Tuning the ED and MD transitions in Europium in a Fabry-Perot cavity
Jasper Landman
Abstract
Radiative transition rates are known to be tunable by changing the photonic environment of a fluorescent species. In this work, we investigate the influence of nearby metallic interfaces on the transition rates of Eu3+ ions. Specifically, we consider the magnetic dipole (MD) and electric dipole (ED) transitions that are visible in the luminescence spectrum of Eu3+ ions, which respond differently to a change in the photonic environment. Three different fabrication processes were used to prepare layered substrates with Eu3+ at a variable distance above a gold or silver mirror, or sandwiched between two gold or silver mirrors.\n\nA complete theoretical description of these layered substrates, using a Dyadic Green's formalism, is presented, leading to a set of directly applicable formulae. These formulae were found to provide very accurate predictions of the single mirror system spectra. The photoluminescence lifetimes of Eu3+ in these systems could not be reproduced: different factors seem to play a role here.\n\nThe quality of the emitting layer was found to have a significant effect on the fluorescence behaviour. A scattering emitting layer causes the emission coherence to be lost quickly, giving unpredictable results. Thermal treatment results in a very clear emitting layer, but emission brightness is reduced up to the point where no reliable spectrum could be recorded anymore for double mirror systems. Better control over the fabrication of the emitting layer is needed.