Far-field optical imaging of surface plasmons with a subdiffraction limited separation
Xiang Yifeng,
Chen Junxue,
Tang Xi,
Wang Ruxue,
Zhan Qiwen,
Lakowicz Joseph R.,
Zhang Douguo
Affiliations
Xiang Yifeng
Key Laboratory of OptoElectronic Science and Technology for Medicine of Ministry of Education, Fujian Provincial Key Laboratory of Photonics Technology, College of Photonic and Electronic Engineering, Fujian Normal University, Fuzhou 350117, China
Chen Junxue
College of Science, Guilin University of Technology, Guilin, 541004, China
Tang Xi
Department of Optics and Optical Engineering, Institute of Photonics, University of Science and Technology of China, Hefei, Anhui, 230026, China
Wang Ruxue
State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai, 200050, China
Zhan Qiwen
Department of Electro-Optics and Photonics, University of Dayton, 300 College Park, Dayton, OH, 45469-2951, USA
Lakowicz Joseph R.
Department of Biochemistry and Molecular Biology, Center for Fluorescence Spectroscopy, University of Maryland School of Medicine, 725 West Lombard St., Baltimore, MD, 21201, USA
Zhang Douguo
Department of Optics and Optical Engineering, Institute of Photonics, University of Science and Technology of China, Hefei, Anhui, 230026, China
When an ultrathin silver nanowire with a diameter less than 100 nm is placed on a photonic band gap structure, surface plasmons can be excited and propagate along two side-walls of the silver nanowire. Although the diameter of the silver nanowire is far below the diffraction limit, two bright lines can be clearly observed at the image plane by a standard wide-field optical microscope. Simulations suggest that the two bright lines in the far-field are caused by the unique phase distribution of plasmons on the two side-walls of the silver nanowire. Combining with the sensing ability of surface plasmons to its environment, the configuration reported in this work is capable of functioning as a sensing platform to monitor environmental changes in the near-field region of this ultrathin nanowire.
