Refractive index conjugate all-dielectric cylindrical array metasurface reflection enhancement effect study

Abstract

To investigate the enhancement effect of the reflection spectra in the metasurface, a cylindrical tetramer array metasurface structure based on the principle of PT (Parity-Time) symmetry is proposed. The construction of cylindrical array structures satisfying the refractive index conjugation condition by doping quantum dots in the metasurface. Based on the principle of PT symmetry, the mechanism of the reflection enhancement effect of this metasurface is investigated. Furthermore, the evolution of the reflection spectra changes with the geometric parameter and arrangement of the cylinder are discussed, respectively. In the proposed metasurface, the plane waves under normal incidence can directly excite peaks with reflectivity larger than 1. This peak is robust to the number and arrangement of cylinders in the unit cell. Through the rational design of various structural parameters, the peak reflectivity of this structure reaches 10401 and the sensitivity achieves S=5.5×106RIU−1. The designed structure in this paper breaks the threshold of reflectivity of less than 1 in conventional optical structures, achieving a reflection enhancement effect and improving detection sensitivity. This study provides a reference for the combination of the PT symmetry principle and the metasurface structure to achieve better sensing performance.