Speaker: Prof. Guy Bartal

Gathering - 12:30

Lecture – 13:00-14:00

Auditorium 011, Engineering Class Room Building,

Faculty of Engineering, Tel-Aviv University

Abstract:

Topological defects are field configurations which cannot be deformed to a standard, smooth shape. They are at the core of many fascinating phenomena in hydrodynamics, aerodynamics, exotic phases of matter,  cosmology and optics  and, in many cases, are of importance to practical applications. The intricate dynamics of a multitude of topological defects and the efforts to control them are of key importance in high-temperature superconductivity and topological phase transitions such as the Berezinskii–Kosterlitz–Thouless transition.

In optics, topological defects were first extensively explored via phase and polarization singularities, both in free-space propagating light and two-dimensionally confined light. In the past decade, topological phenomena have been a source of avid research, inspired by the first observation of photonic topological insulators on one hand, and plasmonic vortices on the other.

Here, I will present our recent results showing control over various topologies of Surface Plasmon Polaritons, ranging from nano-scale tuning of the spatial location of optical singularities to Optical Skyrmions lattice. This is achieved by excitation of  surface plasmons using specifically-designed coupling slits so as to generate the different topologies. The full Electro-Magnetic field of the plasmons is measured and characterized by means of phase-resolved near-field optical microscopy