physics pp. 1001–1006 Electro-optical properties of tetragonal KNbO3

Abstract. Linear electro-optical tensor coefficients and optical susceptibility of tetrag-onal KNbO3 are calculated using a formalism based on bond charge theory. Results are in close agreement with the experimental data. The covalent Nb–O bonding network comprising the distorted NbO6 octahedral groups in the structure is found to be a major contributor to the electro-optic coefficients making these groups more sensitive to these properties than the KO12 groups. The orientations of the chemical bonds play an impor-tant role in determining these properties