Wideband High-Reflection Chiral Dielectric Metasurface

Compared to natural materials, artificial subwavelength structures can enhance chiroptical effects in a stronger way, and the requirement of low material loss and wideband operation is desired in many situations. Here, we propose an all-dielectric chiral metasurface as a periodic array of centrosymmetric staggered silicon cuboid pairs to achieve strong circular dichroism in a wide band. As a demonstration, the designed chiral metasurface may strongly reflect the chosen circularly polarized light with the spin preserved in the operating wavelength range of 1.51 ti 1.60 mu m while highly transmit (with an efficiency greater than 95%) the opposite circularly polarized light with the spin flipped. Then, two application cases are given for the designed chiral metasurface. A flat chiral meta-lens is constructed to produce wideband focusing in the transmission/reflection side while the disturbing from the opposite circular polarization is well blocked by high reflection/transmission. A chiral Fabry-Perot cavity is also constructed, which has an extremely high quality factor (2.1E4). The proposed method provides an efficient way to produce strong chiroptical effects and has a promising potential for various applications such as signal processing, sensing, radiation and detection.

Automated summary

Artificial subwavelength structures can enhance chiroptical effects, and the design of an all-dielectric chiral metasurface achieves strong circular dichroism in a wide band, with an operating wavelength range of 1.51 to 1.60 micrometers and over 95% transmission efficiency. By constructing a flat chiral meta-lens and a chiral Fabry-Perot cavity, it can be efficiently applied in various fields such as signal processing, sensing, radiation, and detection.