Van der Waals Materials for Applications in Nanophotonics
Van der Waals Materials for Applications in Nanophotonics
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DOI：
10.1002/lpor.202200957
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发表时间：
2022-08
影响因子：
11
通讯作者：
Panaiot G. Zotev;Yue Wang;D. Andres-Penares;Toby Severs‐Millard;S. Randerson;Xuerong Hu;Luca Sortino;Charalambos Louca;M. Brotons-Gisbert;T. Huq;S. Vezzoli;R. Sapienza;T. Krauss;B. Gerardot;A. Tartakovskii
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文献类型：
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作者：
Panaiot G. Zotev;Yue Wang;D. Andres-Penares;Toby Severs‐Millard;S. Randerson;Xuerong Hu;Luca Sortino;Charalambos Louca;M. Brotons-Gisbert;T. Huq;S. Vezzoli;R. Sapienza;T. Krauss;B. Gerardot;A. Tartakovskii
纳米光子结构使许多光学现象和应用成为可能。他们目前使用高折射率介质（如硅（Si）或磷化镓（GaP））制造，这对制造构成了限制，而金属依赖于等离子体，因此表现出高欧姆损耗，限制了可实现的应用。在这项工作中，一种新兴的层状，所谓的范德华（vdW）晶体被认为是一种可行的纳米光子学平台。提取了11个机械剥离薄膜（20-200 nm） vdW晶体的介电响应，揭示了高达n = 5的高折射率，高达Δn = 3的明显双折射，尖锐的吸收共振，以及从紫外到近红外的一系列透明窗口。利用vdW薄膜与各种衬底的兼容性，纳米天线随后在二氧化硅（SiO2）和金上制造。由于SiO2上的高折射率对比，可以观察到明显的Mie共振，从而导致强激子-光子耦合机制以及金上的高质量因子混合Mie -等离子体模式。通过堆叠扭曲晶体薄膜实现纳米天线，进一步证明了vdW材料在制造中的特定自由度，实现了非线性光学特性的控制，以及制造后的纳米结构转移，这对具有敏感材料的纳米光学非常重要。
Numerous optical phenomena and applications have been enabled by nanophotonic structures. Their current fabrication from high refractive index dielectrics, such as silicon (Si) or gallium phosphide (GaP), pose restricting fabrication challenges while metals, relying on plasmons and thus exhibiting high ohmic losses, limit the achievable applications. An emerging class of layered, so‐called van der Waals (vdW), crystals is presented as a viable nanophotonics platform in this work. The dielectric response of 11 mechanically exfoliated thin‐film (20–200 nm) vdW crystals is extracted, revealing high refractive indices up to n = 5, pronounced birefringence up to Δn = 3, sharp absorption resonances, and a range of transparency windows from ultraviolet to near‐infrared. Nanoantennas are subsequently fabricated on silicon dioxide (SiO2) and gold, utilizing the compatibility of vdW thin films with a variety of substrates. Pronounced Mie resonances are observed due to the high refractive index contrast on SiO2, leading to a strong exciton‐photon coupling regime as well as largely unexplored high‐quality‐factor, hybrid Mie‐plasmon modes on gold. Additional vdW‐material‐specific degrees of freedom in fabrication are further demonstrated by realizing nanoantennas from stacked twisted crystalline thin‐films, enabling control of nonlinear optical properties, and post‐fabrication nanostructure transfer, important for nano‐optics with sensitive materials.