Spectroscopic properties of Er3+ ions in transparent oxyfluoride glass ceramics containing CaF2 nano-crystals

In this paper, the spectroscopic properties of Er3+-doped oxyfluoride glass ceramics containing CaF2 nano-crystals are systematically investigated. X-ray diffraction (XRD) and transmission electron microscope (TEM) experiments confirmed the formation of CaF2 nano-crystals in the glassy matrix. Based on the Judd-Ofelt theory, the intensity parameters Omega(2,4,6), spontaneous emission probability, radiative life, radiative quantum efficiency, width of the emission line, stimulated emission cross-section and gain spectrum were evaluated, and the effect of Er3+ doping concentration on the spectroscopic properties of the I-4(13/2) -> I-4(15/2) transition is discussed. For glass ceramics, intense red and weak green up-conversion luminescence were observed and ascribed to two-photon absorption processes.