Photonics experiment and theory: my group explores the linear, nonlinear, and quantum optics of complex photonic structures. One example is the new field of topological photonics - just recently, we showed that light could be protected from scattering in a photonic crystal structure much as electrons are in a solid-state topological insulator (Rechtsman et al., Nature 496, 196-200 (2013)). What are the device implications for this robustness of photon transport? Can we topologically protect photonic quantum information? Can we use these ideas to bulid tiny optical diodes? How will photon interactions (nonlinearity) alter topological effects?