An all-dielectric chiral metasurface with circular dichroism and asymmetric transmission characteristics

Abstract:

This paper designs an all-dielectric metasurface with tunable chiral properties in the near-infrared range, whose working wavelength is 1 250—2 200 nm. The metasurface exhibits circular dichroism (CD) and asymmetric transmission (AT) characteristics for circularly polarized light. The metasurface is a double-layer structure composed of Ge2Sb2Se4Te1 (GSST). The CD values of amorphous GSST reach 0.83 and 0.82 at 1 570 nm and 1 640 nm, respectively. The AT values reach 0.65 and 0.77 at 1 570 nm and 1 640 nm, respectively, with a value of −0.62 at 1 680 nm. The CD value of crystalline GSST reaches 0.81 at 2 070 nm, with smaller AT. In addition, whether it is incident by linearly polarized waves or circularly polarized waves, this metasurface has low absorption in the working band, which gives it the potential to make adjustable integrated photonic devices.