Calculation of temperature distribution induced by ultraviolet continuous wave laser exposure of silver-exchanged glass
Résumé
Silver nanoparticles embedded in glass matrix have attracted much interest because they confer optical properties to the glass that can be adjusted by varying the size, shape and packing density of the particles. We are previously demonstrated the growth of silver NPs in silver-exchanged soda-lime glasses by ultraviolet continuous wave laser irradiation. As reported elsewhere, this kind of cw irradiation leads to the formation of micro-lenses, due to local melting of the glass. Indeed, due to the locally high absorption of light, the glass is heated to temperatures higher than the glass transition temperature and after cooling, maintains the shape of a liquid droplet, which behaves as a micro-lens. In this work, we present the calculation of the temperature distribution induced by the irradiation of the glass which explains the shape of the droplet observed in our samples. Two parameters are required to perform the calculation: thermal conductivity and absorption coefficient of the glass. Since the measurement of the absorption coefficient remains tricky, it has been deduced from the calculations and then the temperature profile was optimized. From surface profile measurements, we determine the experimental radius of the micro-lenses for various powers. Finally, we calculate the temperature distribution of our samples for various powers. The maximum temperature, obtained in our case, varies between 1190 K and 1380 K for power from 100 mW to 130 mW, which is suitable for the formation of glass liquid droplets.