Photoinduced birefringence in tellurite glasses

We report on photoinduced birefringence in TeO2-based glasses on exposure to linearly polarized subbandgap light. It is shown that the influence of glass-network modifiers, such as ZnO, Na2O, BaO, and of dopant Er2O3, on the photoinduced birefringence is not substantial indicating a dominating role of the TeO2 component. Photoinduced birefringence is optically reversible and its mechanism is proposed to be due to laser-induced alignment of intrinsic anisotropic defects of tellurite glass, such as distorted TeO4 bipyramids. (C) 2004 American Institute of Physics.