1. Multiple-resonant pad-rod nanoantennas for surface-enhanced infrared absorption spectroscopy
- Author
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Mingbo Pu, Vasyl G. Kravets, Zhirun Hu, Changtao Wang, Zeyu Zhao, and Weisheng Yue
- Subjects
Materials science ,Physics::Optics ,Infrared spectroscopy ,Bioengineering ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Electromagnetic radiation ,symbols.namesake ,National Graphene Institute ,General Materials Science ,Electrical and Electronic Engineering ,Spectroscopy ,Plasmon ,business.industry ,Mechanical Engineering ,General Chemistry ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,Wavelength ,Mechanics of Materials ,ResearchInstitutes_Networks_Beacons/national_graphene_institute ,symbols ,Optoelectronics ,Nanorod ,0210 nano-technology ,business ,Raman spectroscopy ,Refractive index - Abstract
Due to the ability to tightly confine electromagnetic energy, plasmonic nanoantennas have been widely studied for surface-enhanced infrared absorption (SEIRA) spectroscopy, surface-enhanced Raman spectroscopy as well as refractive index sensing. However, most of the nanoantennas are limited by narrow resonant band and it is rather challenging to detect multiple molecular fingerprints. In this work, we report dual and triple- resonant pad-rod plasmonic nanoantennas which are nanorods with large pads at their ends placed above gold (Au) mirror separated by a spacer layer. By adjusting the geometries, the nanoantennas have demonstrated dual and triple resonant bands enabling detection of molecular fingerprints at different wavelength. The calculated maximum SEIRA enhancement factor is around 1.8 × 106, which is among the highest reported so far. The pad-rod plasmonic nanoantennas have been used for the detection of molecules of polymethyl methacrylate (PMMA) by SEIRA and fingerprints of C=O and C–H bands are clearly identified. This work has shown that the multiple-resonant pad-rod plasmonic nanoantennas are promising for chemical and biomolecular sensing by the detection of vibrational fingerprints with SEIRA.
- Published
- 2019