Abstract

It is well established that biexcitons can be generated directly by two-photon absorption in CuCI. The intensity dependent nonlinearity arising from this resonance can be used to obtain optical bistability. Recently, Koch and Haug⁽¹⁾ and also Hanamura⁽²⁾ have predicted the possibility of a bistable operation in a CuCI Fabry-Perot etalon. Hanamura uses a density matrix formalism and predicts that the switching can respond in a picosecond time scale due to the virtual formation of biexcitons. Koch and Haug obtain the complex dielectric function from a Green's function formalism and suggest a bistable behavior for a thin CuCI slab. They use a constant value for the biexciton linewidth, γ_xx, and a zero value for the exciton linewidth, γ_x. Their results indicate that a 1-μm-thick CuCI etalon, with natural reflecting surfaces, can give rise to bistability with a switch-on intensity of about 0.1 MW/cm². The biexciton resonance, however, is located on the tail of the exciton resonance, which acts as a background absorption.

© 1983 Optical Society of America