A KRF OSCILLATOR SYSTEM WITH UNIFORM PROFILES

A KrF oscillator system that has produced highly uniform flat-top foca l distributions is described. The oscillator system is part of a large laser system that will utilize the echelon-free induced spatial incoh erence technique to obtain uniform illumination of planar targets for fusion research. With this system, focal profiles with small long scal e length nonuniformities have been obtained. The nonuniformity was det ermined by performing a least-squares fit to a series of profiles, and calculating the deviation of each fit from a flat-top profile. With a linear fit, the deviation averaged over the series is +/- 0.5%, and w ith a quadratic fit, it is +/- 1.4%. Details of the oscillator system configuration, focal uniformity measurement techniques, and resulting focal profiles are presented.