Optically and thermally induced changes of structure, linear and non-linear optical properties of chalcogenides thin films

The spectral dependence of third-order non-linear susceptibilities, chi((3)), of amorphous As-S thin films was evaluated from changes of index of refraction using Miller's rule. The exposure of thin fresh evaporated films and their annealing increases chi((3)) it increases also their homogeneity and level of their polymerization as can be judged from Raman spectra of the films. The large covalently bonded parts ('molecules') of the samples are apparently favorable for increase of chi((3)) (C) 2003 Elsevier B.V. All rights reserved.