Abstract
A significant increase, as well as a decrease, in the intensity of single higher harmonics of femto-second radiation of a Ti:sapphire laser that are generated in a weakly excited laser plasma on the surface of GaAs. Cr, InSb, In, nd stainless steel is demonstrated. The intensities of some higher harmonics in different regions of their plateulike distribution varied from a 23-fold excess over the intensity of the neighboring harmonics to the complete absence in the extreme ultraviolet spectrum. The specific features of a 200-fold increase in the intensity of the 13th harmonic generated in indium plasma are analyzed. These variations in the intensity distribution 4 harmonics in the plateau region are obtained by varying the chirp of laser pulses.