Ultrathin Planar Cavity Metasurfaces

Hsiang-Chu Wang, Cheng Hung Chu, Pin Chieh Wu, Hui-Hsin Hsiao, Hui Jun Wu, Jia-Wern Chen, Wei Hou Lee, Yi-Chieh Lai, Yao-Wei Huang, Ming Lun Tseng, Shu-Wei Chang, Din Ping Tsai*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

19 Scopus citations

Abstract

An ultrathin planar cavity metasurface is proposed based on ultrathin film interference and its practicability for light manipulation in visible region is experimentally demonstrated. Phase of reflected light is modulated by finely adjusting the thickness of amorphous silicon (a-Si) by a few nanometers on an aluminum (Al) substrate via nontrivial phase shifts at the interfaces and interference of multireflections generated from the planar cavity. A phase shift of pi, the basic requirement for two-level phase metasurface systems, can be accomplished with an 8 nm thick difference. For proof of concept, gradient metasurfaces for beam deflection, Fresnel zone plate metalens for light focusing, and metaholograms for image reconstruction are presented, demonstrating polarization-independent and broadband characteristics. This novel mechanism for phase modulation with ultrathin planar cavity provides diverse routes to construct advanced flat optical devices with versatile applications.

Original languageEnglish
Article number1703920
Number of pages6
JournalSmall
Volume14
Issue number17
DOIs
StatePublished - 26 Apr 2018

Keywords

  • beam deflection
  • Fresnel zone plates
  • metaholograms
  • metasurfaces
  • ultrathin planar cavities
  • ORBITAL ANGULAR-MOMENTUM
  • BROAD-BAND
  • PHASE DISCONTINUITIES
  • POLARIZATION
  • REFLECTION
  • GRADIENT
  • ROBUST

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