Optical orientation of dipolar centers in Bi_(12)SiO_(20) crystal grown in anoxygen-free atmosphere

摘要

In this paper, we report theoretical description and first experimental observation of recently predicted phenomenon called optical orientation of local centers with permanent dipole moment. An electrical current arising at periodical modulation of the polarization of incident light was observed in a crystal of Bi_(12)SiO_(20) grown in the argon atmosphere. Modulation frequency-dependence of the current amplitude allows us to attribute this current to the predicted effect. This deduction was additionally supported by our experimental data of light-induced dichroism and photoconductivity of the sample. Using a model of donor-acceptor pairs as dipolar centers we were able to explain features of optical orientation of dipolar centers in the crystal.