Enantiomer-Selective Molecular Sensing via Upconverted Chiral Metamaterials

Chirality in Nature is a physical property that cannot be superimposable on each other. At the molecular scale, the spatial asymmetry of atomic configuration contributes to a fascinating yet dramatic difference in chemical and physical characteristics. Discriminating enantiomers via optical techniques has been primarily employed since it enables nondestructive characterization; however, enantiomers show these signatures in the ultraviolet region, which limits the versatile application for biochemical species. Here, we proposed a simple but effective method to discriminate chiral molecules via asymmetric behavior of plasmonic metamaterial, leading to the selective optical response in a nonlinear regime. The enantiomers dissimilarly interact with the plasmonic chiral metamaterial, which gives rise to a change in the circular dichroism of chiral metamaterial in the near-infrared region by chirality transfer effect. The distinction of the circular dichroism is clarified by the upconverted photoluminescence in the visible region.