We report discovery of recently predicted phenomenon, optical orientation by polar way of local centers with permanent dipole moment. In a crystal of Bi12SiO20 grown in the argon atmosphere electrical current arises when the polarization of incident light is periodically modulated. Dependence of the current amplitude on the modulation frequency allows us to attribute this current to the predicted effect, which is supported by the data on light-induced dichroism and photoconductivity of the sample. A model of donor-acceptor pairs as dipolar centers is shown to be able to explain main peculiarities of optical orientation of dipolar centers in the crystal.
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