Short-pulse amplification in an F_2 gain module

We report on what is to our knowledge the first subpicosecond-pulse amplification experiments in an F2 gain module at 157 nm. 500-fs seed pulses were produced by a four-wave mixing process in xenon by excitation with KrF short-pulse radiation. The amplification experiments yield a small-signal gain coefficient of ~5%/cm and an estimate for the saturation energy density of approximately 180 μJ/cm2. For a single-pass amplification, an output energy of 60 μJ has been measured so far. From the spectral width of the amplification spectra, a minimum possible duration of ~200 fs for the amplification of short pulses can be estimated.