UCLA

This thesis reports the experimental study of a new, promising class of solid- state laser gain media, namely erbium doped ceramic yttria. Optical quality ceramics have numerous advantages over single-crystal hosts and glass hosts, such as general mechanical robustness in extreme conditions, the ability to engineer doping profiles and tailor the laser gain media, and depending on the material system chosen, higher thermal conductivity these materials demand greater attention of researchers in the field. Ceramic gain media can also be made in large volumes much like glass, leveraging cheap flash-pumping methods to generate very high powers for military and scientific purposes.

The work reported here spans many areas that when taken together present a full evaluation of a future laser host. We have experimentally ascertained thus far the refractive indices of varying doping levels of active ion erbium in polycrystalline yttria and the materials stress-optic behavior. Spectroscopic data such as absorption and emission spectra in the near and mid infra-red regions, and the calculated cross-sections are also included. Multiphonon studies were also completed, the data provides vital information on the dominant phonon frequency and the radiative lifetimes. Energy transfer amongst the erbium ions and upconversion behavior is also analyzed. The theoretical work provided included an up-to-date Judd-Ofelt analysis of the ion-host system.

The multiphonon analysis above was expanded to include some other oxide host materials and differing forms of the same material. Some new upconversion pathways were also discovered in a novel two-pump experiment. Comparisons have been drawn to the current standard Er:YAG system where necessary.