Time- and Space-Resolved Optical Probing of Femtosecond-Laser-Driven Shock Waves in Aluminum

We present the first measurements of particle velocity histories at the interface between an aluminum sample shocked by a 120 fs laser-driven pressure pulse and a fused silica window. Frequency-domain interferometry is used to provide space- and time-resolved measurements of the phase shift of a pair of probe pulses backscattered at the shocked interface. Pressures of 1–3 Mbar are inferred from the simultaneous measurement of the particle and shock velocities along the aluminum Hugoniot curve for $\sim {10}^{14}\mathrm{W}/{\mathrm{cm}}^2$ laser irradiances.