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Split-Wedge Antennas with Sub-5 nm Gaps for Plasmonic Nanofocusing.
- Source :
-
Nano Letters . Dec2016, Vol. 16 Issue 12, p7849-7856. 8p. - Publication Year :
- 2016
-
Abstract
- We present a novel plasmonic antenna structure, a split-wedge antenna, created by splitting an ultrasharp metallic wedge with a nanogap perpendicular to its apex. The nanogap can tightly confine gap plasmons and boost the local optical field intensity in and around these opposing metallic wedge tips. This three-dimensional split-wedge antenna integrates the key features of nanogaps and sharp tips, i.e., tight field confinement and three-dimensional nanofocusing, respectively, into a single platform. We fabricate split-wedge antennas with gaps that are as small as 1 nm in width at the wafer scale by combining silicon V-grooves with template stripping and atomic layer lithography. Computer simulations show that the field enhancement and confinement are stronger at the tip-gap interface compared to what standalone tips or nanogaps produce, with electric field amplitude enhancement factors exceeding 50 when near-infrared light is focused on the tip-gap geometry. The resulting nanometric hotspot volume is on the order of λ3/106. Experimentally, Raman enhancement factors exceeding 107 are observed from a 2 nm gap split-wedge antenna, demonstrating its potential for sensing and spectroscopy applications. [ABSTRACT FROM AUTHOR]
- Subjects :
- *PLASMONICS
*PLASMONS (Physics)
*ANTENNA arrays
*RAMAN effect
*SILICON
Subjects
Details
- Language :
- English
- ISSN :
- 15306984
- Volume :
- 16
- Issue :
- 12
- Database :
- Academic Search Index
- Journal :
- Nano Letters
- Publication Type :
- Academic Journal
- Accession number :
- 120478067
- Full Text :
- https://doi.org/10.1021/acs.nanolett.6b04113