Infrared metamaterial absorber (MMA) based on metal-insulator-metal (MIM) configuration with flexible design, perfect and selective absorption, has attracted much attention recently for passive radiative cooling applications. To cool objects passively, broadband infrared absorption (i.e. 8–14 μm) is desirable to emit thermal energy through atmosphere window. We present a novel MMA composed of multilayer MIM resonators periodically arranged on a PbTe/MgF₂ bilayer substrate. Verified by the rigorous coupled-wave analysis method, the proposed MMA shows a relative bandwidth of about 45% (from 8.3 to 13.1 μm with the absorption intensity over 0.8). The broadband absorption performs stably over a wide incident angle range (below 50) and predicts 12 K cooling below ambient temperature at nighttime. Compared with the previous passive radiative coolers, our design gets rid of the continuous metal substrate and provides an almost ideal transparency window (close to 100%) for millimeter waves over 1 mm. The structure is expected to have potential applications in thermal control of integrated devices, where millimeter wave signal compatibility is also required.

基于金属-绝缘体-金属 (MIM) 配置的红外超材料吸收器 (MMA) 具有灵活的设计、完美的选择性吸收，最近在被动辐射冷却应用中备受关注。为了被动地冷却物体，宽带红外吸收（即 8-14 μm）需要通过大气窗口发射热能。我们提出了一种新型 MMA，由周期性排列在 PbTe/MgF ₂上的多层 MIM 谐振器组成双层基板。通过严格的耦合波分析方法验证，所提出的 MMA 显示出约 45% 的相对带宽（从 8.3 到 13.1 μm，吸收强度超过 0.8）。宽带吸收在较宽的入射角范围内（低于 50 度）稳定运行，并预测夜间温度低于环境温度 12 K。与之前的无源辐射冷却器相比，我们的设计摆脱了连续金属基板，为超过 1 毫米的毫米波提供了几乎理想的透明度窗口（接近 100%）。该结构有望在集成设备的热控制中具有潜在应用，其中还需要毫米波信号兼容性。