We have realized novel electrode configurations for efficient periodic poli
ng of ferroelectric crystals by applying a simple patterning method based o
n laser-induced material ablation. The new geometries mere theoretically in
vestigated and compared with conventional configurations. A systematic opti
mization of the patterning according to the ablated profile led to high-qua
lity quasi-phase-matched structures in lithium niobate with a grating perio
d of 20 mu m. The periodically poled samples were characterized by use of t
hird-order second-harmonic generation of a Nd:YAG laser. (C) 1998 Optical S
ociety of America.