Characteristics of second harmonic generation in GaAs plates

An experimental investigation was made of second harmonic generation by reflection from (111)- and (100)-cut GaAs surfaces. In the case of polished surfaces a considerable contribution to a nonlinear optical signal was made by reflection of YAG:Nd laser radiation from the rear surface. The advantages of diagnostics of the crystalline state on the basis of second harmonic generation in the transmission configuration were identified.