Up-conversion and fluorescence quenching processes studies in highly Pr3+-doped YAG waveguides

In this work we report on results of our spectroscopic investigations applied to highly Pr-doped YAG planar waveguides. The technology of liquid phase epitaxy (LPE), utilized for active waveguides preparation, provided us with a unique set of samples with active ions concentrations as high as 6 at.%, which is impossible to obtain in bulk YAG. This encouraged us to perform an analysis of main processes responsible for up-converted excitation of emitting levels and fluorescence quenching. Visible fluorescence spectra and corresponding decay profiles obtained under direct and up-converted excitation were examined for wide selection of activator concentrations. The time-dependent rate equation model has been developed in order to describe and better understand possible processes involved.