Observation of Janus Chirality for Coherent Thermal Emission from Metasurfaces

TL;DR

This paper reports the experimental demonstration of Janus chiral thermal emission from metasurfaces, enabling control over circular polarization states of thermal radiation with potential applications in spin-controlled light-matter interactions.

Contribution

It introduces a novel metasurface design supporting Janus chiral thermal emission with opposite circular handednesses on either side, validated by coupled-mode theory.

Findings

Experimental confirmation of Janus chiral thermal emission.

High-Q resonances enable near-unity circular dichroism.

Flatband metasurfaces facilitate spin-controlled thermal radiation.

Abstract

Metasurfaces emerged as a powerful tool for controlling thermal radiation, yet achieving coherent emission with opposite circular handednesses remains a highly challenging problem. Here, we demonstrate experimentally the Janus chiral thermal emission from metasurfaces with opposite circular handednesses on either side of a single device. We employ anisotropic metasurfaces supporting high-Q resonances with photonic flatbands enabling near-unity circular dichroism through in-plane symmetry control. Our experiments confirm the Janus coherent emission, and they are validated by the results of the coupled-mode theory. The flatband resonant metasurfaces enabling a control of chiral thermal emission provide an efficient platform for spin-controlled light-matter interaction.