Who
Dr. Theodoros Koutserimpas
When
22 July 2025, 11:00 Athens time, Science Building 145Π42
Title
Waves in Time-Varying Media, Nonlinear Optical Phenomena and the Principle of Causality
Abstract
In the first part of this talk, I will discuss the\ incorporation of time as an extra dimension in electromagnetic and optical systems which can introduce new degrees of freedom for wave manipulation, offering exciting opportunities to reshape our understanding and control of waves. In particular, I will present my research on the theoretical and computational foundations of wave propagation in such media. I will begin by examining how temporal modulation enables parametric amplification and describe its deep connections to non-Hermitian photonics and operator symmetries. I will also discuss dynamic amplification mechanisms that arise from Doppler-shift effects. In the second part of the talk, I will address how the fundamental principle of causality constrains both linear and nonlinear optical responses. I will highlight recent results that extend classical sum rules, such as the equivalence between the f-sum rule and the Thomas-Reiche-Kuhn (TRK) sum rule, and explore their implications for establishing and approaching theoretical bounds on linear and nonlinear optical processes. These insights deepen our understanding of light-matter interactions while informing the design of materials and devices that push the limits of performance.
About the Speaker
Theodoros T. Koutserimpas received his Diploma in Electrical and Computer Engineering from the National Technical University of Athens in 2017 and his Ph.D. in Electrical Engineering from EPFL in 2021. His research interests include electromagnetic theory, optics, computational electromagnetics, acoustics, applied quantum mechanics, and more broadly the analytical and numerical modeling of wave phenomena. He held a postdoctoral position at Princeton University and is currently a Postdoctoral Research Associate at Cornell University. He is a recipient of the Swiss National Science Foundation Postdoc Mobility Fellowship and the “Stamatis G. Mantzavinos” Postdoctoral Scholarship from the Bodossaki Foundation. He is a member of IEEE, OPTICA, APS, and the Technical Chamber of Greece.
