Abstract
The coupling of light into the free-electron gas in plasmonic nanostructures offers unprecedented control over optical material properties on the nanoscale. Losses in metal films, however, currently limit the feasibility of many applications. We investigate how the losses can be reduced by symmetry in hybrid organic/plasmonic waveguides or compensated by the energy transfer between excitons in semiconductor nanowires and plasmon oscillations of a deposited metal shell.
In my talk I report on the mode properties of guided light in aluminum-quinoline (Alq3) waveguides comprising one or three thin Mg:Ag layers. The investigations show that strategically placed metal films can be used to selectively excite plasmonic and dielectric-type waveguide modes. I will also present optical investigations on the exciton emission in zincblende GaAs-AlGaAs-GaAs nanowires and in wurtzite GaN nanorods which are coated with a few nanometer thick Alq3 film and a layer of gold nanoparticles. The Alq3 spacer layer between the nanowire and the gold layer is used to control the metal induced band-bending in the semiconductor and the energy-transfer from semiconductor excitons to plasmon oscillations. The energy transfer from excitons to plasmons has potential to design low-loss nanoplasmonic waveguides or plasmonic lasing devices.
Coffee and tea will be served 20 minutes prior to the seminar.
Anyone interested is welcome to attend.