Abstract

Excitonic nonlinearity in wide-gap semiconductors has a strong possibility that we can realize efficient ultrafast optical interactions. Recently, we have observed very large third-order nonlinear phase shift in ZnSe layers grown by MBE on GaAs substrate [1], The third-order nonlinear susceptibility at exciton resonance is more than 10^–2 esu at 10 K. Because of the biaxial strain, the valence band splits into a heavy- and a light-hole branches at Γ point [2]. To clarify the intrinsic nature of excitonic nonlinearity, the materials which are free from such strain are preferable. In this report, we present our experiments on excitonic nonlinearity using ZnSe homoepitaxial layers which are free from the strain effects [3], and discuss the origin of enhanced nonlinearity at exciton resonance in ZnSe.

© 1992 Optical Society of America