A study to optimise the temporal drive pulse structure for efficient XUV lasing on the J=0-1, 19.6 nm line of Ge XXIII

Short pulses of 100 ps FWHM duration at 1.06 mu m wavelength are used as the pump source for driving the J = 0-1, 19.6 nm, Ne-like germanium X-ray laser. Different combinations of short pulses are investigated and quantitatively compared. Configurations investigated include a single pulse, double pulses at 400 ps and 800 ps separation, single pulses with prepulses and double pulses with prepulses. Data are presented in the form of integrated energy measurements, and supported by modelling. The most efficient short pulse configurations are shown to be orders of magnitude more effective than pumping with nanosecond duration pulses. (C) 1997 Elsevier Science B.V.