Optical characterization and ligand-field splitting of Er3+(4f11) energy levels in a fluorine containing tellurite glass

Abstract

An in-depth spectroscopic study is performed on Er3+(4f11) ions doped into a fluorine containing (lead, lanthanum)-tellurite glass host, containing nominal 1.93at.% of Er3+. The standard Judd-Ofelt (JO) model is applied to the room temperature absorption intensities of Er3+(4f11) transitions in the tellurite glass host to obtain three phenomenological intensity parameters, Ω2, Ω4, and Ω6. These parameters are subsequently used to determine the radiative decay rates, radiative lifetimes, and branching ratios of the Er3+ transitions from the upper multiplet manifolds to the corresponding lower-lying multiplet manifolds LJ2S+1 of Er3+(4f11) in the tellurite glass host. The emission cross sections of the intermanifold Er3+ I13∕24→I15∕24 (1.5μm) and S3∕24→I15∕24 (540nm) transitions have been determined. The room temperature fluorescence lifetimes of the I13∕24→I15∕24 and S3∕24→I15∕24 transitions in this tellurite glass host were also measured. From the radiative lifetime determined from the JO model and measured fluorescence lifetime, the quantum efficiency of this material was also determined. The spectroscopic properties were compared with those of Er3+(4f11) in other halotellurite glass hosts. We also analyzed the band structure observed in the absorption spectra of Er3+ in the tellurite glass at 8K. The structure can be interpreted in terms of the ligand-field splitting of the energy levels of the Er3+ ion in the local environment established by the glass matrix into which Er2O3 has been introduced. The spectroscopic analysis of Er3+(4f11) suggests that the tellurite glass is an excellent candidate for various photonic applications.