Picosecond optical probing of ultrafast energy transport in short pulse laser solid target interaction experiments

This paper reports observations of rapid energy transport effects resulting from high intensity laser heating of fused silica targets. Picosecond optical probing of these interactions provides information on the kinematics of supersonic ionization fronts driven into the targets. Studies have been conducted as a function of laser intensity, wavelength, and target angle. Additionally, targets with metallic surface layers have been investigated. Characterization of the laser absorption has enabled plasma and radiation hydrodynamics energy transport simulations to be implemented. Although consideration has been given to several energy transport mechanisms, including thermal and suprathermal electron transport, the kinematics are best explained with a radiation transport model. This is confirmed by angled and high and medium Z coated target experiments.