Subdiffraction Light Concentration by J‑Aggregate Nanostructures

We
show, by accurate scattering calculations, that nanostructures
obtained from thin films of J-aggregate dyes, despite their insulating
behavior, are able to concentrate the electromagnetic field at optical
frequencies like metallic nanoparticles. These results promise to
widely enlarge the range of plasmonic materials, thus opening new
perspectives in nanophotonics. Specifically we investigate ultrathin
nanodisks and nanodisk dimers that can be obtained by standard nanolithography
and nanopatterning techniques. These molecular aggregates display
highly attractive nonlinear optical properties, which can be exploited
for the realization of ultracompact devices for switching by light
on the nanoscale without the need of additional nonlinear materials.