Enhanced frequency upconversion in Er-Yb codoped heavy metal oxides based tellurite glasses.

The spectroscopic investigations on the Er/Yb ions doped/codoped TeO-ZnO (TZ), TeO-ZnO-WO (TZW) and TeO-ZnO-WO-TiO (TZWTi) heavy metal oxide (HMO) glasses have been made. The absorption, photoluminescence, decay curve and Judd-Ofelt analysis have been performed to optimise the optical properties of the Er/Yb ions. The effect of incorporation of HMOs like WO and TiO in the Er/Yb doped/codoped TZ glass on its optical properties have been investigated. The enhancement in upconversion emission intensity has been explained on the basis of efficient energy transfer and inhomogeneous local field generation around the rare earth ions. The spectroscopic quality factor, absorption and stimulated emission cross-sections, optical gain, quantum efficiency (∼17.53%), energy transfer efficiency (∼61.64%), colour purity (∼94.7%) and ionic nature of the bonding have been determined. The Er-Yb-TZWTi glass can be used in visible lasers, yellowish green optical devices and home appliances.