HOT-ELECTRON-PUMPED K-SHELL X-RAY LASER

Amplified spontaneous inner-shell emission produced via an ultrafast b urst of high-energy electrons from a femtosecond laser-produced plasma is proposed as a novel electron-pumped x-ray laser. In this scheme, a population inversion of the upper laser level is created via impact i onization of atomic inner shells by electron bombardment. Based on the requirement of a positive gain coefficient for amplifying spontaneous K-alpha line emission, a simple pumping threshold is found for the in cident electron flux, and feasibility of the scheme is assessed for a range of low-Z elements. (C) 1998 American Institute of Physics. [S002 1-3640(98)01110-4].