Abstract

Most of experiments on harmonic generation in a gaseous medium use short incident wavelengths in order to obtain the shortest generated wavelengths¹⁻⁴. McPherson et al have reported up to the 17th harmonic in Ne using a 248 nm (KrF) excimer laser⁴ at an intensity of 10¹⁶ W/cm². This radiation corresponds to the emission of a photon around 15 nm, or a photon energy of 85 eV. It has been demonstrated^5,6 that high-order harmonics can be produced in a rare gas medium with laser photon energies more than 10 times smaller than the ionization energy.

© 1991 Optical Society of America