Absorption of femtosecond laser pulses in high-density plasma

The absorption of 250-fs KrF laser pulses incident on solid targets of aluminum and gold has been measured as a function of polarization and angle of incidence for the intensity range of ${10}^{14}$--2.5\ifmmode\times\else\texttimes\fi{}${10}^{15}$ W ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}2}$. Maximum absorption of over 60% occurs for p-polarized radiation at angles of incidence in the range of 48\ifmmode^\circ\else\textdegree\fi{}--57\ifmmode^\circ\else\textdegree\fi{}. The measured results are in agreement with absorption on a steep density gradient.