Mid-IR spectroscopy of Er3+doped low-phonon CsCdCl3and CsPbCl3crystals

Abstract

The mid-IR spectroscopic properties ofEr3+doped low-phononCsCdCl3andCsPbCl3crystals grown by the Bridgman technique have been investigated. Using optical excitations at∼800nmand∼660nm, both crystals exhibited IR emissions at∼1.55,∼2.75,∼3.5, and∼4.5µmat room temperature. The mid-IR emission at 4.5 µm, originating from the4I9/2→4I11/2transition, showed a long emission lifetime of∼11.6msforEr3+dopedCsCdCl3, whereasEr3+dopedCsPbCl3exhibited a shorter lifetime of∼1.8ms. The measured emission lifetimes of the4I9/2state were nearly independent of the temperature, indicating a negligibly small nonradiative decay rate through multiphonon relaxation, as predicted by the energy-gap law for low-maximum-phonon energy hosts. The room temperature stimulated emission cross sections for the4I9/2→4I11/2transition inEr3+dopedCsCdCl3andCsPbCl3were determined to be∼0.14×10−20cm2and∼0.41×10−20cm2, respectively. The results of Judd–Ofelt analysis are presented and discussed.