Due to the recent discovery of topological insulators, it has been recognized that topology is indispensable in distinguishing phases of matter. Similarly, new optical material systems are being discovered with non-trivial topologies of their global wave-functions in the momentum space, whose interfaces support novel states of light with ideal transport properties such as the robustness to large disorder or fabrication imperfections.
In this talk, I will show our experimental realizations and theoretical predictions of 2D and 3D photonic crystals with topologically protected edge and surface states. Specifically, I will discuss single and multimode one-way waveguides, the observation of Weyl points, a single Dirac cone surface state immune to random disorder and topological one-way fibers. This research can be extended to phonons, plasmons and other bosons. These new degrees of freedom in bosonic band topologies promise wide exciting opportunities in both fundamental physics and technological outcomes.