Optimization Design of a Multilayer Structure for Broadband and Direction-Selective Emissivity

Micro-nano structures for broadband and direction-selective emission have long been a scientific and engineering challenge. In this work, based on the emissivity distribution of three silver-coated dielectric media, including silicon dioxide (SiO₂), silicon monoxide (SiO), and aluminum oxide (Al₂O₃), a multilayer structure was designed for broadband and direction-selective emissivity. The structure's emissivity varying with wavelength and emission direction was analyzed. Effects of different arrangement modes of the dielectric media and the thickness of each dielectric layer on the multilayer structure's emissivity were examined for design optimization. The optimal multilayer structure exhibits a strong direction-selective emissivity within a broadband wavelength of 8.0-11.0 pm which covers the spectral emission peak of an object maintained at ~300 K, and thus has potential applications in infrared camouflage.