Stable generation of high-order harmonics of femtosecond laser radiation from laser produced plasma plumes at 1 kHz pulse repetition rate

Wepresent a method for the creation of stable weakly ionized plasmas from laser ablation of solid targets using a 1 kHz pulse repetition rate laser, which can be used for stable high-order harmonic generation from plasma plumes. The plasma plumes were generated from cylindrical rotating targets. Without target rotation the intensity of harmonics in the 40-80 nm range drops by more than one order of magnitude during less than 10(3) shots, while, with rotation of the target at typically 30 revolutions per minute, stable emission of high-order harmonics from aluminum plasma plumes with variation of less than 10% was maintained for > 10(6) laser shots. (C) 2012 Optical Society of America