48,291 research outputs found
Near-field refrigeration and tunable heat exchange through four-wave mixing
We modify and extend a recently proposed four-wave mixing scheme [Opt.
Express 25 (19),23164 (2017)] for achieving near-field thermal upconversion and
energy transfer, to demonstrate efficient thermal refrigeration at low
intensities W/m over a wide range of gap sizes (from tens to
hundreds of nanometers) and operational temperatures (from tens to hundreds of
Kelvins). We further exploit the scheme to achieve magnitude and directional
tunability of near-field heat exchange between bodies held at different
temperatures
Temperature control of thermal radiation from heterogeneous bodies
We demonstrate that recent advances in nanoscale thermal transport and
temperature manipulation can be brought to bear on the problem of tailoring
thermal radiation from compact emitters. We show that wavelength-scale
composite bodies involving complicated arrangements of phase-change
chalcogenide (GST) glasses and metals or semiconductors can exhibit large
emissivities and partial directivities at mid-infrared wavelengths, a
consequence of temperature localization within the GST. We consider multiple
object topologies, including spherical, cylindrical, and mushroom-like
composites, and show that partial directivity follows from a complicated
interplay between particle shape, material dispersion, and temperature
localization. Our calculations exploit a recently developed fluctuating-volume
current formulation of electromagnetic fluctuations that rigorously captures
radiation phenomena in structures with both temperature and dielectric
inhomogeneities.Comment: 17 pages, 7 figuer
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