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

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 I-4(11/2) -> I-4(13/2) 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 0.5 mol% and 4 mol%. Selective laser excitation of the I-4(11/2) energy level at 972 nm and selective laser excitation of the I-4(13/2) energy level at 1485 nm 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 I-4(13/2) level populates the I-4(11/2) upper laser level of the 3 mu m transition. The I-4(13/2) and I-4(11/2) energy levels emitted luminescence with peaks located at 1532 nm and 2734 nm respectively with luminescence efficiencies of 100% and 8% for the higher (4 mol.%) concentration sample. Results from numerical simulations showed that a population inversion is reached at a threshold pumping intensity of similar to 57 kW cm(-2) for a CW laser pump at 976 nm for [Er2O3] = 2 mol.%. (C) 2015 Elsevier B.V. All rights reserved.