The Floquet Theory, particularly important for the development of new concepts in electro-optics, is used to create time crystals and induce new properties in materials. A study published in Nature Communications presents new, crucial information on the validity of this theory when applied to very short light pulses.
Researchers in the Department of Physics at the Politecnico di Milano, in partnership with the Institute of Photonics and Nanotechnology (IFN-CNR), the University of Tsukaba (Japan) and the Max Planck Institute for the Structure and Dynamics of Matter in Hamburg (Germany), have discovered that a time crystal with unique properties can be induced even with very short pulses, lasting a few millionths of a billionth of a second, or femtoseconds.
The researchers managed to observe the creation of Floquet state of a free electron on this ultrashort time scale, thanks to experiments conducted at the Attosecond Research Center of the Department of Physics at the Politecnico di Milano as part of the ERC project AuDACE (Attosecond Dynamics in AdvanCed matErials). Using simulations based on advanced theoretical models, they demonstrated that the Floquet Theory can be extended to these regimes.
These are significant findings because the possibility to induce new properties in matter with ultrashort light paves the way to the realization of new devices, impossible to obtain with standard techniques.Matteo Lucchini, professor from the Department of Physics and lead author of the study