Observations of the intense soft x-ray emissions from ultrathin Au films irradiated with high contrast laser pulses

Abstract

Observation of soft x-ray emissions from laser produced plasmas using ultra thin film targets has been carried out. Au ultra thin films deposited on silicon nitride membranes were irradiated with a high contrast Nd:glass laser pulses. The spectral properties of emitted soft x-rays were monitored with an x-ray spectrograph from the membrane side. The observed emission intensities had a clear dependence on the Au film thickness. The results suggest that most of the laser energy irradiated is absorbed by the Au films and few of the energy goes into the silicon nitride membranes, which means an efficient laser energy deposition to the ultra thin Au film target and a high energy conversion rate from laser to x-rays.