Department of Electrical Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States.
ACS Nano. 2011 Jun 28;5(6):4641-7. doi: 10.1021/nn2004603. Epub 2011 Apr 18.
Metamaterials offer a new approach to create surface coatings with highly customizable electromagnetic absorption from the microwave to the optical regimes. Thus far, efficient metamaterial absorbers have been demonstrated at microwave frequencies, with recent efforts aimed at much shorter terahertz and infrared wavelengths. The present infrared absorbers have been constructed from arrays of nanoscale metal resonators with simple circular or cross-shaped geometries, which provide a single band response. In this paper, we demonstrate a conformal metamaterial absorber with a narrow band, polarization-independent absorptivity of >90% over a wide ±50° angular range centered at mid-infrared wavelengths of 3.3 and 3.9 μm. The highly efficient dual-band metamaterial was realized by using a genetic algorithm to identify an array of H-shaped nanoresonators with an effective electric and magnetic response that maximizes absorption in each wavelength band when patterned on a flexible Kapton and Au thin film substrate stack. This conformal metamaterial absorber maintains its absorption properties when integrated onto curved surfaces of arbitrary materials, making it attractive for advanced coatings that suppress the infrared reflection from the protected surface.
超材料提供了一种新方法来创建具有高度可定制的电磁吸收表面涂层，从微波到光学波段都可以实现。到目前为止，高效的超材料吸收体已经在微波频率下得到了证明，最近的研究工作旨在实现更短的太赫兹和红外波长。目前的红外吸收体是由具有简单圆形或十字形几何形状的纳米级金属谐振器阵列构成的，这些结构提供了单一的带宽响应。在本文中，我们展示了一种共形超材料吸收体，它在宽 ±50°角范围内具有窄带、偏振无关的吸收率 >90%，中心波长在中红外波长 3.3 和 3.9 μm 处。通过使用遗传算法来识别具有有效电和磁响应的 H 形纳米谐振器阵列，在柔性 Kapton 和 Au 薄膜基底堆叠上进行图案化，实现了高效的双频超材料。这种共形超材料吸收体在集成到任意材料的曲面上时保持其吸收特性，这使得它成为抑制受保护表面红外反射的先进涂层的理想选择。
