Spatially localized UV-induced crystallization of SnO2 in photorefractive SiO2-SnO2 thin film

We report on the formation of spatially localized crystals in SiO 2-SnO2 thin films fabricated by the sol-gel technique. This material presents an intense absorption band (??10 3cm-1) in the UV region. A continuous wave UV laser operating at 266nm focused through a microscope objective is used as an effective tool to modify locally the matrix containing photorefractive SnO 2. The UV micro-Raman spectrometer is used to study the evolution of SnO2 crystals in the thin film. The appearance of the Raman scattering peak at 621cm-1, assigned to the A1g mode of rutile SnO2, confirms the formation of nanocrystals in the focalised UV irradiated zone. © 2010 Copyright SPIE - The International Society for Optical Engineering.