Applied Nanophotonics, Liquid Crystals and Biomedical Optics

Quasi-periodic oscillations in the transmittance and in the Raman Scattering spectra of several amorphous materials has been observed as a function of exposure time when irradiated by relatively low intensity CW laser beams. These oscillations are due to structural transformations between metastable states through the time evolution of the material structure from the metastable amorphous state towards more ordered states and finally to the crystalline state. The quasiperiod and its dependence on the photon energy and laser power are explained within the framework of a kinetic many body model used recently to explain the recrystallization of a-Si.