为了满足红外探测器件集成化和对红外宽光谱范围吸收的需求, 设计了一种工作在长波红外波段(8~14 μm)的超宽带、高吸收、极化不敏感的超材料吸收器。通过在金属-介质-金属三层异质的超材料吸收器结构的顶部金属周围镶嵌一层介质形成超表面, 以增加谐振强度和吸收带宽。在8~13.6 μm的带宽范围内, 该结构有超过90%的平均吸收率, 覆盖了大部分长波红外大气窗口波段, 对红外探测领域有着重要意义。研究结果表明: 镶嵌的金属-介质组成的介质波导模式和谐振腔模式的结合以及传播型表面等离激元模式的激发是形成宽带高吸收的主要原因, 并且谐振模式的谐振波长可以通过相关参数来进行调控。本文的研究结果为可调谐宽带长波红外吸收材料的设计提供参考, 该设计方法可推广到中波红外波段、甚至长波红外或其它波段。

In order to meet the requirements of integration of infrared devices and the wideband absorption of infrared light, a novel ultra-broadband, high-absorbance and polarization-independent metamaterial absorber working in the long-wave infrared region (8~14 μm) is designed.By inserting a dielectric layer around the top metal of a metal-dielectric-metal metamaterial absorber to form a metasurface, the resonance intensity and absorption bandwidth can be improved.The structure has an average absorptivity greater than 90% in the range of 8.0 μm to 13.6 μm, covering most of the long-wave infrared atmospheric window bands, which is of great significance to infrared devices. The results indicate that the excitation of Propagating Surface Plasmon (PSP) modes and embedded cavity modes generated by the combination of dielectric-loaded surface plasmon polaritons waveguide and cavity modes contribute to broadband absorption.Moreover, the resonant wavelength of the resonance mode can be tuned by relevant parameters.The results of this paper provide a reference for the design of tunable broadband long-wavelength infrared(LWIR) absorbers. It is suggested that this design method can be extended to the medium wavelength infrared band, the very long-wavelength infrared band and others.