Optical second-harmonic generation as a surface probe for noncentrosymmetric media

Abstract
We show that optical second-harmonic generation can also be used as an effective surface probe with a submonolayer sensitivity for media without inversion symmetry. The adsorption of Sn on GaAs is used as an example. A detailed summary of all accessible elements of the surface nonlinear susceptibility tensor χ(2) for the various crystal faces of GaAs is provided.