Plasmonic Coupling in Er ³⁺:Au Tellurite Glass

In this paper, we report on luminescence and absorbance effects of Er ⁺³:Au-doped tellurite glasses synthesized by a melting-quenching and heat treatment technique. After annealing times of 2.5, 5.0, 7.5, and 10.0 h, at 300 °C, the gold nanoparticles (GNP) effects on the Er ⁺³ are verified from luminescence spectra and the corresponding levels lifetime. The localized surface plasmon resonance around 800 nm produced a maximum fluorescence enhancement for the band ranging from 800 to 840 nm, corresponding to the transitions ⁴H _11/2 → ⁴I _13/2 (805 nm) and ⁴S _3/2 → ⁴I _13/2 (840 nm), with annealing time till 7.5 h. The measured lifetime of the levels ⁴H _11/2 and ⁴S _3/2 confirmed the lifetime reduction due to the energy transfer from the GNP to Er ⁺³, causing an enhanced photon emission rate in these levels.