Abstract

High-order harmonic generation of an intense, short-pulse laser, provides a way of generating high-intensity radiation in the extreme ultraviolet (XUV) and soft X-ray spectral regions. Using the Ti:Sapphire terawatt laser in Lund (150 mJ, 150 fs at 794 nm), we have observed up to the 105th harmonic (7.6 nm) generated in He. This short-wavelength radiation has unique properties of short pulse length (~100 fs), high peak power and high spectral brightness. By focusing the harmonic radiation with suitable X-ray optics, it should be possible to obtain very high peak intensities. In this respect, high-order harmonic generation complement conventional sources of tunable XUV radiation, such as synchrotrons and laser-produced plasmas. To obtain the highest possible intensity after refocusing, it is important to maintain good temporal and spatial characteristics of the radiation as well as to optimize the number of harmonic photons generated.

© 1994 Optical Society of America