In situ Micro-Raman Investigation of Spatio-Temporal Evolution of Heat in Ultrafast Laser Microprocessing of Glass

Abstract

We describe a micro-Raman spectroscopic study of temperature dynamics in glass during the irradiation of focused ultrafast laser pulses. In the experiment, femtosecond pulses followed by nanosecond Raman pump pulses were focused inside a sample. Back-scattered Stokes and anti-Stokes Raman signals were detected by a time-gated polychromator to directly probe local temperature in the sample. We found that the time evolution and spatial diffusion are consistent with thermal diffusion model, whereas their dependences on pulse energy are different in fused silica and borofloat glass.