Electro-optic coefficient measurements : correction of electric-field inhomogeneities in the transverse configuration

The problem of electric-field inhomogeneities in the measurement of the electro-optic coefficient in the transverse configuration is well known. We present a simple way to solve these difficulties. It involves local measurements at several points along the transverse direction of the phase difference between two components of light traveling through the crystal. The electro-optic coefficient is simply calculated by integrating the phase shifts along the transverse profile. For this procedure one needs nothing but the value of the voltage applied to the crystal, and knowledge of the internal electric field is not necessary. Limits of application are discussed, and results are shown for photorefractive sillenite crystals.