2004 Volume 32 Issue 4 Pages 241-246
This paper reviews a method of the irradiance profile smoothing on the high-power laser system. In the multi-beam laser irradiation geometry, the coherence control of laser beam is necessary to reduce the irradiation nonuniformity in the wide spatial frequency region. The laser beam with spatio-temporal phase modulation (STPM) provides a unique feature that it is nearly coherent in propagating amplifiers through a frequency converter, while it becomes partially coherent in a focal spot. Such a unique beam can be generated by a multi-stage optical system consisting of series of phase modulators and diffraction gratings.
