Beam shaping of high-power laser beams by aberrated lenses: numerical simulation

A laser beam with a flat-top is desired in many applications, such as laser fusion, laser radar, laser heat treatment, etc. Unfortunately, the laser device operated in TEM/sub 00/ mode delivers a laser beam with Gaussian profile. Therefore beam shaping that reshapes a laser beam from Gaussian profile, into flat-top is very important. We theoretically prove that, by using a lens with negative spherical aberration (SA), one can reshape a partially coherent light beam with Gaussian profile into a flat-top. As a special case, we consider that the partially coherent light beam as a Gaussian Schell-model (GSM) beam with Gaussian profile of both the optical intensity and the degree of coherence. The numerical results show that after focusing by the lens with negative spherical aberration, the partially coherent light with flat-top can be achieved.