Li Tengfei, Nagal Vivek, Gracias David H, Khurgin Jacob B
Opt Express. 2017 Jun 12;25(12):13588-13601. doi: 10.1364/OE.25.013588.
The multilayer hyperbolic metamaterials are known to be capable of imaging with sub-wavelength resolution. In this work performance of these "hyperbolic lenses" is analyzed in depth by employing commonly used transfer matrix method as well as the eigen-mode approach, the latter offering a clear physical insight into the operation of hyperbolic imagers and revealing their fundamental limitations. The resolution of multilayer structures is shown to decrease with the number of layers not only due to increased loss but also because of the severe suppression of large spatial frequencies caused by the cancellation between symmetric and antisymmetric eigen-modes. Additionally, the resolution is strongly affected by the granularity and fill ratio. In the end, hyperbolic metamaterials can create an image with subwavelength resolution only at very close distance to the object and hence limiting their utility.
多层双曲型超材料已知能够实现亚波长分辨率成像。在这项工作中，通过采用常用的传输矩阵法以及本征模方法，对这些“双曲型透镜”的性能进行了深入分析，后者能清晰地洞察双曲型成像仪的工作原理并揭示其基本局限性。多层结构的分辨率不仅会因损耗增加而随着层数的增加而降低，还会因为对称和反对称本征模之间的抵消导致大空间频率受到严重抑制。此外，分辨率还受到粒度和填充率的强烈影响。最后，双曲型超材料仅在非常靠近物体的距离处才能创建具有亚波长分辨率的图像，因此限制了它们的实用性。
