报告简介：

Almost all metamaterials derive their properties from an array of subwavelength resonators, and their effective properties can be described by effective permittivity and permeability. We will describe a new type of metamaterials consisting of twisting structures, whose properties are determined the connectivity of the network and not by the resonances of individual elements within a unit cell. Such metamaterials cannot be described using local effective parameters, although the unit cell is deep subwavelength. In contrast to natural materials which have their index ellipsoids centered at k=0, the non-resonant metamaterial can possess multiple index ellipsoids centered at arbitrary nonzero k-points. Such metamaterials can be used to design broadband devices.  We then discuss the realization of Weyl points and 3D Dirac points in 3D topological photonic crystals using twisting structures. One-way edge modes are found on the boundary of these systems and the existence of the boundary modes can be related to the topological invariants of the bulk bands. These phenomena can be understood as a result of the synthetic gauge flux emerging from the twisting structure in real space.

报告人简介：

C.T. Chan received his PhD degree from the University of California at Berkeley in 1985.  He is currently Daniel C K Yu Professor of Science, Chair Professor of Physics at HKUST, the Director of Center for Metamaterial Research and the Director of Research Office of HKUST. He has been elected a Fellow of the American Physical Society and Hong Kong Physical Society. He received the Achievement in Asia Award of the Overseas Chinese Physics Association (2000) and Croucher Senior Research Fellowship (2010). He received the Michael Gale Medal for Distinguished Teaching at HKUST (1999) and is a co-recipient of Brillouin Medal for his research in phononic metamaterials (2013).