.1. The contribution of the resonant non-phasematched second harmonic generation to the pump pulse transmission through CdSe [2] has not been studied in detail.