Energy transfer and energy level decay processes of Er3+ in water-free tellurite glass

Abstract

This report details the fundamental spectroscopic properties of a new class of water-free tellurite glasses studied for future applications in mid-infrared light generation. The fundamental excited state decay processes relating to the 4I11/2→4I13/2 transition in singly Er3+-doped Tellurium Zinc Lanthanum glass have been investigated using time-resolved fluorescence spectroscopy. The excited state dynamics was analyzed for Er2O3 concentrations between 0.5mol% and 4mol%. Selective laser excitation of the 4I11/2 energy level at 972nm and selective laser excitation of the 4I13/2 energy level at 1485nm has established that in a similar way to other Er3+-doped glasses, a strong energy-transfer upconversion by way of a dipole–dipole interaction between two excited erbium ions in the 4I13/2 level populates the 4I11/2 upper laser level of the 3μm transition. The 4I13/2 and 4I11/2 energy levels emitted luminescence with peaks located at 1532nm and 2734nm respectively with luminescence efficiencies of 100% and 8% for the higher (4mol.%) concentration sample. Results from numerical simulations showed that a population inversion is reached at a threshold pumping intensity of ∼57kWcm−2 for a CW laser pump at 976nm for [Er2O3]=2mol.%.