Field induced periodic poling is used to create >10 micron period stru
ctures in approximately 250 micron thick slabs of LiNbO3. Third order
quasi-phase-matched second harmonic blue light generation is demonstra
ted by free propagation of a 937 nm fundamental Gaussian beam in perio
dically poled LiNbO3, with a conversion efficiency of 0.2% / W cm.