DEMONSTRATION OF HIGH-GAIN IN A RECOMBINATION XUV LASER AT 18.2 NM DRIVEN BY A 20-J, 2-PS GLASS-LASER

An exceptionally high gain coefficient has been obtained at 18.2 nm in a C VI recombination laser driven by a 2 ps, 20 J, Nd-glass laser operating by chirped pulse amplification. Carbon fiber targets of 7 \ensuremath{\mu}m diameter and up to 5 mm length were irradiated at $6\ifmmode\times\else\texttimes\fi{}{10}^{15}\mathrm{W}\mathrm{}\mathrm{c}{m}^{\ensuremath{-}2}$. The time and space integrated gain coefficient on the 18.2 nm Balmer \ensuremath{\alpha} transition was measured to be $12.5\ifmmode\pm\else\textpm\fi{}1.5{\mathrm{cm}}^{\ensuremath{-}1}$. Comparison with numerical modeling suggests that saturated laser action would be obtained with less than a factor of 2 increase in length.