Topological Nature of Optical Bound States in the Continuum

• Main Authors: Zhen, Bo (Contributor), Hsu, Chia Wei (Contributor), Lu, Ling (Contributor), Stone, A. Douglas (Author), Soljacic, Marin (Contributor)
• Other Authors: Massachusetts Institute of Technology. Materials Processing Center (Contributor), Massachusetts Institute of Technology. Department of Physics (Contributor), Massachusetts Institute of Technology. Research Laboratory of Electronics (Contributor)
• Format: Article
• Language: English
• Published: American Physical Society, 2014-12-19T20:54:09Z.
• Subjects: Article
• Online Access: Get fulltext

Optical bound states in the continuum (BICs) have recently been realized in photonic crystal slabs, where the disappearance of out-of-plane radiation turns leaky resonances into guided modes with infinite lifetimes. We show that such BICs are vortex centers in the polarization directions of far-field radiation. They carry conserved and quantized topological charges, defined by the winding number of the polarization vectors, which ensure their robust existence and govern their generation, evolution, and annihilation. Our findings connect robust BICs in photonics to a wide range of topological physical phenomena.
Massachusetts Institute of Technology. Institute for Soldier Nanotechnologies (Contract W911NF-07-D0001)
United States. Dept. of Energy. Office of Science (Solid-State Solar-Thermal Energy Conversion Center Grant DE-SC0001299)
National Science Foundation (U.S.). Materials Research Science and Engineering Centers (Program) (Grant DMR-0819762)