Boosting molecular fluorescence with a plasmonic nanolauncher.

Molecular emission enhancement is generally obtained by proper coupling with external resonances. Here we propose the idea of a plasmonic nanolauncher, i.e., a metamaterial-inspired ultranarrow channel at cutoff. Its peculiar operation provides uniform phase and drastic amplitude increase all over the channel, allowing high emission enhancement independent of the position of an individual or group of molecules along the channel, and of its length and geometry. This may provide a fascinating mechanism for efficient molecular detection and enhanced optical fluorescence.