Mid-infrared emissions and multiphonon relaxation in Dy 3+-doped chalcohalide glasses

Abstract

Effects of Br addition into Ge 25Ga 10S 65 glasses on the mid-infrared emissions and multiphonon relaxation of Dy 3+ were investigated. Measured lifetimes of three energy levels emitting the infrared fluorescences increased with the addition of Br. Temperature-dependence of the multiphonon relaxation rates ( W mp=1/ τ m − 1/ τ R at low concentration of Dy 3+) showed the dominance of 5-phonon relaxation process at 375 cm −1 vibration associated with the asymmetric stretching of GeS 4 tetrahedra. A decrease in the multiphonon relaxation rates with Br addition is associated with an increase of the width of the 6F 11/2– 6H 9/2 manifolds of Dy 3+. It resulted in thermal depopulation of the lowest Stark component and thereby, decreased the multiphonon relaxation rates in Br-containing glasses.