The 2016 Nobel Prize in Physics was awarded to Kosterlitz, Thouless, and Haldane for their pioneering theoretical work on the novel and counter-intuitive phases of matter that are now referred to as topological phases. Almost half a century after these researchers applied powerful mathematical techniques of topology to condensed matter systems, a new rapidly developing area is taking shape, now in the field of photonics. While very different in many respects from their condensed matter counterparts, topological phases of light share some of their unique properties that make topological photonics particularly suitable for practical applications. Just as the inventors of photonic crystals (often referred to as the “semiconductors of light”) borrowed crucial ideas, such as propagation bands, bandgaps, and Brillouin zone, from condensed matter physics, so do the researchers in the field of topological photonics that attempts to emulate the key concepts from low-dimensional topological materials. Those include photonic topological insulators (PTIs), reflection-less edge states that propagate along the domain walls of the PTIs, and spin-polarized/valley-polarized transport.

In this talk, Dr. Shvets will provide an overview of the field, with special emphasis on the photonic emulation of the canonical quantum topological phases such as the Hall, spin-Hall, and valley-Hall phases. He will then describe how such heterogeneous PTIs can be integrated and used for developing novel devices such as compact circulators. Experimental results demonstrating reflection-less transport of topologically protected edge states will be presented. He will also discuss how the ideas from topological photonics can be used for complete reimagining of the architectures of photonic devices such as add/drop filters, delay lines, and logical gates based on the valley degree of freedom of photons (“photonic valleytronics”). Finally, Dr. Shvets will discuss the prospects of realizing reconfigurable topological photonic structures on a nanoscale. The prospects for exciting topologically protected microwaves using high current beams, and using the latter for high-power magnets-free microwave radiation, will also be discussed.