nn9b05031_si_001.pdf (1.57 MB)
Analysis of the Limits of the Near-Field Produced by Nanoparticle Arrays
journal contribution
posted on 2019-09-11, 18:34 authored by Alejandro Manjavacas, Lauren Zundel, Stephen SandersPeriodic arrays are
an exceptionally interesting arrangement for metallic nanostructures
because of their ability to support collective lattice resonances.
These modes, which arise from the coherent multiple scattering enabled
by the lattice periodicity, give rise to very strong and spectrally
narrow optical responses. Here, we investigate the enhancement of
the near-field produced by the lattice resonances of arrays of metallic
nanoparticles when illuminated with a plane wave. We find that, for
infinite arrays, this enhancement can be made arbitrarily large by
appropriately designing the geometrical characteristics of the array.
On the other hand, in the case of finite arrays, the near-field enhancement
is limited by the number of elements of the array that interact coherently.
Furthermore, we show that, as the near-field enhancement increases,
the length scale over which it extends above and below the array becomes
larger and its spectral linewidth narrows. We also analyze the impact
that material losses have on these behaviors. As a direct application
of our results, we investigate the interaction between a nanoparticle
array and a dielectric slab placed a certain distance above it and
show that the extraordinary near-field enhancement produced by the
lattice resonance can lead to very strong interactions, even at significantly
large separations. This work provides a detailed characterization
of the limits of the near-field produced by lattice resonances and,
therefore, advances our knowledge of the optical response of periodic
arrays of nanostructures, which can be used to design and develop
applications exploiting the extraordinary properties of these systems.