We investigated the generation of high-order harmonics of a KrF excimer laser (80 mJ, 0.5 ps) in rare gases (He, Ne) and molecular gases (N2, O2). The highest-order harmonic, 7.1 nm, the 35th, was observed in He and Ne, and 8.6 nm, the 29th, in N2 and O2. Our experimental results suggest that the high-order harmonics are emitted from ionized atoms. The maximum photon energy of the high-order harmonics may be restricted by phase mismatching caused by free electrons.
© 1996 Optical Society of America
Original Manuscript: July 6, 1995
Published: January 1, 1996
Yutaka Nagata, Katsumi Midorikawa, Minoru Obara, and Koichi Toyoda, "High-order harmonic generation by subpicosecond KrF excimer laser pulses," Opt. Lett. 21, 15-17 (1996)