Photoemission with laser-generated harmonics tunable to 80 eV

I describe the generation of broadly tunable harmonic photons with energies to 80 eV hom a laser system that produces 200-fs pulses of 0.5-mJ 610-nm light at a repetition rate of 540 Hz. The harmonics are produced by focusing of the 610-nm light into high densities of rare gas atoms produced at the output of a pulsed valve. Harmonic photons are wavelength selected by a grazing incidence toroidal grating and refocused onto samples that reside in a vacuum analysis chamber. Valence and atomic core-level photoemission spectra generated with this light are described. (C) 1996 Optical Society of America