Speaker: Professor Sergei A.Tretyakov, Aalto University

Time: 14:00 to 17:00, October 12, 2026

Place: B1-c101

Abstract

In this presentation we will discuss recent research on non-local and time-varying metasurfaces that can be configured for various functionalities by changing bulk components (variable capacitors, for example) in their meta-atoms. The introduced solutions allow full reconfigurability in geometrically fixed platforms. In particular, we will show possibilities to realize theoretically perfect all-angle scanning reflectors, leaky-wave antennas, absorbers, multifunctional metasurfaces. Importantly, many of these solutions can exhibit even superdirective properties at all scan angles. For example, in the absorbing regime these panels can absorb more power than is incident on their surfaces. Furthermore, we will discuss various functionalities that can be realized using time-modulated metasurfaces, such as amplification, conversion to surface waves, “freezing” of waves, nonreciprocal effects. Finally, we will discuss  possible future research directions towards creation of autonomous programmable electromagnetic materials.

Biography

Sergei A. Tretyakov received the Dipl. Engineer-Physicist, the Candidate of Sciences (PhD), and the Doctor of Sciences degrees (all in radiophysics) from the St. Petersburg State Technical University (Russia), in 1980, 1987, and 1995, respectively. From 1980 to 2000 he was with the Radiophysics Department of the St. Petersburg State Technical University. Presently, he is professor (emeritus) of radio science at the Department of Electronics and Nanoengineering, Aalto University, Finland. His main scientific interests are electromagnetic field theory, complex media electromagnetics, metamaterials, and microwave engineering. He has authored or co-authored six research monographs, tutorial books, and more than 390 journal papers. Prof. Tretyakov served as President of the Virtual Institute for Artificial Electromagnetic Materials and Metamaterials (”Metamorphose VI”), as General Chair of the International Congress Series on Advanced Electromagnetic Materials in Microwaves and Optics (Metamaterials), from 2007 to 2013, and as Chairman of the St. Petersburg IEEE ED/MTT/AP Chapter from 1995 to 1998. He is a Life Fellow of the IEEE.