Domain inversion in LiTaO3 and LiNbO3 by electric field application on chemically patterned crystals

We report a process for the formation of inverted ferroelectric domain regions in LiTaO3 and LiNbO3. This process involves the chemical patterning of the material surface by diffusion of Ti or ion exchange followed by domain inversion by a uniform electric field. The resultant periodic domain structure is applicable to first order quasi-phase-matched second-harmonic generation (QPMSHG). In first order periodically poled crystals of Z-cut LiTaO3, initial results have shown bulk conversion efficiencies of up to 2%/(W cm). A second-harmonic conversion of 3 mW of blue wavelength power was observed from waveguide devices made on these crystals. (C) 1996 American Institute of Physics.