Periodically poled second harmonic green light generation in near-stoichiometric MgO-doped LiNbO3 crystal

LiNbO3 crystal with different MgO doped concentration were processed by vapor transport equilibration.The processed crystals doped 2%(mole fraction) MgO increased the photoreactive damage resistance by at least 4 orders of magnitude compared with congruent crystal.By applying an external electric field of 4.5kV/mm,we obtained a periodically poled domain structure with a 6.8μm period and 1.0mm thickness in the doped MgO2%(mole fraction) near-stoichioment LiNbO3 crystal.A Q-switched Nd:YAG laser was used as the fundamental beam source at 1.064μm.When input power was 230mW,the green SHG at 0.532μm was obtained with 1.22% conversion efficiency.