Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, P. R. China.
Nanoscale. 2015 Oct 28;7(40):16798-804. doi: 10.1039/c5nr03391h. Epub 2015 Sep 24.
We demonstrate that the silver nanoplate-based macroscopically periodic (macro-periodic) and microscopically random (micro-random) structure has a broadband near-field enhancement as compared to conventional silver gratings. The specific field enhancement in a wide spectral range (from UV to near-infrared) originates from the abundance of localized surface-plasmonic (LSP) modes in the microscopically random distributed silver nanoplates and propagating Bloch-plasmonic (PBP) modes from the macroscopically periodic pattern. The characterization of polarization dependent spectral absorption, surface-enhanced Raman spectroscopy (SERS), as well as theoretical simulation was conducted to comprehensively understand the features of the broadband spectrum and highly concentrated near-field. The reported macro-periodic and micro-random structure may offer a new route for the design of plasmonic systems for photonic and optoelectronic applications.
我们证明，与传统的银光栅相比，基于银纳米板的宏观周期性（宏观周期性）和微观随机性（微观随机性）结构具有宽带近场增强。在宽光谱范围（从紫外到近红外）内的特定场增强源于微观随机分布的银纳米板中的局域表面等离子体（LSP）模式的丰富性和宏观周期性模式中的传播布洛赫等离子体（PBP）模式。通过进行偏振相关光谱吸收、表面增强拉曼光谱（SERS）以及理论模拟的表征，全面了解宽带光谱和高度集中近场的特性。所报道的宏观周期性和微观随机性结构可为光子和光电应用的等离子体系统设计提供新途径。
