Scattering analysis and efficiency optimization of dielectric pancharatnam-berry-phase metasurfaces

Chen Yi Yu, Qiu Chun Zeng, Chih Jen Yu, Chien Yuan Han, Chih Ming Wang

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

In this study, the phase modulation ability of a dielectric Pancharatnam-Berry (PB) phase metasurface, consisting of nanofins, is theoretically analyzed. It is generally considered that the optical thickness of the unit cell of a PB-phase metasurface is λ/2, i.e., a half-waveplate for polarization conversion. It is found that the λ/2 is not essential for achieving a full 2π modulation. Nevertheless, a λ/2 thickness is still needed for a high polarization conversion efficiency. Moreover, a gradient phase metasurface is designed. With the help of the particle swarm optimization (PSO) method, the wavefront errors of the gradient phase metasurface are reduced by fine-tuning the rotation angle of the nanofins. The diffraction efficiency of the gradient phase metasurface is thus improved from 73.4% to 87.3%. This design rule can be utilized to optimize the efficiency of phase-type meta-devices, such as meta-deflectors and metalenses.

Original languageEnglish
Pages (from-to)1-10
Number of pages10
JournalNanomaterials
Volume11
Issue number3
DOIs
StatePublished - Mar 2021

Keywords

  • Metasurface
  • PB-phase
  • Polarization

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