Title: Changing matter, faster than light
When: Wednesday, October 15, 2025, 15:00
Place: Department of Theoretical Condensed Matter Physics, Faculty of Sciences, Module 5, Seminar Room (5th Floor)
Speaker: Emanuele Galiffi / IFIMAC-UAM
In conventional materials, light encounters linear electromagnetic properties that are time-independent, or at most vary slowly compared to its oscillation cycle. Recently, a new class of artificial photonic materials called time-metamaterials have challenged this paradigm. In this talk I will discuss artificial structures that leverage subwavelength arrays of active or passive switches that can homogeneously (or inhomogeneously) modify the effective electromagnetic properties of the entire device at sub-cycle timescales, enabling a host of opportunities for advanced wave manipulation, such as temporal reflection, photonic collisions, broadband pulse shaping and broadband frequency translation. In particular, I will focus on how the energy dynamics in these electromagnetic wave systems can be manipulated by tailoring these time-varying metamaterials at the microscopic and the macroscopic scales, and how these insights pave the way for advanced wave manipulation processes such as broadband frequency conversion with unit efficiency. Finally, I will discuss how quantum descriptions of the electromagnetic fields impose fundamental efficiency limits and lay out a pathway for the generation and manipulation of quantum light with time-metamaterials.
