Optical properties of Yb3+ ions in halogeno-sulphide glasses

Abstract Ytterbium-doped low-phonon-energy glasses are promising materials for laser-induced cooling. In this context, the energies of Stark levels were established for the 2 F 5/2 and 2 F 7/2 states of Yb 3+ ions in glasses based on Ge, Ga or In sulphides associated with cesium chloride or cesium iodide. To do so, emission and absorption spectra, recorded at low temperature and room temperature, were deconvoluted. Quantum efficiency for the 2 F 5/2 emission was determined from calculated and measured lifetimes. A quantum efficiency close to unity was found for Yb 3+ emission at 77 K in Ge–In sulphide glass containing cesium iodide.