Abstract

Recently McPherson et al.¹ reported strong, energetic emission(greater than 1 keV) from laser excited, krypton atoms in a pulsed gas source. Audebert et al.² observed Kα emission from argon in the interaction between a subpicosecond laser and the output of a gas jet. In both cases the emissions are anomalous in the sense that they derive from ions stripped to a higher charge state than predicted by tunneling theory. McPherson et al. postulate that this anomalous emission results from a new type of absorption in the clusters of Kr atoms, formed in the supersonic expansion of the gas nozzle. In this paper we present our observations of fluorescence from He-like and H-like neon, which does not condense into clusters under our experimental conditions. Our results can be simulated using a model that combines a laser-driven collisional excitation term with tunneling ionization.

© 1994 Optical Society of America