Observation of Type I Photonic Weyl Points in Optical Frequencies. Issue 2 (20th December 2017)

• Record Type: Journal Article
• Authors: Goi, Elena; Yue, Zengji; Cumming, Benjamin P.; Gu, Min
• Is Part Of: Laser & photonics reviews. Volume 12:Issue 2(2018)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2017-12-20
• Subjects: gyroids -- spin‐angular momentum -- topological photonics -- Weyl points; Lasers -- Periodicals; Photonics -- Periodicals; Lasers -- Périodiques; Photonique -- Périodiques; 621.36
• DOI: 10.1002/lpor.201700271
• Languages: English
• ISSNs: 1863-8880

Abstract

Abstract: Manipulation of momentum space in photonic structures has enabled a range of physical phenomena including negative refraction, slow light, enhanced nonlinearity and three‐dimensional complete bandgaps. Recently, Topology, a property related to the global structure of the frequency dispersion of a photonic system, emerged as a new tool for the control of momentum space and an additional degree of freedom for the discovery of fundamentally new states of light. The Weyl point systems considered in this work are an excellent platform to investigate topological bosonic states. Weyl points act as monopoles or anti‐monopoles Berry flux in momentum space, and carry chirality defined by quantised topological charges. In this work, the experimental realisation of photonic type I Weyl points at optical frequencies is demonstrated in a bio‐inspired three‐dimensional photonic crystal coated uniquely with layered‐composite nanometric materials. More importantly, the chiral nature of the photonic Weyl points is discovered by coupling with spin‐angular momentum carried by circularly polarised light. This Weyl‐point induced mechanism leads to reversed circular dichroism along the directions that intersect the oppositely charged topological photonic states. This discovery provides an entirely new platform for developing topologically protected super‐robust photonic devices in angular‐momentum‐based information processing, circular‐dichroism‐enabled protein sensing, spintronics and quantum optoelectronics. Abstract : Middle‐infrared type‐I Weyl points are detected in bio‐inspired topological micro‐structures coated uniquely with layered‐composite nanometric high‐index materials. More importantly, the chiral character of the photonic Weyl points are experimentally demonstrated through their coupling with spin‐angular momentum carried by circularly polarised light. This Weyl‐point induced mechanism leads to reversed circular dichroism along the directions that intersect the oppositely charged topological photonic states.