Characterization of plasmas driven by laser wavelengths in the 1.064-10.6 $\mu$m range as future extreme ultraviolet light sources

Abstract

We characterize the properties of extreme ultraviolet (EUV) light source plasmas driven by laser wavelengths in the $\lambda_{\mathrm{laser}} = 1.064 - 10.6 $ $\mu$m range. Detailed numerical simulations of laser-irradiated spherical tin microdroplet targets reveal a strong laser-wavelength dependence on laser light absorptivity and the conversion efficiency of generating EUV radiation. Radiative losses are found to dominate the power balance for all laser wavelengths, and a clear shift from kinetic to in-band radiative losses with increasing laser wavelength is identified. We find that the existence of maximum conversion efficiency, near $ \lambda_{\mathrm{laser}} = 4 $ $\mu$m, originates from the interplay between the optical depths of the laser light and the in-band EUV photons for this specific target geometry.