Hollow nanocone array (HNCA) films (cm × cm), composed of two Ag and Au nanoshells, are fabricated via a low-cost and efficient colloidal lithography technique. The relative position of the Ag and Au nanoshells can be controlled to generate various chiral asymmetries. A pronounced chiroptical response is observed in the ultraviolet–visible region with the anisotropy factor up to 10^–1, which is rooted in the asymmetric current oscillations and electric field distributions. Beyond previous reports on plasmonic chiral metamaterials, the HNCA can be free-standing and further transferred to other functional and flexible substrates, such as polydimethylsiloxane (PDMS), highly curved surfaces, prepatterned films, and hydrogels, while keeping the original features. The good transferability would make HNCA more flexible in specific applications. Furthermore, the chiral HNCAs offer a series of chiral resonance cavities, which are conducive for the research of chiral sensing, confinement, chiral signal transmission, and amplification. Overall, this work provides a scalable metamaterial to tune the plasmonic chiral response, and HNCA would be a promising candidate of the components in chiral optical devices and sensors.

中文翻译：

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具有3D谐振腔的自由等离子体等离子手性超材料

空心纳米锥阵列（HNCA）膜（cm×cm）由两个Ag和Au纳米壳组成，是通过低成本高效的胶体光刻技术制成的。可以控制Ag和Au纳米壳的相对位置以产生各种手性不对称性。在紫外线可见区域观察到明显的脊骨反应，各向异性系数高达10 ^–1，其根源在于不对称的电流振荡和电场分布。除了以前关于等离子手性超材料的报道，HNCA可以独立放置并进一步转移到其他功能性和柔性基材上，例如聚二甲基硅氧烷（PDMS），高度弯曲的表面，预制膜和水凝胶，同时保持原始功能。良好的可移植性将使HNCA在特定应用中更加灵活。此外，手性HNCA提供了一系列手性共振腔，有利于手性传感，封闭，手性信号传递和扩增的研究。总的来说，这项工作提供了可扩展的超材料来调节等离子体手性响应，HNCA将成为手性光学设备和传感器中组件的有前途的候选者。