RESUMO
Tb-doped magneto-optical (MO) glass is widely used in fiber optics, optical isolators, and modulators. However, only the paramagnetic Tb3+ ions exhibit significant MO effects, whereas the diamagnetism Tb4+ ions suppress the MO effects. Therefore, the valence state control of Tb ions is very critical to optimize MO performance. Here, a reduction strategy was introduced to adjust the Tb valence in glass to achieve the high MO effect. The TiO, which has low valence Ti2+ ions and good reducibility, was used to suppress the oxidation of Tb3+ to Tb4+ ions. In the TiO-B2O3-Al2O3-Na2O glass, 10 mol% TiO can increase the Verdet constant at 650 nm by 19%. With the further increase in Tb2O3 concentration, the Verdet constant reaches a high value of 117 rad/(T·m) at 650 nm, which is close to the Verdet constant of TGG crystal (121 rad/(T·m)). This work provides a new approach to increase the Verdet constant of MO glass.