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Training and Research Experiences in Nonlinear Dynamics

Optical Nonlinearity in Topological Systems

Mohammad Hafezi

Physicists classify and understand systems in terms of many properties: color, mass, and length are familiar examples. Another interesting feature is a system's topology, or how its parts connect. As an example, a circular-linked necklace can be deformed into an oval or a rectangle without changing the topology, since the links remain connected in the same way. But when the necklace is broken or unclasped, it becomes a topologically distinct straight line. 

In the 1980s, physicists realized that some physical properties are entirely dictated by a system's topology. Hafezi's group investigates topological features in optical systems to explore new physics and develop optical devices with built-in protection for potential applications in classical and quantum information processing.

Hafezi's platform is silicon-on-insulator technology and, as a result, investigations could have a significant impact in optoelectronics. 

TREND students working in this area will investigate the role of nonlinearity in topological systems. They will gain experimental skills for working with optical systems as well as analytical skills for exploring these systems. 

Additional information about Prof. Hafezi's research can be found at and by contacting Mohammad Hafezi at or 301-405-2630.