Photonics Research, Vol. 8, Issue 12, 12001850 (2020)
Boosting a sub-10 nm nanogap array by plasmon-triggered waveguide resonance
Yu Tian1, Hailong Wang1, Yijia Geng2, Lili Cong1, Yu Liu2, Weiqing Xu1, and Shuping Xu1,*
- 1State Key Laboratory of Supramolecular Structure and Materials, Institute of Theoretical Chemistry, College of Chemistry, Jilin University, Changchun 130012, China
- 2State Key Laboratory of Applied Optics, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, China
Gap-type metallic nanostructures are widely used in catalytic reactions, sensors, and photonics because the hotspot effect on these nanostructures supports giant local electromagnetic field enhancement. To achieve hotspots, researchers devote themselves to reducing gap distances, even to 1 nm. However, current techniques to fabricate such narrow gaps in large areas are still challenging. Herein, a new coupling way to boost the sub-10 nm plasmonic nanogap array is developed, based on the plasmon-triggered optical waveguide resonance via near-field coupling. This effect leads to an amplified local electromagnetic field within the gap regions equivalent to narrower gaps, which is evidenced experimentally by the surface-enhanced Raman scattering intensity of probed molecules located in the gap and the finite-difference time-domain numerical simulation results. This study provides a universal strategy to promote the performance of the existing hotspot configurations without changing their geometries.
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