Abstract
Dependence of the electro-optic (EO) effect on grain size has been precisely investigated in lead lanthanum zirconate titanate (PLZT) transparent ceramics. The R (electric field-related) and g (polarization-related) coefficients are found to decrease drastically with decreasing grain size at around 1.7 μm, where a minimum in the EO R coefficient occurs. Two possible models are discussed to explain this significant change in the EO coefficients.