This project is concerned with the optical spectroscopy of rare earth ions in solids which exhibit upconversion, namely the process of converting low energy photons into higher energy photons. These materials are of current interest because of recent developments in upconversion-pumped lasers. The focus of the work will be on the evaluation of potential new laser systems. The concentration dependence of energy transfer upconversion in yttrium aluminum trioxide doped with erbium ions will be studied by measuring the infrared to visible conversion efficiency. In addition similar measurements will be performed on yttrium oxide doped with erbium ions. The latter material has not yet been demonstrated as an upconversion laser material. A third material that will be studied is barium-yttrium fluoride doped with erbium ions.
