True thermal antenna with hyperbolic metamaterials

TL;DR

This paper demonstrates that hyperbolic metamaterials can function as true thermal antennas, emitting highly directional infrared radiation with wavelength-independent emission angles, advancing thermal management technologies.

Contribution

It introduces hyperbolic materials with a wavelength-independent Brewster angle, enabling highly directional thermal emission akin to a true thermal antenna.

Findings

Hyperbolic materials exhibit a Brewster angle weakly dependent on wavelength.

These materials can radiate highly directional infrared heat flux.

Potential applications in advanced thermal management systems.

Abstract

A thermal antenna is an electromagnetic source which emits in its surrounding, a spatially coherent field in the infrared frequency range. Usually, its emission pattern changes with the wavelength so that the heat flux it radiates is weakly directive. Here, we show that a class of hyperbolic materials, possesses a Brewster angle which is weakly dependent on the wavelength, so that they can radiate like a true thermal antenna with a highly directional heat flux. The realization of these sources could open a new avenue in the field of thermal management in far-field regime.