BEAM RESHAPING BY USE OF SPATIAL SOLITONS IN THE QUADRATIC NONLINEAR MEDIUM KTP

We have demonstrated the transformation of elliptical beams into cylin drically symmetric beams through the formation of quadratic spatial so litons. By use of type II phase-matched second-harmonic generation in a KTP crystal, input elliptical beams with aspect ratios as large as 8 :1 were propagated through the KTP crystal, and they exited the crysta l as a cylindrically symmetric beam. The threshold for soliton formati on and the power throughput were measured versus ellipticity. (C) 1997 Optical Society of America