TRANSIENT GAIN ENHANCEMENT FOR PICOSECOND PULSES BY SUPPRESSING INTRACAVITY ASE IN A LARGE-APERTURE KRF LASER-AMPLIFIER

In a large-aperture amplifier, steady-state gain is heavily reduced by the intra-cavity amplified spontaneous emission (ASE). However, the r educed gain could be transiently enhanced by temporally suppressing th e ASE with an intense depleting short pulse. This transient gain enhan cement is experimentally studied in a 29-cm-diameter-aperture KrF lase r amplifier. The gain depleted by a 10-ps pulse is observed to recover more quickly to the initial steady-state gain level when the aperture of the amplifier is filled with the depleting beam than when only 3% of the aperture is filled.