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 μm diameter and up to 5 mm length were irradiated at $6\times {10}^{15}\mathrm{W}\mathrm{}\mathrm{c}{m}^{-2\mathrm{}}$. The time and space integrated gain coefficient on the 18.2 nm Balmer α transition was measured to be $12.5\pm 1.5{\mathrm{cm}}^{-1\mathrm{}}$. Comparison with numerical modeling suggests that saturated laser action would be obtained with less than a factor of 2 increase in length.