Emission redistribution from a quantum dot-bowtie nanoantenna

We present a combined experimental and simulation study of a single self-assembled InGaAs quantum dot coupled to a nearby (∼25 nm) plasmonic antenna. Microphotoluminescence spectroscopy shows a ∼2.4× increase of intensity, which is attributed to spatial far-field redistribution of the emission from the quantum dot-antenna system. Power-dependent studies show similar saturation powers of 2.5 μW for both coupled and uncoupled quantum dot emission in polarization-resolved measurements. Moreover, time-resolved spectroscopy reveals the absence of Purcell enhancement of the quantum dot coupled to the antenna as compared with an uncoupled dot, yielding comparable exciton lifetimes of τ∼0.5 ns. This observation is supported by numerical simulations, suggesting only minor Purcell-effects of <2× for emitter–antenna separations >25 nm. The observed increased emission from a coupled quantum dot–plasmonic antenna system is found to be in good qualitative agreement with numerical simulations and will lead to a better understanding of light–matter coupling in such semiconductor–plasmonic hybrid systems.