Using multiple pumps to study energy-transfer pathways in Er3+:Y2O3 ceramics

Erbium ions in inorganic, insulating gain media show a wide variety emission wavelengths - including ultra-violet, visible (red, green and blue), near-IR (∼800 nm, ∼980 nm, ∼1550 nm) and mid-IR (∼3000 nm). Erbium is an interesting ion providing multiple paths to emit multiple wavelengths. The energy levels corresponding to these wavelengths can be populated by converting lower-energy photons into higher energy photons by various energy-transfer mechanisms. Different energy-transfer mechanisms may be present at different concentrations of erbium in the insulating host matrix. Some of these mechanisms are difficult to prove experimentally. We present a novel approach to study utilizing a dual-pump scheme to elucidate some of the energy-transfer mechanisms/pathways in erbium-doped ceramic yttria. By dynamically changing the populations in intermediate energy-levels, we could track the energy-transfer paths, yielding information on the dynamic nature of energy-transfer in RE-doped materials. The parameters controlled in this study were the concentration of the active ion, the pump wavelengths and pump power.