Dielectric tuned circular dichroism of L-shaped plasmonic metasurface

In this paper, a dielectric layer is introduced to tune circular dichroism (CD) of chiral plasmonic metasurfaces. The dielectric layer is used to control the optical phase of electric diploes in Born-Kuhn configurations. To prove our assumption, an L-shaped plasmonic metasurface consisting of two metallic slices is prepared by glancing angle deposition, and then an SiO₂ slice is deposited on one arm of the L-shaped metasurface. Experimental results reveal that CD of the L-shaped plasmonic metasurface can be tuned by the thickness of the SiO₂ slice. These findings not only contribute to a better understanding of the CD physical mechanism, but also can be used in nanophotonic metasurfaces because of the concise fabrication process.