Li Jiayu, Li Zhuo, Shen Sheng
Opt Express. 2020 Nov 9;28(23):34123-34136. doi: 10.1364/OE.405308.
Near-field radiation can exceed the blackbody radiation limit due to the contributions from evanescent waves. One promising approach to further enhance near-field radiation beyond existing bulk materials is to utilize metamaterials or metasurfaces made from subwavelength plasmonic structures. In this work, we investigate the near-field thermal radiation between complex plasmonic structures with higher-order symmetry and degeneracy, which is crucial for understanding the radiative heat exchange between metamaterials or metasurfaces at extremely small gaps. We demonstrate that the introduction of degeneracy can drastically boost near-field thermal radiation between plasmonic structures. The enhancement of near-field thermal radiation originates from the emergence of degenerate resonance modes and the secondary emission of thermal photons due to the nonzero coupling between the degenerate modes. Our study provides new pathways for designing high-intensity near-field thermal emitters and absorbers for thermophotovoltaics, thermal management, and infrared spectroscopy.
由于倏逝波的贡献，近场辐射可以超过黑体辐射极限。一种比现有块体材料进一步增强近场辐射的有前景的方法是利用由亚波长等离子体结构制成的超材料或超表面。在这项工作中，我们研究了具有高阶对称性和简并性的复杂等离子体结构之间的近场热辐射，这对于理解超材料或超表面在极小间隙处的辐射热交换至关重要。我们证明简并性的引入可以显著提高等离子体结构之间的近场热辐射。近场热辐射的增强源于简并共振模式的出现以及由于简并模式之间的非零耦合导致的热光子二次发射。我们的研究为设计用于热光伏、热管理和红外光谱的高强度近场热发射器和吸收器提供了新途径。
