We report on the characterization of structural modifications created by micro-explosions at the beam waist of a tightly focused femtosecond laser pulse inside of GeO2 glass. Micro-Raman scattering revealed the presence of structurally strongly modified regions at and around the irradiated sites. For separations of 5 μm between adjacent irradiated sites structural modifications due to a pressure increase are observed, whereas smaller spacings of 2 μm lead to thermal effects and crystallization. The mechanisms and the interplay of pressure and temperature effects are discussed.
Journal of Non-Crystalline Solids: proceedings of the 11th Conference on the Structure of Non-Crystalline Materials (NCM11), Paris, France, 28 June-02 July 2010, Vol. 357, no. 14 (Jul 2011), pp. 2637-2640