Time‐resolved evolution of laser‐produced plasmas in spherical expansion regime

We report experimental results deduced from quantitative Schlieren imaging of plasmas combined with streak camera recording. Flat or spherical targets are illuminated with one laser beam, at different wavelengths (1.06 μm, 0.53 μm, 10.6 μm): We show that time‐resolved density profiles are more stationary for shorter wavelength. We measure the rear displacement and front expansion of plasmas created on glass microballoons and solid microspheres. Comparison with hydrocode simulations shows that transport is inhibited for 1.06‐μm interaction, and that ablation processes are more efficient for shorter wavelength.