Gain and saturation intensity measurements of a mode-locked KrF oscillator-amplifier

The gain and saturation intensity of a fast-discharge KrF oscillator-amplifier have been investigated. The small-signal-gain coefficient was found to be 0.145 cm−1 for a 2-ns pulse and 0.160 cm−1 for a 10-ns pulse, with the respective saturation intensities ∼1.6 and ∼2.0 MW/cm2. An energy of 250 mJ was extracted with a 10-ns input pulse. It was possible to isolate by amplification a single 2-ns pulse from a mode-locked train (of 2 or 3 pulses) and to extract 35 mJ in the amplified beam.