The damage fluences of gratings for diffraction of ultraviolet radiation, which are used in high-order harmonic generation experiments, have been measured with respect to the fundamental laser beam radiation. We have tested gold and platinum coatings of 40- and 50-nm thickness, respectively, deposited onto fused-silica substrates, after irradiation of high-energy, spatially filtered, 20-fs laser pulses at 780 nm. The damage appears at a fluence of ∼0.3 J cm-2 for gold and at a fluence of ∼0.4 J cm-2 for platinum. Scanning electron microscopy of the irradiated regions revealed different damaging mechanisms for the two coatings.
© 1999 Optical Society of America
Original Manuscript: November 30, 1998
Revised Manuscript: March 12, 1999
Published: July 20, 1999
Paolo Ceccherini, Maria-G. Pelizzo, Paolo Villoresi, Sandro De Silvestri, Mauro Nisoli, and Salvatore Stagira, "Surface damage of extreme-ultraviolet gratings exposed to high-energy 20-fs laser pulses," Appl. Opt. 38, 4720-4724 (1999)