title: Chirality detection of enantiomers using twisted optical metamaterials.
abstract: Many naturally occurring biomolecules, such as amino acids, sugars and nucleotides, are inherently chiral. Enantiomers, a pair of chiral isomers with opposite handedness, often exhibit similar physical and chemical properties due to their identical functional groups and composition, yet show different toxicity to cells. Detecting enantiomers in small quantities has an essential role in drug development to eliminate their unwanted side effects. Here we exploit strong chiral interactions with plasmonic metamaterials with specifically designed optical response to sense chiral molecules down to zeptomole levels, several orders of magnitude smaller than what is typically detectable with conventional circular dichroism spectroscopy. In particular, the measured spectra reveal opposite signs in the spectral regime directly associated with different chiral responses, providing a way to univocally assess molecular chirality. Our work introduces an ultrathin, planarized nanophotonic interface to sense chiral molecules with inherently weak circular dichroism at visible and near-infrared frequencies.
authors.affiliation: Department of Electrical and Computer Engineering, The University of Texas at Austin, 1 University Station, Austin, Texas 78712, USA.
authors.forename: Yang
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: Department of Electrical and Computer Engineering, The University of Texas at Austin, 1 University Station, Austin, Texas 78712, USA.|Department of Electrical Engineering, Amirkabir University of Technology, 424 Hafez Avenue, Tehran 15875-4413, Iran.
authors.forename: Amir N
authors.initials: AN
authors.lastname: Askarpour
authors.affiliation: Department of Physics, The University of Texas at Austin, 1 University Station, Austin, Texas 78712, USA.
authors.forename: Liuyang
authors.initials: L
authors.lastname: Sun
authors.affiliation: Department of Physics, Beijing Normal University, 19 Xinjiekou Outer Street, Beijing 100875, China.
authors.forename: Jinwei
authors.initials: J
authors.lastname: Shi
authors.affiliation: Department of Physics, The University of Texas at Austin, 1 University Station, Austin, Texas 78712, USA.
authors.forename: Xiaoqin
authors.initials: X
authors.lastname: Li
authors.affiliation: Department of Electrical and Computer Engineering, The University of Texas at Austin, 1 University Station, Austin, Texas 78712, USA.
authors.forename: Andrea
authors.initials: A
authors.lastname: Alù