发表机构
California Institute of Technology; Resnick Sustainability Institute, California Institute of Technology; Department of Physics, Imperial College London（加州理工学院; 加州理工学院雷尼克可持续发展研究所; 伦敦帝国理工学院物理系）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
该研究设计了一种中红外双极化非互易吸收体，经实验验证可实现两种偏振下的非互易吸收，有望用于光子能量转换等领域。
AI 中文摘要
热辐射的发射和吸收通常通过基尔霍夫定律或互易性耦合，表现为光谱定向发射率与吸收率相等。近年来，磁光材料被认为是突破互易性约束的有前景途径，已有多项使用掺杂InAs的实验演示，但这些演示仅限于Voigt构型下的p偏振光，而黑体的热辐射是 unpolarized（非偏振）的。因此，为在两个偏振通道中均打破互易性，我们设计了一种工作在中红外光谱范围（11-20 μm）的纳米光子双极化非互易吸收体，其结构为掺杂InAs衬底上方的a-Si光子晶体平板，该衬底在施加磁场下具有反对称的非互易介电张量。该光子晶体平板支持与s偏振和p偏振光耦合的本征模式，产生的吸收峰对于前向和后向传播光向相反方向频移——这是平面亚波长系统中非互易性的特征。我们制备了该设计，然后使用磁场集成吸收率光谱测量其室温吸收率，实验证明了两种偏振下的非互易吸收。我们的设计是实现对光与热的完全控制的一步，有望改善光子能量转换、热管理以及中红外光隔离和循环。
英文摘要
The emission and absorption of thermal radiation are usually coupled via Kirchhoff's law or reciprocity, stated as the equality of spectral directional emissivity and absorptivity. Magneto-optical materials have recently been identified as a promising route to lifting the constraint of reciprocity, with multiple experimental demonstrations using doped InAs. However, these demonstrations have been limited to p-polarized light in the Voigt configuration, whereas thermal radiation from a blackbody is unpolarized. Therefore, to break reciprocity in both polarization channels, we design a nanophotonic, dual-polarized nonreciprocal absorber operating in the mid-infrared spectral range (11-20 $\unicode{x03BC}$m), consisting of an a-Si photonic crystal slab on top of a doped InAs substrate described by an antisymmetric, nonreciprocal dielectric tensor under an applied magnetic field. The photonic crystal slab supports eigenmodes that couple to both s- and p-polarized light, resulting in absorption peaks that frequency shift in opposite directions for forward- and backward-propagating light$\unicode{x2014}$a signature of nonreciprocity in planar, subwavelength systems. We fabricate our design, then measure its room-temperature absorptance using magnetic-field-integrated absorptance spectroscopy, experimentally demonstrating nonreciprocal absorption for both polarizations. Our design is a step toward the complete control of light as heat, which could improve photonic energy conversion, thermal management, and mid-infrared optical isolation and circulation.
Comments33 pages, 4 figures
