Theory of electro-optic effect in the tetragonal phase of BaTiO3

Abstract
The microscopic mechanism of electro-optic effect in tetragonal phase of BaTiO3 is discussed taking account of the piezoelectric effect due to the lattice deformation and the spontaneous Kerr effect as to a cause of the to the strong local field acting in the constituant ions. It is found that the birefringence σn and the linear electro-optic coefficients (Pockels constants) r33 and r13 obtained are in good agreement with the experimental data.