LASER IRRADIATION STUDIES OF TE-SE-BR GLASSES

We have studied the effect of laser irradiation on Te-Se-Br thin films. The major effect has been found to be dominated by changes in composition which include different morphologies. These changes are analysed by quantitative transmission electron microscopy (TEM) and scanning electron microscopy (SEM) as well as real time optical reflectivity. The measured losses of Br and Se are reasonable in view of the temperatures obtained from heat flow calculations for different laser pulse length and laser power conditions. When crystallization occurs, we have been able to establish that it starts with surface filamentary growth which exhibits fractal network formation. With higher laser energy, the filaments tend to coalesce to form metallic three dimensional crystals.