Condensed Matter Seminar: Strongly Enhanced Light-Matter Interactions Using Colloidally Synthesized Plasmonic Nanoantennas

Gleb M. Akselrod (Duke University): Control of the radiative properties of emitters such as molecules, quantum dots, and color centers is central to nanophotonic and quantum optical devices, including lasers and single photon sources. Plasmonic cavities and nanoantennas can strongly modify the excitation and decay rates of nearby emitters by altering the local density of states. I will describe our work in the groups of Profs. M. Mikkelsen and D. Smith on large enhancements of fluorescence and spontaneous emission rates of molecules and quantum dots embedded in plasmonic nanoantennas with sub-10-nm gap sizes. The nanoantennas consist of colloidally synthesized silver nanocubes coupled to a metallic film, separated by a ~10 nm spacer layer with embedded molecules and quantum dots. Each nanocube resembles a nanoscale patch antenna whose plasmon resonance can be changed independent of its local field enhancement. We directly probe and control the nanoscale photonic environment of the embedded emitters including the local field enhancement, dipole orientation and spatial distribution of emitters. This enables the design and experimental demonstration of Purcell factors ~1,000 while maintaining high quantum efficiency and directional emission. Finally, I will discuss progress on coupling colloidal quantum dots to the plasmonic nanopatch antennas in order to realize a fast (<GHz) single photon source.

Event Date: 
Thursday, September 11, 2014 - 11:30am
Event Location: 
Physics 298
Event Contact: 
Event Speaker: 
Gleb M. Akselrod