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×${10}^{15}$ W ${\mathrm{cm}}^{\mathrm{-}2}$. Maximum absorption of over 60% occurs for p-polarized radiation at angles of incidence in the range of 48°–57°. The measured results are in agreement with absorption on a steep density gradient.