Surface damage of extreme-ultraviolet gratings exposed to high-energy 20-fs laser pulses.
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 approximately 0.3 J cm(-2) for gold and at a fluence of approximately 0.4 J cm(-2) for platinum. Scanning electron microscopy of the irradiated regions revealed different damaging mechanisms for the two coatings.
Ceccherini
P
P
Laboratorio di Elettronica Quantistica, Istituto Nazionale Fisica della Materia, Universita di Padova, Padova, Italy.
Pelizzo
M G
MG
Villoresi
P
P
De Silvestri
S
S
Nisoli
M
M
Stagira
S
S