EUV spectral analysis of ns-laser produced bismuth plasmas at 8-17 nm.

ABSTRACT

Extreme ultraviolet (EUV) spectra from laser produced bismuth plasmas were recorded in the 8-17 nm spectral region using a NdYAG laser with a pulse length of 8 ns operating at a range of laser power densities. Due to the broad-band emission at 8-17 nm, bismuth plasmas show promise as sources of quasicontinuous radiation in the extreme ultraviolet. When varying the incident laser power density, ionic populations of Bi ions at different power densities were estimated by the collisional-radiative (CR) model for explanation of changes in the spectral profile. Comparison of experimental spectra with atomic structure calculations using the Hartree-Fock with configuration interaction (HFCI) code of Cowan was performed in order to identify most of the features in the spectra.