Floquet Physics in intense lasers and attosecond timescales

When matter is irradiated by a time-periodic laser pulse, the system can enter into a light-dressed Floquet phase of matter, which is an out-of-equilibrium steady-state phase. Typically, Floquet physics is explored in the regime of weak laser driving, where the electric field perturbs the Hamiltonian and causes small modifications to the system’s band structure. Such dynamics have been measured in multiple systems, and used for controlling material quantum properties such as topology.

We are interested in understanding the role of Floquet physics in a much more intense regime of light-matter interactions, where non-perturbative attosecond electron dynamics are simultaneously occurring. Our goal is to understand whether or not Floquet phases form in such conditions, what they look like, how to control them, as well as to develop methodologies for their detection based on HHG spectroscopy and time- and angle-resolved photoelectron spectroscopy (Tr-ARPES). We are especially interested in exploring the role of sub-laser-cycle attosecond dynamics in Floquet physics.