Abstract
The amplification of a 10 ps pulse by two-stage electron-beam pumped KrF laser amplifiers is reported. The energy of 4 J was obtained for the pulse, which is the largest energy ever reported for short pulse excimer lasers. Nearly 90% of the final amplifier (29cm diameter) was filled by the beam, and the energy density of the picosecond beam reached 3.9times the saturation energy density. 56% of the stored energy was estimated to be extracted to the pulse.
Measured energy of the amplified spontaneous emission (ASE) agreed well with the value estimated theoretically, and most of the ASE was observed to originate in the first amplifier. From the comparison of the measured energy, pulse duration, and divergence of the picosecond pulse to those of the ASE, the S/N ratio of the picosecond pulse to ASE is estimated to be as large as 105 in terms of the focused power density.
