中国物理B ›› 2014, Vol. 23 ›› Issue (3): 34213-034213.doi: 10.1088/1674-1056/23/3/034213

• ELECTROMAGNETISM, OPTICS, ACOUSTICS, HEAT TRANSFER, CLASSICAL MECHANICS, AND FLUID DYNAMICS • 上一篇    下一篇

Subwavelength beam manipulation via multiple-metal slits coupled by disk-shaped nanocavity

郑改革, 徐林华, 裴世鑫, 陈云云   

  1. School of Physics and Optoelectronic Engineering, Nanjing University of Information Science & Technology, Nanjing 210044, China
  • 收稿日期:2013-05-23 修回日期:2013-07-15 出版日期:2014-03-15 发布日期:2014-03-15
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant No. 61203211), the Natural Science Foundation of Jiangsu Higher Education Institutions of China (Grant No. 13KJB140006), and the Foundation for Outstanding Young Teachers of Nanjing University of Information Science & Technology, China (Grant No. 20110423).

Subwavelength beam manipulation via multiple-metal slits coupled by disk-shaped nanocavity

Zheng Gai-Ge (郑改革), Xu Lin-Hua (徐林华), Pei Shi-Xin (裴世鑫), Chen Yun-Yun (陈云云)   

  1. School of Physics and Optoelectronic Engineering, Nanjing University of Information Science & Technology, Nanjing 210044, China
  • Received:2013-05-23 Revised:2013-07-15 Online:2014-03-15 Published:2014-03-15
  • Contact: Zheng Gai-Ge E-mail:eriot@126.com
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant No. 61203211), the Natural Science Foundation of Jiangsu Higher Education Institutions of China (Grant No. 13KJB140006), and the Foundation for Outstanding Young Teachers of Nanjing University of Information Science & Technology, China (Grant No. 20110423).

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摘要： A novel plasmonic structure consisting of three nano-scaled slits coupled by nano-disk-shaped nanocavities is proposed to produce subwavelength focusing and beam bending at optical frequencies. The incident light passes through the metal slits in the form of surface plasmon polaritons (SPPs) and then scatters into radiation fields. Numerical simulations using finite-difference time-domain (FDTD) method show that the transmitted fields through the design example can generate light focusing and deflection by altering the refractive index of the coupled nanocavity. The simulation results indicate that the focal spot is beyond the diffraction limit. Light impinges on the surface at an angle to the optical axis will add an extra planar phase front that interferes with the asymmetric phase front of the plasmonic lens, leading to a larger bending angle off the axial direction. The advantages of the proposed plasmonic lens are smaller device size and ease of fabrication. Such geometries offer the potential to be controlled by using nano-positioning systems for applications in dynamic beam shaping and scanning on the nanoscale.

关键词: beam manipulation, surface plasmon, subwavelength slits

Abstract: A novel plasmonic structure consisting of three nano-scaled slits coupled by nano-disk-shaped nanocavities is proposed to produce subwavelength focusing and beam bending at optical frequencies. The incident light passes through the metal slits in the form of surface plasmon polaritons (SPPs) and then scatters into radiation fields. Numerical simulations using finite-difference time-domain (FDTD) method show that the transmitted fields through the design example can generate light focusing and deflection by altering the refractive index of the coupled nanocavity. The simulation results indicate that the focal spot is beyond the diffraction limit. Light impinges on the surface at an angle to the optical axis will add an extra planar phase front that interferes with the asymmetric phase front of the plasmonic lens, leading to a larger bending angle off the axial direction. The advantages of the proposed plasmonic lens are smaller device size and ease of fabrication. Such geometries offer the potential to be controlled by using nano-positioning systems for applications in dynamic beam shaping and scanning on the nanoscale.

Key words: beam manipulation, surface plasmon, subwavelength slits

中图分类号:  (Reflectors, beam splitters, and deflectors)

  • 42.79.Fm
42.25.-p (Wave optics) 78.68.+m (Optical properties of surfaces)