Temperature control of thermal radiation from composite bodies

Abstract

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 midinfrared 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.

Radiative heat transfer in many-body systems: Coupled electric and magnetic dipole approach

“…Over the past few years, many theoretical approaches on NFRHT problems have been put forward by combining the Maxwell electromagnetic theory and the fluctuation-dissipation theorem [3]. These approaches, including the Green's function [3,[19][20][21], the scattering matrix [22][23][24][25][26], the finite difference time domain [27][28][29][30][31], the thermal discrete dipole approximation [32][33][34], the rigorous coupled wave analysis [35][36][37][38],the fluctuating surface [39][40][41] and volume [42][43][44] current etc., greatly enrich our understanding of NFRHT problems. Meanwhile, more and more experimental researches on NFRHT have been performed [45][46][47][48][49][50][51][52][53].…”

Circularly Polarized Thermal Radiation From Nonequilibrium Coupled Antennas

“…Our work suggests the possibility of exploring such phenomena using thermal nonequilibrium without applying magnetic field. In context of using nonequilibrium systems for shaping thermal radiation, other recent works have explored directional emissivity [33,34], nontrivial thermal forces and torques [35] and enhanced emissivity from nonequilibrium antennas [36]. Our work conveys that one can take advantage of temperature-based reconfigurability in nonequilibrium systems, for numerous applications in communications, sensing and detection technologies.…”

General formulation of coupled radiative and conductive heat transfer between compact bodies

“…On the other hand, while it is known that conduction has a strong influence on RHT experiments [26], the converse has thus far been largely unexplored because RHT is typically too small to result in appreciable temperature gradients [27][28][29][30]. However, our recent work [6] suggests that such an interplay can be significant at tens of nanometer separations and may already be present (though overlooked) in recent experiments [31][32][33][34].…”

“…In the following, we take AZO as an illustrative example and assume a temperature-independent dielectric constant to illustrate the main effects stemming from CR coupling, leaving a full description, which is more relevant in the presence of large temperature gradients, to future work. Note that we recently considered the full temperature-dependent dielectric response in the context of far-field emission [46,47], which can also be handled by the FVC framework. To begin with, we show that even in the absence of CR interplay, the RHT spectrum and spatial distribution inside the nanorods differs significantly from those of AZO slabs of the same thickness.…”