Analysis of the refractive indices of lithium niobate at high temperatures

摘要

The temperature dependence of the refractive indices of lithium niobate crystals of stoichiometric composition is analyzed. It is shown that, in the region of the ferroelectric phase, the electronic dipole polarizability of oxygen ions significantly depends on the crystal temperature. The difference in the refractive indices Delta n = n(e)-n(o) in the paraelectric phase at lambda = 1200 nm is determined to be 0.036 +/- 0.003.