Coherent Control of Thermal Radiation with Nanophotonics

Incoherence of traditional thermal emission, such as blackbody radiation with broad bandwidth and omnidirectional nature, fundamentally restricts their practical applicability. Nanophotonic structures—particularly those engineered with subwavelength scale features—exhibit thermal radiation properties that markedly diverge from conventional emitters, enabling precise spectral and directional modulation of thermal emission. Herein, recent developments and challenges in the coherence control of thermal radiation with nanophotonics platforms are reviewed. First, the fundamental properties of thermal radiation and approaches for thermal radiation calculation are introduced. Also, recent developments of coherence control are presented, which are divided into three parts, including temporal coherence, spatial coherence, and polarization state of thermal radiation. As coherence control holds great potential for various infrared applications, the representative applications, such as infrared sensing, radiative cooling, thermal camouflage, and imaging, are subsequently introduced. Finally, a conclusion is made and the future developments of coherence control are prospected. By synthesizing current researches, this work highlights the transformative potential of coherent thermal radiation control and its impact on next-generation technologies, offering new perspectives in the areas of infrared thermal emission.