Events Calendar

Disorder-immune slow light with topological electromagnetic modes

Speaker: Dr. Zheng Wang, MITAbstract: Chiral edge states were discovered around 30 years ago in quantum Hall effects in 2D electron gas. They are the underlying mechanism that supports dissipationless transport of electrons in quantum Hall systems and quantum spin Hall systems. Although they were only observed in fermionic systems, such as electrons in graphene, our work experimentally demonstrates, for the first time, that chiral edge states also exist for photonic systems.Light can be confined and routed using structures known as waveguides. The slimmest waveguides, known as "single-mode waveguides", allow light to propagate only in one spatial configuration either in forward or backward direction. Using photonic chiral edge states, we can force light to propagate only in one spatial configuration and only in one direction, essentially creating "half-mode waveguides".When the possibility of traveling backwards is eliminated, light exhibits fascinating and unparalleled properties. For instance, scattering can be completely suppressed, even in the presence of very large disorder. With a waveguide highly tolerant to large imperfection, a wide range of practical applications from electromagnetic isolation, to slow light and optical buffering may benefit.Biography: Dr. Zheng Wang is currently a postdoctoral researcher at the Massachusetts Institute of Technology. He received his PhD in Applied Physics from Stanford University in 2006.

Location: Frank R. Seaver Science Center (SSC) - 319

Audiences: Everyone Is Invited

Contact: Michelle Povinelli