Three-dimensional all-dielectric photonic topological insulator

• DOI: 10.1038/nphoton.2016.253
• Publication Date: 2016-12-26T16:32:44Z
• Authors: Alexey Slobozhanyuk; S. Hossein Mousavi; Xiang Ni; Daria Smirnova; Yuri S. Kivshar; Alexander B. Khan...
• Keywords: Topological insulator; Surface States

17 pages, 5 figures<br/>The discovery of two-dimensional topological photonic systems has transformed our views on electromagnetic propagation and scattering of classical waves, and a quest for similar states in three dimensions, known to exist in condensed matter systems, has been put forward. Here we demonstrate that symmetry protected three-dimensional topological states can be engineered in an all-dielectric platform with the electromagnetic duality between electric and magnetic fields ensured by the structure design. Magneto-electric coupling playing the role of a synthetic gauge field leads to a topological transition to an insulating regime with a complete three-dimensional photonic bandgap. An emergence of surface states with conical Dirac dispersion and spin-locking is unimpeded. Robust propagation of surface states along two-dimensional domain walls defined by the reversal of magneto-electric coupling is confirmed numerically by first principle studies. It is shown that the proposed system represents a table-top platform for emulating relativistic physics of massive Dirac fermions and the surface states revealed can be interpreted as Jackiw-Rebbi states confined to the interface between two domains with opposite particle masses.<br/>