Stoichiometric Mg:LiNbO3 as an effective material for nonlinear optics

Photorefractive damage, optical absorption, photoconductivities, and photogalvanic currents of stoichiometric LiNbO3 single crystals with different Mg doping levels have been investigated. Nominally pure stoichiometric LiNbO3 shows lower photorefractive damage resistance than congruent crystal; however, stoichiometric crystals doped with MgO of more than 1.8 mol.% exhibit no measurable photorefractive damage at 532 nm to intensities of as much as 8 MW/cm(2). This remarkable damage resistance can be attributed not only to increased photoconductivity but also to decreased photogalvanic current. Stoichiometric Mg:LiNbO3 also demonstrates the shortest absorption edge, 302 nm, and a single-domain nature with low scattering losses. (C) 1998 Optical Society of America.