Abstract Multilayers with metal-dielectric stacks are considered as an effective approach to produce hyperbolic metamaterials (HMMs). However, fabricating ultrathin metal layers with high crystallinity for low-loss HMMs is very challenging. In this work, TiN has been applied as an alternative candidate to the noble metals, and TiN/MgO multilayers with varied numbers of layers and layer thicknesses have been designed. The microstructure study reveals that the thickness of TiN nanolayer is controlled as thin as 2.9 nm, 1.26 nm and 0.9 nm by varying the total number of layers, and the epitaxial quality of the multilayer films is high even with such ultrathin layers. Extraordinary optical properties have been achieved, such as plasmonic resonance in visible range, as well as strong optical anisotropy. In addition, the real part of dielectric permittivity ( e ′ ) shows opposite optical anisotropy in different wavelength ranges, i.e. e ∥ ′ >0, e ⊥ ′ e ∥ ′ e ⊥ ′ >0 under higher wavelength, which is a novel property realized in a multilayer system.

中文翻译：

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外延 TiN/MgO 多层与超薄 TiN 和 MgO 层作为可见区双曲超材料

摘要 具有金属-电介质堆叠的多层被认为是生产双曲超材料 (HMM) 的有效方法。然而，为低损耗 HMM 制造具有高结晶度的超薄金属层非常具有挑战性。在这项工作中，TiN 已被用作贵金属的替代候选物，并设计了具有不同层数和层厚的 TiN/MgO 多层膜。微观结构研究表明，通过改变总层数，可以将 TiN 纳米层的厚度控制为 2.9 nm、1.26 nm 和 0.9 nm，并且即使具有这种超薄层，多层膜的外延质量也很高。已经实现了非凡的光学特性，例如可见光范围内的等离子体共振，以及强大的光学各向异性。此外，