Abstract

In previous studies of soft-x-ray generation by irradiating solid Ta targets with 100 fsec, 620 nm pulses [1], we measured surprisingly low x-ray yields and deduced that rapid electronic diffusion carried the optically deposited energy from the front 100 Å skin depth of the target into the bulk even before the majority of the x-rays were emitted. In this work on carbon targets, we have shown that by eliminating diffusion into the bulk by geometrically constraining the laser excitation energy in a 100 Å film target, we get much higher total yield, shorter pulse durations and therefore more intense pulsed x-ray emission. Several groups [2,3,4,5] have recently begun to explore the physics of laser-heating solid density targets and the subsequent plasma evolution because the soft-x-ray pulses so generated can be used to pump x-ray lasers and to do time-resolved x-ray measurements directly.

© 1990 Optical Society of America