Observation of Ultrafast THz Self-actions in Graphene Based Modulators

Over the last two decades, terahertz (THz) radiation has attracted a constantly growing attention and has been routinely applied in a variety of applications, such as medical diagnostics, industrial quality control, food inspection and many others [1] . A new era of applications, that of THz wireless communication opens up ahead revealing the high importance of the development of fast modulation devices operating at the THz part of the electromagnetic spectrum. Towards this direction many devices based on graphene have been proposed to modulate radiation at THz frequencies. For example, a perfect absorber device based on a cavity of monolayer graphene over a grounded dielectric that can be tuned by an electrostatic gate was demonstrated in the low THz regime [2] . Under the same concept it was experimentally shown that the THz absorption of such device can be modulated in an ultrafast way via an optical pump signal [3] .