Optical properties of Yb3+ ions in halogeno-sulphide glasses

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 2F5/2 and 2F7/2 states of Yb3+ 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 2F5/2 emission was determined from calculated and measured lifetimes. A quantum efficiency close to unity was found for Yb3+ emission at 77 K in Ge-In sulphide glass containing cesium iodide.