Spontaneous emission dynamics of Eu³⁺ ions coupled to hyperbolic metamaterials

We investigate a system comprising of Eu³⁺(NO₃)₃ nanocrystals on a hyperbolic metamaterial (HMM) structure featuring a hexagonal array of Ag-nanowires in a porous Al₂O₃ matrix. HMM-coupled Eu³⁺ ions exhibit up to 2.4-fold increase of their decay rate, accompanied by an enhancement of its ⁵D₀→⁷F₂ transition emission rate. Using FD-TD modeling, we corroborate these observations with the increase in the photonic density of states seen by the Eu³⁺ ions in the proximity of the HMM. Our results indicate HMMs can serve as a valuable tool to control the emission from weak transitions, and hence hint at a route towards more practical applications of rare-earth ions in nanoscale sensing and optoelectronic devices.

C. Indukuri, R. K. Yadav, J. K. Basu, “Broadband room temperature strong coupling between quantum dots and metamaterials” Nanoscale 2017, 9 (32), 11418.
Z. Jacob, I. I. Smolyaninov, E. E. Narimanov, “Broadband Purcell effect: Radiative decay engineering with metamaterials” Appl. Phys. Lett. 2012,100 (18), 181105.