ABSTRACT
The study on manipulating classical waves can date back to thousands of years ago, while the modern evolution in this classical field was propelled by the invention of photonic and phononic crystals around three decades ago. More recently, people started to classify the band structures of these man-made crystals in terms of band topology which then led to the newly emerging field of topological photonics and phononics. Topology offers new possibilities in controlling the wave propagation. This talk consists of two main parts. In the first part, I will talk about various kind of topological semimetals and their realization in classical waves, including Weyl semimetals, charged nodal line (chain) semimetals and nodal surface semimetals. In the second part, I will talk about an analogue of quantum spin Hall effect in classical waves by utilizing the orbital angular degree of freedom. The idea in this part will be illustrated with a tight-binding model and also experimentally demonstrated with a transmission line network.
BIOGRAPHY
Meng XIAO is currently an assistant professor in Wuhan University. Before that, he was a postdoc working with Prof. Shanhui Fan in the electrical engineering department of Stanford University. He got his Ph. D. from the Hong Kong University of Science and Technology (Supervisor: Prof. C. T. Chan) and bachelor’s degree from Wuhan University. Dr. Xiao has worked on topics such as metamaterials, and Zak phases and topological transition in one-dimensional systems. Now he is mainly interested in the geometric and topological phases of classical waves, including but not limited to electromagnetic waves, acoustic waves and elastic waves.