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 time-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.
Biography:
Dr Emanuele Galiffi is a Research Scientist at the Advanced Science Research Center of the City University of New York, in the group of Prof. Andrea Alu. Originally from Alghero, Italy, Dr Galiffi received his Bachelor and Master's degree in Physics in 2016 from Imperial College London, where he carried out his doctoral studies, working on transformation optics, plasmonics and space-time metamaterials, under the supervision of Prof. Sir John Pendry and Dr Paloma A. Huidobro. For his doctoral research, he was awarded the Johnson Matthew PhD Thesis Prize and the 2020 EPSRC Doctoral Prize Fellowship. Soon after, he was awarded a Junior Fellowship of the Simons Society of Fellows, with which he joined in 2021 the group of Prof. Andrea Alù, where his research focused on time-varying metamaterials and on polaritonic phenomena in low-symmetry crystals and metasurfaces. He has co-authored more than 40 peer-reviewed articles on several high-profile journals, including Science, Nature Physics, Physical Review X, Physical Review Letters, Nature Communications and PNAS, and his work has been cited more than 2000 times.
