Optical Anisotropy of Strongly Enhanced Sum Frequency Generation in (113)B GaAs/AlAs Coupled Multilayer Cavity

Abstract

We have investigated optical anisotropy of sum frequency generation (SFG) of two cavity modes realized in a (113)B GaAs/AlAs coupled multilayer cavity. The SFG signals were measured by simultaneous excitation of two cavity modes with an optical frequency difference of 3.3 THz using 100-fs laser pulses. The peak intensity of the SFG signal was more than 400 times larger than that of the second-harmonic generation signal from the (113)B GaAs bulk substrate. Large optical anisotropy depending on the polarization angle of the excitation laser was observed in the strongly enhanced SFG in the (113)B coupled cavity sample. The observed anisotropic behavior was well explained by the in-plane anisotropy of the second-order nonlinear polarization on the (113)B GaAs substrate.