Nanophotonics Engineering Polarization Manipulation in Thermal Radiations: A Review

ABSTRACT The polarization manipulation (PoMa) of thermal radiation (ThRa) is critical for the development of technologies such as target detection, polarization imaging, and information encryption. The ThRa refers to the electromagnetic waves spontaneously emitted by objects with temperatures above absolute zero, originating from the thermal motion of charged particles. Traditional ThRa exhibits inherent characteristics, including broadband emission, nonpolarization, and incoherence. Over the past few decades, to achieve precise control over the ThRa's polarization properties, nanophotonic structures (such as metasurfaces and photonic crystals) have emerged as effective means to manipulate the ThRa at subwavelength scales, overcoming the limitations of conventional thermal emitters. The development of nanophotonic structures has also unlocked immense potential for compact, multifunctional, and reconfigurable ThRa's devices. Among various nanophotonic structures, anisotropic structures have demonstrated remarkable capabilities in manipulating the ThRa's polarization states. This capability has obtained widespread attention and has found broad applications in optical detection, imaging, and communication. This paper reviews recent advances and design principles of nanophotonic structures for the ThRa's PoMa, systematically organizing and analyzing key findings in this field to provide valuable references for researchers working on the ThRa's PoMa and its applications.