Applications of high-order harmonic generation

We present a review of recent research in Lund on applications of high-order harmonic generation, First, we have used high-order harmonics in spectroscopic studies of atoms and molecules. The experimental technique is based on a pump-probe scheme, where the pump pulse is a high-order harmonic synchronized with a laser pulse (probe). Short dissociation lifetimes in acetylene, as well as photoionization cross-sections from excited states of helium have been measured. In a second application, using the coherence of the high-order harmonic radiation, we have measured the electron density of a dense plasma, by an interferometry technique in the extreme ultraviolet region.