Periodical poling characteristics of congruent MgO:LiNbO3 crystals at elevated temperature

A structure for quasi-phase matching of large cross section using 5 mol % MgO-doped LiNbO3 (MgO:LN) crystal for high-power wavelength conversion was realized. We have found that the coercive field to invert polarization of the crystal reduces drastically with elevated temperature. The coercive field reduces to 1.2 kV/mm at 250 °C, which is about 1/4 compared with that for MgO:LN at room temperature (RT) and about 1/17 of that for LN at RT. 3 mm thick periodically poled MgO:LN has been fabricated with 30 μm period.