Thermal antenna behavior for thin films structures

TL;DR

This paper demonstrates that thin film structures can act as directional thermal emitters over broad spectral bands due to mode quantization, offering a new physical principle for thermal radiation control.

Contribution

It introduces a novel physical mechanism for directional thermal emission in thin films, distinct from grating-based methods, supported by theoretical analysis.

Findings

Thin films can emit radiation directionally over broad spectral bands.

Mode quantization in thin films enables controlled thermal emission.

The effect is comparable to grating-based emitters but based on different physics.

Abstract

We show that under proper conditions thin films structures behave like thermal sources that are able to emit radiation in well defined directions over a broad spectral band for both polarization states of light. This effect results from the quantization of modes inside the structure as in a Fabry-Perot resonator. A theoretical demonstration of this effect is given using the matrix transfer method. This result is similar to the best efficient reported results with gratings but using a completely different physical principle [J. J. Greffet et al., Nature 416, 61 (2002)].