Controlling the Emission Rate of Er3+ Ions by Dielectric Coupling with Thin Films

The variation of local density of states and/or excitation of surface plasmons in proximity of a metal surface can be used to control the emission rate of Er-doped materials for optical and optoelectronic devices. In the present work we studied the modification of the radiative lifetime of Er3+ ions incorporated in silica layers by magnetron cosputtering, due to the interaction with metal (Ag, Au, Ti, and Cr) and semiconductor (Si), thin films. Photoluminescence measurements have shown in both cases a strong decrease of the erbium lifetime for the radiative transition at 1540 nm and a clear dependence on the distance between the film and the emitter up to 250 nm. A comparison between the effect of homogeneous thin films and nanostructured layers (nanohole arrays) has also been carried out. The results demonstrated that a high control over the radiative efficiency of the emitter can be achieved by a proper choice of the overlayer properties, and an increase of the radiative decay rate up to 300% has been experimentally measured.