Nonlinear light absorption on the surface of a transparent wide-gap crystal: I. Direct interband transitions

Abstract

For a semi-infinite wide-gap crystal, expressions for the rates of one- and two-photon transitions caused by the action of linearly polarized light are obtained in the basis set of model surface and bulk functions. The transition probability is shown to significantly depend on the angle between the light polarization vector and the normal to the surface Ψ. At a light intensity of 10 MW/cm2, the probability of one-photon transitions between surface states is in the range 1024−1026 s−1 cm−2 (ψ = π/2 and ψ = 0, respectively). It is shown that, in the case wherein the light polarization vector is perpendicular to the surface, the rates of allowed n-photon transitions (n = 1, 2) decrease more slowly with increasing n than in the case in which the polarization vector lies in the plane of the surface.