Modern communication systems are characterized by increasing demands in terms of various metrics, including low loss, power efficiency, compact size and integrability. Many of these requirements can hardly be achieved through conventional technology and require the development of new techniques. In this talk, I will show how it is possible to address these problems and design electromagnetic devices with unprecedented characteristics by using time modulation, nonlinear effects and gain. I will begin my talk by discussing how time modulation can be used to achieve magnetless nonreciprocity in various frequency ranges, with applications in the design of circulators for full-duplex communication systems, isolators for protection of sources, nonreciprocal metasurfaces for advanced wave manipulation, and topological insulators that are immune to disorder. Next, I will show how by combining electromagnetic resonances with nonlinear effects, it is possible to design interesting optical functionalities, such as isolators without any form of biasing, and power limiters. I will also present the unique characteristics of structures with balanced gain and loss, focusing on the unprecedented functionalities that such structures can provide, including broadband cloaking and negative refraction without using resonant metamaterials. I will show how all these concepts are aligned with the recent advances in the fabrication of efficient nanodevices at microwave, THz and optical frequencies, and provide a general vision for a new gen
Dimitrios L. Sounas received the Ph.D. degree in Electrical and Computer Engineering with the highest honors from the Aristotle University of Thessaloniki, Greece, in 2009. Between 2010 and 2015, he was a Post-Doctoral Fellow, first at Polytechnique Montreal and later in The University of Texas at Austin. Since 2015, he has been a Research Scientist in The University of Texas at Austin. His research interests span over a broad range of areas, including electromagnetics, plasmonics, optics and acoustics, with a particular emphasis on the design of nonreciprocal, nonlinear and active devices. He has been the author or the co-author of 48 journal papers, 90 conference papers, 2 book chapters and 4 patents, among which papers in highly selective journals, including Science, Nature Physics, Nature Communications, Physical Review Letters, and IEEE Transactions. He has made major contributions in the area of magnetless nonreciprocal components, which have attracted significant interest from the industry and the military for inclusion in the next-generation wireless communication systems. His work has been covered by the general media and resulted in the foundation of a startup company in Austin, specializing in the design of angular-momentum circulators for RF and acoustical systems.