Detection of the contribution of the inverse flexoelectric effect to the photorefractive response in a bismuth titanium oxide single crystal

Relations determining the contribution of the inverse flexoelectric effect to the photorefractive response have been determined for the case of the interaction of a steady pump wave conserving left-hand circular polarization with a phase-modulated signal wave that has circular polarization of the opposite sign on the input face of a crystal that has the (100) orientation and symmetry group 23. The experimental studies of such an interaction in a Bi₁₂TiO₂0:Fe,Cu crystal make it possible to estimate its flexoelectric coefficient as f ₁₁ = 5.3 nC/m.