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 10¹⁴--2.5×{}10¹⁵ W cm^-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.