Ultrathin Suspended Chiral Metasurfaces for Enantiodiscrimination.

Cen, Mengjia; Wang, Jiawei; Liu, Jianxun; He, Huilin; Li, Ke; Cai, Wenfeng; Cao, Tun; Liu, Yan Jun · Adv Mater · 2022

basic_science · Level V

Where this comes from

Abstract

Chiral metasurfaces can exhibit a strong circular dichroism, but it is limited by the complicated fabrication procedure and alignment errors. Here, a new type of self-aligned suspended chiral bilayer metasurface with only one-step electron beam lithography exposure is demonstrated. A significant optical chirality of 221° µm<sup>-1</sup> can be realized using suspended metasurfaces with a thickness of 100 nm. Furthermore, this study experimentally demonstrates that such a structure is capable of label-free discrimination of the chiral molecules at zeptomole level, exhibiting a much higher sensitivity (orders of magnitude) compared to the conventional circular dichroism spectroscopy. The fundamental principles for chiral sensing using molecules-metasurfaces interactions are explored. Benefiting from the giant chiroptical response, the proposed metadevice may offer promising applications for ultrathin circular polarizers, chiral molecular detectors, and asymmetry information processing.