Dimitris N. Chorafas Foundation Award 2016 – Michele Tamagnone

“For developing for the first time several reconfigurable Terahertz components using graphene, including a beam steering reflectarray and an isolator. These components open the door to novel THz applications in the areas of security, short-range telecommunications, spectroscopy and bio-sensors. In addition, an original theoretical formalism has allowed the design of quasi-optimum components.”

This thesis explores the applications of graphene for terahertz and far infrared optical components and antennas, with particular emphasis on tunable and non-reciprocal devices. Both terahertz technologies and graphene are emerging fields which hold many promises for a number of future applications, including ultra-broadband communications, sensing and security. The first original contribution of this thesis is an important theoretical upper bound for the performance of non-reciprocal and tunable devices. This theoretical limit is an important guideline for the design of graphene optical devices, as it can predict the best possible performances prior to any design effort or numerical simulation. The potential of graphene for non-reciprocal applications is then demonstrated experimentally, with the design, fabrication and measurement of the first terahertz isolator. Our device is shown to be quasi-optimum according to the theoretical upper bound. The thesis explores then a number of designs of graphene antennas for terahertz and mid infrared frequencies, and, finally, the first tunable graphene reflectarray is presented, which is a metasurface able to steer in a desired direction an incoming beam of terahertz radiation.