SSHG of uniaxial molecules: Phenomena near brewster's angle

The nonlinear optical behaviour of a crystalline adlayer of unidirectionally oriented macromolecules at a substrate is studied by means of the discrete dipole model. Polar and azimuthal dependence of the second harmonic pp-reflectance is investigated at the fundamental and second harmonic frequencies. The influence of the anisotropic linear properties of the adlayer turns out to be essential

Optical anisotropy of Ge(001)2x1

We have measured the change in the optical reflection anisotropy of a clean Ge(001) surface upon exposure to molecular oxygen up to saturation coverage. Both phase and amplitude changes have been recorded with a normal-incidence ellipsometer. They have been found to be related by a Kramers-Kronig transformation. The change in the complex reflection ratio could be interpreted as an anisotropy of the clean Ge(001)2 × 1 surface dielectric function, using a three-layer McIntyre-Aspnes approach and neglecting the oxygen overlayer. The surface dielectric function anisotropy can be described fairly well by optical selection rules, based on symmetry arguments. This model was applied to the possible optical transitions at this surface between filled dimers, dangling bonds and back-bonds and the empty dangling bonds and dimers

Optical anisotropy of Ge(001)

The surface induced optical anisotropy in the electronic structure of clean Ge(001) 2×1 was studied with an ellipsometer at normal incidence. The change in the reflection difference between light polarized parallel and perpendicular to the dimer bond at this surface upon either absorption of molecular oxygen or Ar+ ion bombardment was recorded. Both procedures were found to give the same results. It was possible to obtain a qualitative agreement of the optical spectrum recorded and the position and parity of the occupied and unoccupied surface states known on the clean surface