Photoluminescence of Er3+ ions in Bi2TeO5 single crystals

Optical absorption and emission spectra of Er3+ ions in Bi2TeO5 single crystals have been studied at room temperature. Besides the H11/22→I15/24, S3/24→I15/24, and F9/24→I15/24, emission, that were typically strong under excitation to higher energy manifolds than the actual emission, the S3/24→I13/24 luminescence was also intense. The visible transitions were assigned, and Judd-Ofelt calculation was performed by fitting the experimental data set. The calculated Ωt Judd-Ofelt intensity parameters (Ω2=6.98±0.57×10-21 cm2; Ω4=1.74±0.05×10-21 cm2; Ω6=1.23±0.12×10-21 cm2) were consistent with the Bi2TeO5 crystal structure and the Er3+ substitution for Bi sites. The radiative transition probabilities, the branching ratios and the radiative lifetime of the transitions of Er3+ ions in bismuth tellurite were also calculated. The results are analyzed for potential application of Bi2TeO5:Er3+ as a new laser material.