Short-Pulse Laser Absorption in Very Steep Plasma Density Gradients

We have measured the absorption of 1-ps laser pulses interacting with matter at intensities from {10}^{10}to {10}^{16}W/{\mathrm{cm}}^{2} The variations of absorption with incidence angle and polarization have been used to infer submicron plasma-density-gradient scale lengths. The results show a transition between a regime of laser interaction with sharply bounded dense cold matter...