First-order quasi-phase matched LiNbO3 waveguide periodically poled by applying an external field for efficient blue second-harmonic generation

A novel method of fabricating a periodic domain structure with ideal laminar domains in LiNbO3 by applying an external field at room temperature is proposed. The method allows a high blue beam power of 20.7 mW and a high conversion efficiency of 600%/W cm2 to be obtained.