Bulk crystal growth of congruent MgO-doped LiNbO sub(3) crystal with stoichiometric structure and its second-harmonic-generation properties

A new LiNbO sub(3) bulk crystal has been grown by doping with MgO (cs-MgO:LN; Li sub(2)O:Nb sub(2)O sub(5):MgO=45.30:50.00:4.70, (Li sub(0.906)Mg sub(0.047)V super(Li) sub(0.047))NbO sub(3)), which successfully has the congruent point coinciding with the stoichiometric point. Its second-harmonic-generation (SHG) properties were evaluated. It was found that cs-MgO:LN has a much more homogeneous composition leading to uniform in-plane distribution of the non-critical phase-matching wavelength than the conventional LiNbO sub(3) crystals such as congruent LiNbO sub(3) (c-LN), stoichiometric LiNbO sub(3) (s-LN), and MgO-doped congruent LiNbO sub(3) (5MgO:LN). This homogeneity arose from the observation that none of the solute components including ionic species were segregated at the interface during growth. The SHG conversion efficiency of cs-MgO:LN is comparable to those of s-LN and 5MgO:LN.