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

Abstract

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 m which covers the spectral emission peak of an object maintained at ~300 K, and thus has potential applications in infrared camouflage.

In Situ Oxidizing Commercial Alloy to Achieve Selective Solar Absorption with High-Temperature Stability

“…In recent years, global climate change caused by carbon emissions from traditional fossil fuels has attracted widespread attention. Solar energy, as a renewable energy that is environmentally friendly and easy to obtain, has great application prospects. , The common way of utilizing solar energy is a concentrating solar power (CSP) system, which absorbs the sunlight through the absorber and converts solar radiation into thermal energy. , Then the thermal energy is used to heat the steam to drive a turbine and generate electricity. To improve the solar–thermal efficiency of the CSP system, the absorber should exhibit high absorptance in the solar band (0.3–2.5 μm) and low emittance in the mid-infrared band (3–20 μm). − …”

“…1,2 The common way of utilizing solar energy is a concentrating solar power (CSP) system, which absorbs the sunlight through the absorber and converts solar radiation into thermal energy. 3,4 Then the thermal energy is used to heat the steam to drive a turbine and generate electricity. To improve the solar−thermal efficiency of the CSP system, the absorber should exhibit high absorptance in the solar band (0.3−2.5 μm) and low emittance in the midinfrared band (3−20 μm).…”

Asymmetric Reflection Induced in Reciprocal Hyperbolic Materials

“…Controlling and modulating light propagation has long been a subject of intense interest, as it has enabled several key technological advances through the years. − More recently, considerable attention has been paid to the capability to select light propagating in a specific direction. − In particular, there has been tremendous interest in the type of propagation through some materials where light traveling forward shows a different behavior compared to when it is traveling backward. This “asymmetric” light propagation is the basis for a variety of optical technological applications; an example of this is signal-processing devices. , Nonreciprocal materials, such as magneto-optical materials and Weyl semimetals, have been investigated as a way to achieve asymmetric propagation of light because of their ability to break time-reversal symmetry. − For instance, the reflection of light has been successfully modulated using bulk magneto-optical materials, − as surface magnon-polaritons are highly nonreciprocal.…”