Quantum dot based detections of propagating plasmonic modes excited by bowtie antennas

Propagating plasmonic modes excited by bowtie apertures based on emissions from a layer of CdSe/ZnS quantum dots are experimentally detected. The mode distributions with a cladding of nm thick Al2O3 film in between the silver and the quantum dot layers are more homogenous compared to the uncoated structure. The variation discipline of the effective indexes and the decay lengths of the plasmonic modes are discussed for various refractive indexes and thicknesses of the cladding. The three dimensional field distributions of the structure are simulated and the plasmonic fields are only excited in and around the cladding layer on top of the silver film. Such quantum dots based detection methods are promising tools for simultaneous imaging of near field optical distributions in integrated plasmonic nano-circuits.