Cooperative energy transfer in Tm3+ and Yb3+ co-doped phosphate glasses

An efficient near-infrared (NIR) quantum cutting (QC) in Tm3+ and Yb3+ co-doped phosphate glasses was demonstrated, which involved the emission of two NIR photons from an absorbed visible photon via a cooperative energy transfer (CET) from Tm3+ to Yb3+ ions. Judd-Ofelt (J-O) theory was used to calculate the intensity parameters (Ω2, Ω4, Ω6), the radiative transition rates (Ar), and radiative transition lifetime (τrad) of Tm3+. Based on Inokuti-Hirayama's model, the energy transfer processes were studied and results indicated that the energy transfer of the electric dipole-dipole (Edd) was dominant in this system. Quantum efficiency related to Yb3+ concentration was calculated, and the maximum QE efficiency reached 169.8%.