Focused beam control in super-ASHURA KrF laser system

Beam smoothing techniques and focused beam profile control techniques for h igh efficiency KrF laser fusion are reported. We have developed 1D and 2D b roadband random phase (BRP) irradiation techniques. Our next idea is the co mbination of a laser oscillator with a wide beam divergence angle and phase plates. The wide divergence angle laser beam eliminates the speckle patter ns caused by the phase plates. Well characterized focal spot patterns have been observed with the front-end pulse of the Super-ASHURA KrF laser system . Amplification experiments are on going.