Invited Paper
Wedge Waveguides and Resonators with Integrated Colloidal Quantum Dots

Quantum optics involves the coupling of quantum emitters to their electromagnetic environment. Because this coupling is related to the concentration of the optical field, it is typically constrained by the diffraction limit of light. One way to circumvent this is by exploiting plasmonics, which uses surface plasmon polaritons (SPPs) instead of photons. However, despite the advantages of this approach, it has not yet been fully explored. It has been limited in large part by experimental difficulties in creating the necessary structures. We address this problem by combining state-of-the-art quantum emitters with plasmonic structures (waveguides and reflectors) that approach theoretical performance limits. We synthesize highly luminescent colloidal quantum dots (photoluminescence quantum yield >90%) and precisely place them on template-stripped silver wedge waveguides. We demonstrate efficient coupling of the quantum-dot emission into guided plasmonic modes in the waveguide. In addition, by adding efficient reflectors, high-Q plasmonic resonators are obtained. More generally, the flexibility and fidelity of the resulting quantum-plasmonic systems indicates that they will allow a broad set of nanoscale quantum optical measurements to be pursued.

dnorris@ethz.ch