Bismuth and magnesium co-doped lithium niobate crystal, preparation method thereof and application thereof

A method for preparing bismuth and magnesium co-doped lithium niobate crystal, the method comprising the following steps:

• mixing the powders of Li2CO3, Nb2O5, Bi2O3 and MgO by grinding with a planetary ball mill, wherein molar ratio of [Li] and [Nb] is 0.90-1.00, wherein molar percentage of Bi2O3 in the mixture is 0.25-0.80%, and wherein molar percentage of MgO in the mixture is 3.0-7.0%,
• keeping the mixture at a constant temperature of 850° C. to decompose Li2CO3;
• calcining at 1150° C. to make the mixed materials take place full solid phase reaction so as to form a powder of bismuth and magnesium co-doped lithium niobate;
• compacting the powder of bismuth and magnesium co-doped lithium niobate;
• placing into a platinum crucible;
• and
• heating with medium-frequency induction so as to form bismuth and magnesium co-doped lithium niobate crystal along a C-axis direction by Czochralski method.