Stefano Bonetti
The interaction between light and matter is and it has been at the heart of our understanding of condensed matter physics, and of physics at large. Historically, the development of previously unavailable light sources, extending both the achievable wavelength and brightness ranges, have greatly impacted fundamental research and eventually technology, such as for the case of the laser. In this talk, I will focus on coherent THz radiation of large amplitude, i.e. with electric fields of the order of 1 MV/cm and magnetic fields in the 0.1 – 1 Tesla range, and its interaction with magnetic materials. Thanks to these strong THz fields, we have recently been able to experimentally discover an elusive phenomenon in condensed matter: the evidence of magnetic "nutation", predicted over 10 years ago, which I will discuss in detail in the presentation. Then, I will discuss our efforts of designing THz metamaterials aimed at enhancing the magnetic field component to reach the few Tesla range, opening up for nonlinear driving of magnetic excitations in ferromagnets and antiferromagnets.