Mode evolution and nanofocusing of grating-coupled surface plasmon polaritons on metallic tip

Lu Fanfan; Zhang Wending; Huang Ligang; Liang Shuhai; Mao Dong; Gao Feng; Mei Ting; Zhao Jianlin

doi:10.29026/oea.2018.180010

Opto-Electronic Advances (Jul 2018)

Mode evolution and nanofocusing of grating-coupled surface plasmon polaritons on metallic tip

Lu Fanfan,
Zhang Wending,
Huang Ligang,
Liang Shuhai,
Mao Dong,
Gao Feng,
Mei Ting,
Zhao Jianlin

Affiliations

Lu Fanfan: MOE Key Laboratory of Material Physics and Chemistry under Extraordinary Conditions and Shaanxi Key Laboratory of Optical Information Technology, School of Science, Northwestern Polytechnical University, Xi'an 710072, China
Zhang Wending: MOE Key Laboratory of Material Physics and Chemistry under Extraordinary Conditions and Shaanxi Key Laboratory of Optical Information Technology, School of Science, Northwestern Polytechnical University, Xi'an 710072, China
Huang Ligang: Key Laboratory of Optoelectronic Technology and Systems (Ministry of Education), Chongqing University, Chongqing 400044, China
Liang Shuhai: MOE Key Laboratory of Material Physics and Chemistry under Extraordinary Conditions and Shaanxi Key Laboratory of Optical Information Technology, School of Science, Northwestern Polytechnical University, Xi'an 710072, China
Mao Dong: MOE Key Laboratory of Material Physics and Chemistry under Extraordinary Conditions and Shaanxi Key Laboratory of Optical Information Technology, School of Science, Northwestern Polytechnical University, Xi'an 710072, China
Gao Feng: MOE Key Laboratory of Weak-Light Nonlinear Photonics, TEDA Applied Physics Institute and School of Physics, Nankai University, Tianjin 300457, China
Mei Ting: MOE Key Laboratory of Material Physics and Chemistry under Extraordinary Conditions and Shaanxi Key Laboratory of Optical Information Technology, School of Science, Northwestern Polytechnical University, Xi'an 710072, China
Zhao Jianlin: MOE Key Laboratory of Material Physics and Chemistry under Extraordinary Conditions and Shaanxi Key Laboratory of Optical Information Technology, School of Science, Northwestern Polytechnical University, Xi'an 710072, China

DOI: https://doi.org/10.29026/oea.2018.180010
Journal volume & issue: Vol. 1, no. 6
pp. 180010-1 – 180010-7

Abstract

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We present a detailed analysis on mode evolution of grating-coupled surface plasmonic polaritons (SPPs) on a conical metal tip based on the guided-wave theory. The eigenvalue equations for SPPs modes are discussed, revealing that cylindrical metal waveguides only support TM01 and HEm1 surface modes. During propagation on the metal tip, the grating-coupled SPPs are converted to HE31, HE21, HE11 and TM01 successively, and these modes are sequentially cut off except TM01. The TM01 mode further propagates with drastically increasing effective mode index and is converted to localized surface plasmons (LSPs) at the tip apex, which is responsible for plasmonic nanofocusing. The gap-mode plasmons can be excited with the focusing TM01 mode by approaching a metal substrate to the tip apex, resulting in further enhanced electric field and reduced size of the plasmonic focus.

Published in Opto-Electronic Advances

ISSN: 2096-4579 (Print)
Publisher: Institue of Optics and Electronics, Chinese Academy of Sciences
Country of publisher: China
LCC subjects: Science: Physics: Optics. Light
Website: http://www.oejournal.org/oea

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