Multiphonon-based comparison of erbium-doped yttria in large, fine grain polycrystalline ceramics and precursor forms

We have studied the phonon-induced non-radiative decay in erbium doped yttria (Y2O3). The technique employed allows for the evaluation of potential ceramic and crystalline laser materials. The frequency of the dominant phonon that deactivates the fluorescing levels and an approximate prediction of 0 K lifetime can be determined. Results show no significant quantitative difference between very large grain polycrystalline (with grain size ∼200–500 μm) ceramic, fine grain polycrystalline (with grain size ∼0.3 μm) ceramic and the precursor powder (with ∼30 nm particle size) of Er3+ doped Y2O3, when it comes to the dominant phonon frequency and the phonon occupancy number.The results show that a correct evaluation of the final product can be made in the precursor stage of the process eliminating the need to proceed to crystalline or fully sintered ceramic form to evaluate the spectroscopic properties of the material. It should be noted that the powders must be carefully prepared and handled. Adsorbed species such as water can drastically change the effective lifetimes observed in powder samples.

► The multi-phonon theory was applied in a novel way to evaluate different forms of erbium doped yttria.
► Results show no significant quantitative difference between very large grain polycrystalline ceramic, fine grain polycrystalline ceramic and the precursor powder of Er3+ doped Y2O3.
► Results indicate correct spectroscopic evaluation of the final product can be made in the precursor stage eliminating the need to proceed to crystalline or fully sintered form.
► Handling of the powders was also found to have a major impact. Adsorbed species such as water can drastically change the lifetimes observed in the precursor powders.