title: Optical Möbius symmetry in metamaterials.
abstract: We experimentally observed a new topological symmetry in optical composites, namely, metamaterials. While it is not found yet in nature materials, the electromagnetic Möbius symmetry discovered in metamaterials is equivalent to the structural symmetry of a Möbius strip, with the number of twists controlled by the sign change of the electromagnetic coupling between the meta-atoms. We further demonstrate that metamaterials with different coupling signs exhibit resonance frequencies that depend only on the number but not the locations of the "twists," thus confirming its topological nature. The new topological symmetry found in metamaterials may enable unique functionalities in optical materials.
authors.affiliation: Nanoscale Science and Engineering Center, 3112 Etcheverry Hall, University of California, Berkeley, California 94720-1740, USA.
authors.forename: Chih-Wei
authors.initials: CW
authors.lastname: Chang
authors.forename: Ming
authors.initials: M
authors.lastname: Liu
authors.forename: Sunghyun
authors.initials: S
authors.lastname: Nam
authors.forename: Shuang
authors.initials: S
authors.lastname: Zhang
authors.forename: Yongmin
authors.initials: Y
authors.lastname: Liu
authors.forename: Guy
authors.initials: G
authors.lastname: Bartal
authors.forename: Xiang
authors.initials: X
authors.lastname: Zhang