Resonant-cavity enhanced thermal emission

Abstract

In this paper we present a vertical-cavity enhanced resonant thermal emitter-a highly directional, narrowband, tunable, partially coherent thermal source. This device enhances thermal emittance of a metallic or any other highly reflective structure to unity near a cavity resonant frequency. The structure consists of a planar metallic surface ͑e.g., silver, tungsten͒, a dielectric layer on top of the metal that forms a vertical cavity, followed by a multilayer dielectric stack acting as a partially transparent cavity mirror. The resonant frequency can easily be tuned by changing the cavity thickness ͑thus shifting resonant emission peak͒, while the angle at which the maximum emittance appears can be tuned as well by changing the number of dielectric stack layers. The thermal emission exhibits an extremely narrow angular emission lobe, suggesting increased spatial coherence. Furthermore, we show that we can enhance the thermal emission of an arbitrarily low-emittance material, choosing a properly designed thermal cavity, to near unity.

Tailor the Functionalities of Metasurfaces Based on a Complete Phase Diagram

“…where a  and r  are two parameters denoting the life times of the excited resonance due to absorption inside the structure and radiation to the far field, [29,30]), the absorbance decreases significantly as leaving this phase boundary ( Fig. 1(c)).…”

Analog of superradiant emission in thermal emitters

“…From a fundamental physics perspective, with the capability to tailor lightmatter interactions, nanophotonic structures can enable thermal emission behaviors that are drastically different from those of conventional bulk emitters [12][13][14][15][16][17][18][19][20][21][22][23]. For example, while blackbody emitters are typically considered to be incoherent with a total emission power limited by the Stephan-Boltzman law, nanophotonic emitters can be highly coherent [6,20,22] or have emission beyond the blackbody limit [4,19].…”

Enhancing far-field thermal emission with thermal extraction

“…Any actual macroscopic thermal body cannot emit more thermal radiation than a blackbody. The Stefan-Boltzman law provides an important theoretical foundation for much of the recent works aiming to design nanophotonic structures in order to tailor the spatial and spectral properties of far-field thermal emission [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] .…”