THEORY OF THE POLARIZATION DEPENDENCE OF 2-PHOTON ABSORPTION IN ZINCBLENDE SEMICONDUCTORS

The polarization dependence of two-photon absorption is calculated for several zinc-blende semiconductors. The spectral dependence of the linear/circular dichroism is determined using an isotropic, four-band Kane bandstructure model and is shown to have specific features associated with the split-off band. The crystalline orientational dependence is determined using an anisotropic band-structure model obtained by additionally including the next highest upper conduction band set. It is shown that the anisotropic behaviour of the two-photon absorption is small in InSb but is quite substantial in GaAs giving a variation in the two-photon absorption coefficient for linearly polarized light of around 70% at a wavelength of 1 mum.