Baranov Denis G, Xiao Yuzhe, Nechepurenko Igor A, Krasnok Alex, Alù Andrea, Kats Mikhail A
Department of Physics, Chalmers University of Technology, Gothenburg, Sweden.
Department of Electrical and Computer Engineering, University of Wisconsin-Madison, Madison, WI, USA.
Nat Mater. 2019 Sep;18(9):920-930. doi: 10.1038/s41563-019-0363-y. Epub 2019 May 27.
Thermal emission is a ubiquitous and fundamental process by which all objects at non-zero temperatures radiate electromagnetic energy. This process is often assumed to be incoherent in both space and time, resulting in broadband, omnidirectional light emission toward the far field, with a spectral density related to the emitter temperature by Planck's law. Over the past two decades, there has been considerable progress in engineering the spectrum, directionality, polarization and temporal response of thermally emitted light using nanostructured materials. This Review summarizes the basic physics of thermal emission, lays out various nanophotonic approaches to engineer thermal emission in the far field, and highlights several applications, including energy harvesting, lighting and radiative cooling.
热发射是一种普遍存在的基本过程，所有非零温度的物体都会通过该过程辐射电磁能量。通常认为这个过程在空间和时间上都是非相干的，会向远场产生宽带、全向的光发射，其光谱密度由普朗克定律与发射体温度相关。在过去二十年中，利用纳米结构材料在调控热发射光的光谱、方向性、偏振和时间响应方面取得了显著进展。本综述总结了热发射的基本物理原理，阐述了在远场调控热发射的各种纳米光子学方法，并重点介绍了包括能量收集、照明和辐射冷却在内的几种应用。
