Spectroscopy and nonradiative phenomena of rare earths in glasses: Future applications

The radiative transition probabilities of rare earth ions in glasses can be calculated from the measured intensity parameters and calculated transition matrix elements using the Judd-Ofelt theory. The Judd-Ofelt parameters in oxide, flouride and chalcogenide glasses were obtained for a variety of rare earth ions. These intensity parameters depend on the chemical bonding between the rare earths and the glass matrix and the viscosity of the medium. The non-radiative transition probabilities are calculated using a phenomenological theory, experimentally measured fluorescence lifetimes and quantum efficiencies. The nonradiative transition probabilities show an exponential dependence on the phonon energy of the network-forming material. Experimental results according to this theory show that Er(III) has the highest quantum efficiency in fluoride glasses. Technological implementation of the above theory will be discussed for the lasers, sources for fiber waveguides and luminescent solar concentrators.