Quasi-coherent thermal emitter based on refractory plasmonic materials

TL;DR

This paper demonstrates a refractory plasmonic titanium nitride grating that efficiently emits collimated, quasi-monochromatic mid-infrared radiation at high temperature, with potential applications in thermal photonics.

Contribution

It introduces a refractory plasmonic grating that achieves high-brightness, collimated thermal emission in the mid-infrared, validated by experimental and numerical analysis.

Findings

Achieved a spatial coherence length of 32λ.

Emitted radiation centered around 3 μm with 70 nm bandwidth.

Demonstrated good agreement between experiment and numerical model.

Abstract

The thermal emission of refractory plasmonic metamaterial - a titanium nitride 1D grating - is studied at high operating temperature (540 {\deg}C). By choosing a refractory material, we fabricate thermal gratings with high brightness that are emitting mid-infrared radiation centered around 3 $\mu$m. We demonstrate experimentally that the thermal excitation of plasmon-polariton on the surface of the grating produces a well-collimated beam with a spatial coherence length of 32{\lambda} (angular divergence of 1.8{\deg}) which is quasi-monochromatic with a full width at half maximum of 70 nm. These experimental results show good agreement with a numerical model based on a two-dimensional full-wave analysis in frequency domain.