Kilic Ufuk, Hilfiker Matthew, Wimer Shawn, Ruder Alexander, Schubert Eva, Schubert Mathias, Argyropoulos Christos
Department of Electrical and Computer Engineering, University of Nebraska-Lincoln, Lincoln, NE, 68588, USA.
Onto Innovation Inc., Wilmington, MA, 01887, USA.
Nat Commun. 2024 May 4;15(1):3757. doi: 10.1038/s41467-024-48051-4.
The inherently weak chiroptical responses of natural materials limit their usage for controlling and enhancing chiral light-matter interactions. Recently, several nanostructures with subwavelength scale dimensions were demonstrated, mainly due to the advent of nanofabrication technologies, as a potential alternative to efficiently enhance chirality. However, the intrinsic lossy nature of metals and the inherent narrowband response of dielectric planar thin films or metasurface structures pose severe limitations toward the practical realization of broadband and tailorable chiral systems. Here, we tackle these problems by designing all-dielectric silicon-based L-shaped optical metamaterials based on tilted nanopillars that exhibit broadband and enhanced chiroptical response in transmission operation. We use an emerging bottom-up fabrication approach, named glancing angle deposition, to assemble these dielectric metamaterials on a wafer scale. The reported strong chirality and optical anisotropic properties are controllable in terms of both amplitude and operating frequency by simply varying the shape and dimensions of the nanopillars. The presented nanostructures can be used in a plethora of emerging nanophotonic applications, such as chiral sensors, polarization filters, and spin-locked nanowaveguides.
天然材料固有的弱手性光学响应限制了它们在控制和增强手性光与物质相互作用方面的应用。最近，由于纳米制造技术的出现，展示了几种具有亚波长尺度尺寸的纳米结构，作为有效增强手性的潜在替代方案。然而，金属固有的损耗特性以及介电平面薄膜或超表面结构固有的窄带响应，对宽带和可定制手性系统的实际实现构成了严重限制。在此，我们通过设计基于倾斜纳米柱的全介电硅基L形光学超材料来解决这些问题，该超材料在透射操作中表现出宽带和增强的手性光学响应。我们使用一种新兴的自下而上的制造方法，即掠角沉积，在晶圆尺度上组装这些介电超材料。通过简单地改变纳米柱的形状和尺寸，所报道的强手性和光学各向异性特性在幅度和工作频率方面都是可控的。所展示的纳米结构可用于众多新兴的纳米光子应用，如手性传感器、偏振滤波器和自旋锁定纳米波导。
