Controlled THz Generation by Nonlinear Metasurfaces

 In the last couple of decades, there have been dramatic advances in the generation, manipulation, and detection capabilities of THz waves (0.1-10 THz). These advances forecast a variety of emerging desirable applications. However, despite the immense recent progress in THz technologies, there is still a substantial lack of simple methods to generate fully controlled THz waveforms. In my talk, I will present the recent advancements in the ability of nano-engineered plasmonic metasurfaces to generate broadband and highly controlled THz waves. I will elucidate the underlying physical mechanisms that make the THz emission from the metasurfaces comparable in strength to that emitted from orders of magnitude thicker nonlinear crystals, excited at the same conditions. I will also show that simple electromagnetic considerations allow to further enhance the THz radiation from the metasurfaces by more than an order of magnitude. In addition, I will demonstrate how to utilize the well-known Pancharatnam-Berry phase to obtain unprecedented spatio-temporal control over the amplitude, phase, and polarization of the emitted THz waves, opening the door for holographic THz emitters.