Spectroscopic study of gap-surface plasmons in a metallic convex groove array and their applications in nanofocusing and plasmonic sensing
Spectroscopic study of gap-surface plasmons in a metallic convex groove array and their applications in nanofocusing and plasmonic sensing
Plasmonic tapered grooves have been proven to be good candidates for the excitation of gap surface plasmons (GSPs), surface plasmons trapped vertically inside a metallic tapered groove or slit. GSPs have attracted tremendous interest due to their unique properties of concentrating light in nanosized gaps with significant field enhancement, thus offering potential applications such as ultracompact nanocircuits, broadband light absorbers, and plasmonic sensors. In this paper, we focus on GSPs supported by periodic arrays of narrow convex grooves and study in detail their properties by using visible-near-infrared (VIS-NIR) spectroscopy. We identify strong second- and third-order GSP modes excited in ultrasharp convex grooves. The dependence of GSP resonances on the groove profile is analyzed with the help of detailed full-wave simulations, revealing the fact that an ultrasharp, but finite, gap exists at the groove bottom and plays a crucial role in determining both the GSP resonance positions and the nanofocusing capability with much improved field enhancement inside the grooves. Spectral shifts of the observed GSP resonances relative to the simulation results are found in a shorter wavelength range and are qualitatively explained as nonlocal effects originating from the nonclassical microscopic behavior of local currents and charges at imperfect interfaces. Utilizing such strong and distinguishable GSP resonance line shapes in an otherwise flat reflectivity spectral baseline, we experimentally demonstrate the capability of convex groove arrays to perform dual-band refractive index sensing in the VIS-NIR range.
Li, Daimin
09ca8eed-0bb6-449e-84fc-d6fb4e64f6ed
Ou, Jun Yu
3fb703e3-b222-46d2-b4ee-75f296d9d64d
Xie, Peng
6bd4fc17-78ce-4c75-a2b0-2763dc55c244
Liang, Zhengchen
ec7b2c06-ea5a-46d3-bfc3-270314a88816
Wang, Wei
94191ea2-eaa4-4003-b464-73ef70b5e18c
Wang, Wenxin
76876fd8-f838-4a23-8763-1c8bfecd4b0b
Zhang, Hong
be31ea8d-99eb-4d63-b38d-3cecc1c34112
Kuang, Xiaoyu
352f385f-bded-4e1f-9336-bf8f0f47c338
15 June 2021
Li, Daimin
09ca8eed-0bb6-449e-84fc-d6fb4e64f6ed
Ou, Jun Yu
3fb703e3-b222-46d2-b4ee-75f296d9d64d
Xie, Peng
6bd4fc17-78ce-4c75-a2b0-2763dc55c244
Liang, Zhengchen
ec7b2c06-ea5a-46d3-bfc3-270314a88816
Wang, Wei
94191ea2-eaa4-4003-b464-73ef70b5e18c
Wang, Wenxin
76876fd8-f838-4a23-8763-1c8bfecd4b0b
Zhang, Hong
be31ea8d-99eb-4d63-b38d-3cecc1c34112
Kuang, Xiaoyu
352f385f-bded-4e1f-9336-bf8f0f47c338
Li, Daimin, Ou, Jun Yu, Xie, Peng, Liang, Zhengchen, Wang, Wei, Wang, Wenxin, Zhang, Hong and Kuang, Xiaoyu
(2021)
Spectroscopic study of gap-surface plasmons in a metallic convex groove array and their applications in nanofocusing and plasmonic sensing.
Physical Review B, 103 (24), [245404].
(doi:10.1103/PhysRevB.103.245404).
Abstract
Plasmonic tapered grooves have been proven to be good candidates for the excitation of gap surface plasmons (GSPs), surface plasmons trapped vertically inside a metallic tapered groove or slit. GSPs have attracted tremendous interest due to their unique properties of concentrating light in nanosized gaps with significant field enhancement, thus offering potential applications such as ultracompact nanocircuits, broadband light absorbers, and plasmonic sensors. In this paper, we focus on GSPs supported by periodic arrays of narrow convex grooves and study in detail their properties by using visible-near-infrared (VIS-NIR) spectroscopy. We identify strong second- and third-order GSP modes excited in ultrasharp convex grooves. The dependence of GSP resonances on the groove profile is analyzed with the help of detailed full-wave simulations, revealing the fact that an ultrasharp, but finite, gap exists at the groove bottom and plays a crucial role in determining both the GSP resonance positions and the nanofocusing capability with much improved field enhancement inside the grooves. Spectral shifts of the observed GSP resonances relative to the simulation results are found in a shorter wavelength range and are qualitatively explained as nonlocal effects originating from the nonclassical microscopic behavior of local currents and charges at imperfect interfaces. Utilizing such strong and distinguishable GSP resonance line shapes in an otherwise flat reflectivity spectral baseline, we experimentally demonstrate the capability of convex groove arrays to perform dual-band refractive index sensing in the VIS-NIR range.
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More information
Accepted/In Press date: 18 May 2021
e-pub ahead of print date: 2 June 2021
Published date: 15 June 2021
Additional Information:
This work is supported by the National Natural Science Foundation of China (Grants No. 11974254, No. 61675139, and No. 11974253), the National Key R&D Program of China (Grant No. 2017YFA0303600), the Science Specialty Program of Sichuan University (Grant No. 2020SCUNL210), and the Innovation Program of Sichuan University (Grant No. 2018SCUH0074).
Identifiers
Local EPrints ID: 471350
URI: http://eprints.soton.ac.uk/id/eprint/471350
ISSN: 2469-9950
PURE UUID: 64859c59-7341-46ee-9b4e-39ebe0c695d2
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Date deposited: 03 Nov 2022 17:58
Last modified: 18 Mar 2024 03:18
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Contributors
Author:
Daimin Li
Author:
Jun Yu Ou
Author:
Peng Xie
Author:
Zhengchen Liang
Author:
Wei Wang
Author:
Wenxin Wang
Author:
Hong Zhang
Author:
Xiaoyu Kuang
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