Er3+-doped zinc tellurite glasses revisited: concentration dependent chemical durability, thermal stability and spectroscopic properties

Abstract

Tellurite glasses are interesting materials with extensive infrared transmission window, relatively low phonon energy, high refractive indexes and the ability to incorporate reasonably high amount of rare earth ion dopants. These characteristics make them popular candidates for infrared and visible emissions. Particularly, Er3 +-doped tellurite glass compositions have been actively studied for broadband near infrared applications where the requirement for low dimension needs to be compensated by higher doping ion concentration. In this work, we revisit Er3 +-doped zinc tellurite glasses, which are among the most thermally and chemically stable tellurite compositions. The glasses were prepared by the melt-quenching technique and the favorable effects of increasing dopant concentration on chemical durability, water resistivity and thermal stability (up to 140 °C) are discussed. The photophysical properties of the glasses were studied by absorption and luminescence spectroscopic techniques. The Stokes and anti-Stokes emissions of erbium were analyzed and it was verified that the width of the emission band at 1532 nm strongly depends on Er3 + concentration varying from 60 to 82 nm for 0.5 and 2.5 mol% of Er2O3, respectively. The intensity of green and red upconversion emissions was evaluated and the increased efficiency of red emission with increasing concentration is attributed to energy transfer mechanisms between infrared energy levels.