Time-resolved imaging of ultrafast laser pulse interaction with transparent materials

A study of femtosecond laser interaction with a range of transparent solids, such as glass, sapphire, and fused silica in femtosecond-to-nanosecond time domain is reported.. Time-resolved pump-probe microscopic imaging of femtosecond laser breakdown area in different transparent solids has been done. Both absorption and Femtosecond Time-resolved Optical Polarigraphy (FTOP) microscopy techniques were used. White continuum was used as a probe pulse. Strong filamented plasma absorption initially dominates, being replaced by refraction index variations in filament traces and blast wave at hundreds of picoseconds delays. Dynamics of transient absorption in K8 glass was for the first time precisely linked with the pump pulse passage observed by FTOP. Cylindrical blast wave generation was observed starting from 200 ps delays in K8 glass and silica and its velocity has been measured. Exponential decay time of laser-induced plasma in sapphire, both pure and Ti doped has been found.