Electro-optical characterization of Pb(Zr,Ti)O₃ thin films by waveguide refractometry

Electric field-induced changes in the extraordinary and ordinary refractive indices of a Pb(Zr_0.53Ti_0.47)O₃ thin film were independently determined using waveguide refractometry. Under an electric field, applied normal to the film plane and corresponding to saturation of the electric polarization, the ratio of the extraordinary to ordinary refractive index change (Δn_e/Δn_o) is found to be -4/1, contributing to a net birefringence change [Δ(n_e-n _o)] of -0.021. Using this technique, both diagonal and off-diagonal elements of the electro-optic response tensor describing the macroscopic behavior of the polycrystalline film were accessed, illustrating the importance of this approach in evaluating orientation-specific electro-optic characteristics in these films.