2 research outputs found
Deep-Subwavelength Plasmonic Nanoresonators Exploiting Extreme Coupling
A metal–insulator–metal
(MIM) waveguide is a canonical structure used in many functional plasmonic
devices. Recently, research on nanoresonantors made from finite, that
is, truncated, MIM waveguides attracted a considerable deal of interest
motivated by the promise for many applications. However, most suggested
nanoresonators do not reach a deep-subwavelength domain. With ordinary
fabrication techniques the dielectric spacers usually remain fairly
thick, that is, in the order
of tens of nanometers. This prevents the wavevector of the guided
surface plasmon polariton to strongly deviate from the light line.
Here, we will show that the exploitation of an extreme coupling regime,
which appears for only a few nanometers thick dielectric spacer, can
lift this limitation. By taking advantage of atomic layer deposition
we fabricated and characterized exemplarily deep-subwavelength perfect
absorbers. Our results are fully supported by numerical simulations
and analytical considerations. Our work provides impetus on many fields
of nanoscience and will foster various applications in high-impact
areas such as metamaterials, light harvesting, and sensing or the
fabrication of quantum-plasmonic devices
Plasmon Coupling in Self-Assembled Gold Nanoparticle-Based Honeycomb Islands
Metallic nanostructures that sustain
plasmonic resonances are indispensable
ingredients for many functional devices. Whereas structures fabricated
with top-down methods entail the advantage of a nearly unlimited control
over all plasmonic properties, they are in most cases unsuitable for
a low cost fabrication on large surfaces; and eventually a truly nanometric
size domain is difficult to reach due to limitations in the fabrication
resolution. Although ordinary bottom-up techniques based on colloidal
nanolithography promise to lift these limitations, they often suffer
from their incapability to self-assemble nanoparticles at large surfaces
and at a density necessary to observe effects that strongly deviate
from those of isolated nanoparticles. Here, we rely on the application
of sequential bottom-up fabrication steps to realize honeycomb structures
from gold nanoparticles that show strong extinction bands in the near-infrared.
The extraordinary properties are only facilitated by densely packing
the nanoparticles into clusters with a finite size; causing the clusters
to act as plasmonic macromolecules. These strongly interacting bottom-up
materials with a deterministic geometry but fabricated by self-assembly
might be of use in future sensing applications and in material platforms
to mediate strong light–matter-interactions