Ultrahigh-brightness laser beams with low prepulse obtained by stimulated Raman scattering

A unique high-power laser system is described that is based on stimulated Raman scattering in methane. KrF-laser pump beams of 10-ps duration are confined in a square-section light guide and amplify a 268-nm Stokes-shifted beam to 0.5 TW with extremely low prepulse. The near-diffraction-limited beam quality gives a peak brightness of >1020 W cm−2 sr−1.