Enhanced Quantum Dot Spontaneous Emission with Multilayer Metamaterial Nanostructures

The Purcell effect of quantum dot (QD) spontaneous emission with Ag-SiO₂ multilayer metamaterial nanostructures has been demonstrated in experiment and simulation. A broadband enhanced spontaneous emission rate of QDs is observed due to large local density of states in the epsilon-near-zero and hyperbolic regions of multilayer structures. Multilayer gratings are utilized to further enhance the QD spontaneous emission as the QDs located inside the grating grooves strongly interact with high-k coupled surface plasmon polariton modes. Photoluminescence decay measurements are in good agreement with both analytical treatment with a nonlocal effect and three-dimensional finite-element simulation. Detailed studies of QD position and polarization effects on emission rate enhancement for multilayer and multilayer grating nanostructures provide important insight for understanding the coupling mechanisms of emitter-multilayer interaction and the engineering of local density of states in metamaterial nanostructures. These results will advance many applications in light-emitting devices, nanoscale lasers, quantum electrodynamics, and quantum information processing.