Time-Resolved Investigations and Biotechnological Applications of Plasmonic Nanostructures

Plasmonics exploits the collective motion of conduction electrons in metals (plasmons), thus
enabling light to couple with nanoscale objects, with the consequent generation of a plenty of novel
and unexpected optical effects and functionalities. Plasmonic nanostructures have been deeply
studied in the last decade due to their crucial impact on several areas of nanoscience and
nanotechnology. Their unrivalled capability to squeeze light well beyond its diffraction limit, leading
to extremely confined and enhanced electromagnetic fields on the nanoscale at optical frequencies, is
of great interest for the prospect of real-life applications, such as energy harvesting and photovoltaics,
wave-guiding and lasing, optoelectronics, fluorescence emission enhancement, plasmon-assisted biointerfaces
and nanomedicine. In this framework, traditional studies of the resonant behavior of
plasmonic nanoantennas rely on standard intensity detection schemes. Up to date, the temporal
dynamics of plasmonic nanoantennas remains challenging. In the first part of the talk we will show
that, by combining femtosecond time-domain spectroscopy and high-resolution confocal
microscopy, it is possible to measure full time- and field-resolved response of single plasmonic
nanoantennas [1]. In the second part of the talk, we will then show practical applications of plasmonic
nanostructures to single-molecule detection [2–4], enhanced spectroscopy on single-cells [5–7],
optical trapping [8,9], enhanced Raman scattering [10–12] and resonant energy transfer [13].