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Optical Möbius symmetry in metamaterials
Chih-Wei Chang1, Ming Liu, Sunghyun Nam
1Nanoscale Science and Engineering Center, 3112 Etcheverry Hall, University of California, Berkeley, California 94720-1740, USA.
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.
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