High electro-optic kerr effect in (Bi,K,Na)TiO₃ relaxor single crystals

Abstract

This report discloses the electro-optic (EO) properties of a lead-free Bi_0.5(K_0.33Na_0.67)_0.5TiO₃ (33BKNT) single crystal. The 33BKNT single crystal has near zero initial birefringence at room temperature and is optically isotropic. Moreover, the temperature dependence of the crystal’s dielectric permittivity reveals its relaxor behavior. The 33BKNT single crystal shows a quadratic EO effect with an EO coefficient (Kerr coefficient) of 16 × 10⁻¹⁷ m²/V², which is higher than the Kerr coefficient in other lead-free EO materials at room temperature.