High gain recombination XUV lasers and efficient XUV harmonics from ps laser pulse interactions with solid targets

We present recent developments on high gain recombination XUV lasers and efficient XUV harmonics from solid targets using the CPA Vulcan laser beam at the Rutherford Appleton Laboratory (RAL). Following successful experiments on the hydrogen-like carbon recombination laser at 18.2 nm, high gain operation has also been demonstrated at 11.1 nm in the sodium-like copper recombination XUV laser by irradiating thin fibre targets at intensities of 6×l0¹⁵ Wcm^-2 with 2 ps laser pulses. This experiment has shown that 2 ps is the optimum pulse duration to drive the sodium-like copper laser. In addition to the recombination laser experiments, highly efficient harmonics up to 75th order at 14.0 nm have been observed in the interaction of 2 ps laser pulses with solid targets for intensities up to 10¹⁹ Wcm^-2. The conversion efficiency is estimated to be ≥ 10^-6 at 10¹⁹ Wcm^-2 for harmonic orders up to the 68th.