title: Optical activity enhanced by strong inter-molecular coupling in planar chiral metamaterials.
abstract: The polarization of light can be rotated in materials with an absence of molecular or structural mirror symmetry. While this rotating ability is normally rather weak in naturally occurring chiral materials, artificial chiral metamaterials have demonstrated extraordinary rotational ability by engineering intra-molecular couplings. However, while in general, chiral metamaterials can exhibit strong rotatory power at or around resonances, they convert linearly polarized waves into elliptically polarized ones. Here, we demonstrate that strong inter-molecular coupling through a small gap between adjacent chiral metamolecules can lead to a broadband enhanced rotating ability with pure rotation of linearly polarized electromagnetic waves. Strong inter-molecular coupling leads to nearly identical behaviour in magnitude, but engenders substantial difference in phase between transmitted left and right-handed waves.
authors.affiliation: 1] Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology(KAIST), Daejeon 305-701, Republic of Korea [2] [3].
authors.forename: Teun-Teun
authors.initials: TT
authors.lastname: Kim
authors.affiliation: 1] The Blackett Laboratory, Department of Physics, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom [2].
authors.forename: Sang Soon
authors.initials: SS
authors.lastname: Oh
authors.affiliation: Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology(KAIST), Daejeon 305-701, Republic of Korea.
authors.forename: Hyun-Sung
authors.initials: HS
authors.lastname: Park
authors.affiliation: The Blackett Laboratory, Department of Physics, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom.
authors.forename: Rongkuo
authors.initials: R
authors.lastname: Zhao
authors.affiliation: Advanced Photonics Research Institute, GIST, Gwangju, 500-712, Republic of Korea.
authors.forename: Seong-Han
authors.initials: SH
authors.lastname: Kim
authors.affiliation: Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701, Republic of Korea.
authors.forename: Wonjune
authors.initials: W
authors.lastname: Choi
authors.affiliation: Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology(KAIST), Daejeon 305-701, Republic of Korea.
authors.forename: Bumki
authors.initials: B
authors.lastname: Min
authors.affiliation: The Blackett Laboratory, Department of Physics, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom.
authors.forename: Ortwin
authors.initials: O
authors.lastname: Hess