Thermal non-equilibrium process for nonreciprocity with dual-TE/single-TM peaks

Abstract

In this study, we present a nonreciprocal thermal emitter with dual-polarization capabilities, utilizing a monolayer silicon ring array featuring circular voids. The device demonstrates nonreciprocal behavior under both transverse electric (TE) and transverse magnetic (TM) polarizations, displaying two distinct nonreciprocal peaks in TE polarization and a single peak in TM polarization. Rigorous coupled-wave analysis (RCWA) and validation through coupled-mode theory (CMT) confirm high nonreciprocal efficiency in the mid-infrared region. Specifically, under TE polarization, the two nonreciprocal peaks are observed at wavelengths of 15.074 μm and 15.228 μm, yielding nonreciprocal efficiencies of 94.48 % and 95.65 %, respectively. Under TM polarization, the nonreciprocal peak is positioned at 15.127 μm, with an efficiency of 94.58 %. Allowing for functional differentiation based on the polarization of the incident light. This dual-polarization feature significantly broadens its application potential in thermal management, energy harvesting, and infrared camouflage, particularly enabling more efficient energy conversion and radiation control at small incident angles. Our work offers new insights for future multifunctional nonreciprocal thermal emitters.