Abstract

When an intense laser is focused into a gas jet, very high-order harmonics can be produced. The harmonics are emitted approximately with the same efficiency up to orders as high as 143 and to energies as high as 180 eV (6 nm). They have the same characteristics as the generating laser: they are collimated, intense, coherent and of short pulse duration. Thus, these phenomena are interesting not only from a basic point-of-view as a probe of the response of an atom to a strong laser field, but also, from a more applied point-of-view, as an interesting soft X-ray source, with specific properties. The radiation can be used in traditional applications in atomic, molecular and solid-state physics, such as lifetime measurements. More “exotic” applications, such as the production of attosecond (subfemtosecond) light pulses, have also been proposed. Both aspects, the understanding of the physics of harmonic generation, as well as the applications of this new XUV radiation source will be reviewed.

© 1996 IEEE