E-beam pumping and energy extraction from large-aperture KrF amplifiers

Experiments were performed at 100-J-class GARPUN KrF laser installation on optimization of e-beam pumping and amplification of 20-ns pulses in e-beam-pumped amplifiers with gain volumes of 10 X 10 X 100 cm and 16 X 18 X 100 cm(3). Amplified spontaneous emission (ASE) was measured in the near field close to the output window and in the far field along the amplifier axis. Suppression of transverse ASE by amplification of a laser signal was also investigated. The experimental data were compared with numerical simulations of e-beam transport using Monte Carlo code and 3-D numerical simulations of large-aperture single-pass and double-pass KrF laser amplifiers. Finally, the verified numerical codes were applied for optimization studies of large-scale KrF amplifiers with output energy up to 10 U being developed for Inertial Fusion Energy application.