Electric field and temperature dependence of the birefringence in linbo₃

Abstract

In spite of the large utilisation of LiNbO₃ in optical devices for its non linear optical properties, its electrooptic coefficients surprisingly are not perfectly known. The electrooptic coefficient r_c of LiNbO₃ is determined by a technique issued from the Senarmont method. The measurements are performed for various values of the DC applied electric field as a function of the temperature around room temperature. We point out the drastic influence of the spontaneous birefringence variation due to the temperature change. Accurate, correct and reproducible values of the electrooptic coefficients can be obtained only if this dependence is taken into account.