A geometric Doppler effect manifested by a spin-split dispersion relation of thermal radiation is observed. A spin-dependent dispersion splitting was obtained in a structure consisting of a coupled thermal antenna array. The effect is due to a spin-orbit interaction resulting from the dynamics of the surface waves propagating along the structure whose local anisotropy axis is rotated in space. The observation of the spin-symmetry breaking in thermal radiation may be utilized for manipulation of spontaneous or stimulated emission.

No abstract

Observation of a spin degeneracy breaking in thermal radiation emitted from an inhomogeneous anisotropic lattice composed of coupled antennas supporting surface waves is presented. The spin degeneracy removal is manifested by a spin-dependent momentum splitting of the radiative mode which resembles the Rashba effect. The spin split dispersion arises from the inversion asymmetry of the lattice. Our experiment confirms that the spatial rate of the inhomogeneity determines the degree of the spin- dependent momentum redirection. The influence of the inversion asymmetry on the dispersion was studied by comparing the results to those produced by homogeneous lattices and characterizing the behavior of the isolated thermal antennas.

In high temperature and vacuum applications, for which heat transfer is predominantly by radiation, the material’s surface texture is of substantial importance. Several micro and nanostructures designs have been proposed to enhance a material’s emissivity and its radiative coherence. Control of thermal emission is of crucial concern in the design of infrared sources, in electronic chip coolants, in high-efficiency photovoltaic cells, and in solar energy conversion. In this review paper, we present microscale and nanoscale structures supporting surface waves for obtaining polarization manipulation of thermal emission, extraordinary coherent thermal radiation, bandgap in the spectral emission, spin symmetry breaking of coupled thermal antenna array, and a broadband infrared absorption.

No abstract