posted on 2015-12-17, 01:41authored byChristopher L. Baldwin, Nicholas W. Bigelow, David J. Masiello
A consequence
of thermal diffusion is that heat, even when applied to a localized
region of space, has the tendency to produce a temperature change
that is spatially uniform throughout a material with a thermal conductivity
that is much larger than that of its environment. This implies that
the degree of spatial correlation between the heat power supplied
and the temperature change that it induces is likely to be small.
Here, we show, via theory and simulation, that through a Fano interference,
temperature changes can be both localized and controllably directed
within certain plasmon-supporting metal nanoparticle assemblies. This
occurs even when all particles are composed of the same material and
contained within the same diffraction-limited spot. These anomalous
thermal properties are compared and contrasted across three different
nanosystems, the coupled nanorod–antenna, the heterorod dimer,
and the nanocube on a substrate, known to support both spatial and
spectral Fano interferences. We conclude that the presence of a Fano
resonance is not sufficient by itself to induce a controllably nanolocalized
temperature change. However, when present in a nanosystem of the right
composition and morphology, temperature changes can be manipulated
with nanoscale precision, despite thermal diffusion.