Measurements of laser shock pressure and estimate of energy lost at 1.05-μm wavelength

Laser-driven shock pressures at 1.05-μm wavelength have been evaluated from measurements of shock transit time through aluminum foils by streak camera records of shock luminosity at the back face of the foil. An ablation pressure of 0.3 TPa is obtained for 1.2×1014 W/cm2 laser pulses focused on 300-μm spot diameter and 0.55 TPa for 3.5×1015 W/cm2 laser pulses focused on 60-μm spot diameter. These results, compared with theoretical values, show an important loss of energy, attributed to two-dimensional effects. The ratio of effective energy for compression to incident energy is estimated to be 12% for 1.2×1014 W/cm2 experiments and only 1% for 3.5×1015 W/cm2 experiments.