On Friday 07.06.2019, Prof. Filippo Capolino (University of California, Irvine, USA) visited our Electromagnetic Systems Group and gave an interesting guest lecture entitled “Theory and applications of exceptional points of degeneracy in electromagnetics”.
Professor Filippo Capolino
University of California, Irvine, USA
Theory and applications of exceptional points of degeneracy in electromagnetics
An exceptional point of degeneracy (EPD) is a point in the eigenmodes spectrum of a system at which at least two eigenmodes coalesce in both their eigenvalues and eigenvectors, where the order of the EPD is determined by the number of coalescing eigenmodes. We provide an algebraic theory in a Hamiltonian-like formalism to describe such degeneracy conditions and their physical properties. We will present a general framework to obtain this kind of degeneracy conditions related to periodicity, loss, gain, and time modulation of a system. We then explore their applications as oscillators, sensors, etc. In particular we will investigate the lasing threshold of oscillators operating near an EPD. We investigate the scaling of the lasing threshold with length of the cavity formed by coupled resonators optical waveguide (CROW) modified in such a way that can support various orders of EPDs. The modified CROW consists of a chain of coupled ring resonators that are side-coupled to a straight waveguide.
Biography
Filippo Capolino received the Laurea (cum laude) and the Ph.D. degrees in electrical engineering from the University of Florence, Italy, in 1993 and 1997, respectively. He is currently a Professor with the Department of Electrical Engineering and Computer Science of the University of California, Irvine, CA, USA. Previously he has been an Assistant Professor with the Department of Information Engineering of the University of Siena, Italy till 2002. From 1997 to 1999, he was a Fulbright and then a Postdoctoral Fellow with the Department of Aerospace and Mechanical Engineering, Boston University, MA, USA. From 2000 to 2001, part of 2005 and in 2006, he was a Research Assistant Visiting Professor with the Department of Electrical and Computer Engineering, University of Houston, TX, USA. He has been a Visiting Professor at the Fresnel Institute, Marseille, France (2003) and at the Centre de Recherche Paul Pascal, Bordeaux, France (2010). His current research interests include metamaterials and their applications, traveling wave tubes, antennas, wireless systems, sensors in both microwave and optical ranges, plasmonics, nano optics, spectroscopy, microscopy, and applied electromagnetics in general.
Dr. Capolino received the R. W. P. King Prize Paper Award from the IEEE Antennas and Propagation Society for the Best Paper of the Year 2000, by an author under 36. He was the founder and the EU Coordinator of the EU Doctoral Programs on Metamaterials from 2004 to 2009. He is the Editor of the Metamaterials Handbook (Boca Raton, FL, USA: CRC Press, 2009).