Tunable multiband metasurfaces by moiré nanosphere lithography. Issue 48 (6th October 2015)

• Record Type: Journal Article
• Authors: Wu, Zilong; Chen, Kai; Menz, Ryan; Nagao, Tadaaki; Zheng, Yuebing
• Is Part Of: Nanoscale. Volume 7:Issue 48(2015)
• Page Start: 20391
• Page End: 20396
• Publication Date: 2015-10-06
• Subjects: Nanoscience -- Periodicals; Nanotechnology -- Periodicals; 620.505
• DOI: 10.1039/c5nr05645d
• Languages: English
• ISSNs: 2040-3364

Abstract

Abstract : Single moiré metasurfaces support multiple surface plasmon modes with a wide range of resonant wavelengths from visible to near-infrared to mid-infrared regimes. Abstract : Moiré nanosphere lithography (MNSL), which features the relative in-plane rotation between two layers of self-assembled monodisperse nanospheres as masks, provides a cost-effective approach for creating moiré patterns on generic substrates. In this work, we experimentally and numerically investigate a series of moiré metasurfaces by MNSL. Due to the variety of gradient plasmonic nanostructures in arrays, single moiré metasurfaces can support multiple localized surface plasmon (LSP) modes with a wide range of resonant wavelengths from ∼600 nm to ∼4200 nm. We analyze the origin of the LSP modes based on the optical spectra and near-field electromagnetic distributions. In addition, we fabricate and analyze the metasurfaces with high-density nanogap structures. These nanogap structures support plasmonic gap modes with significant field enhancements. With their tunable multiband optical responses from visible to near-infrared to mid-infrared regimes, these moiré metasurfaces are applicable for ultrabroadband absorbers, multiband surface-enhanced infrared and Raman spectroscopy, and broadband single-molecule spectroscopy.