Experimental study of second-harmonic generation by a laser pulse with varying direction of polarization in a type-II synchronism doubling crystal

An experimental study is performed of the type-II optical second-harmonic g eneration by a laser pulse whose direction of polarization experiences time variations. These variations are shown to result in considerable transform ations of the harmonic pulse. Under some conditions, significant shortening of the harmonic pulse is observed comparing the case of a launched pump pu lse with a fixed azimuth of polarization. The experimental data obtained wi th a KTP doubling crystal agree quite well with the results of theoretical modeling of the phenomenon. (C) 2001 Published by Elsevier Science B.V.