Figure 5.

MULTI-fs hydrodynamic simulations irradiated by a p-polarized laser pulse with a duration of 50 fs, a wavelength of 800 nm, and a laser intensity of (a,b) $8\times {10}^{14} \mathrm{W}/\mathrm{c}{\mathrm{m}}^2$ and (c,d) $8\times {10}^{15} \mathrm{W}/\mathrm{c}{\mathrm{m}}^2$, respectively. Time delays are (a,c) 0.5 ps, (b) 7.75 ps and (d) 2.7 ps, respectively. The ML structure is the same as the experiment. (e,f) 1D Particle-in-cell PICLS simulation results at time delays of (e) 1.5 and (f) 2.7 ps, respectively. In all figures, the yellow, grey, and red regions represent the laser-induced pressure wave (in Mbar or Mbar$/10$), mass density (in $\mathrm{g}/{\mathrm{cm}}^3$), and electron temperature (in eV), respectively. The dashed line denotes the initial sample density. The red arrow in (a) indicates the direction of the incoming laser.