In this lecture, the speaker will review recent results on metamaterials consisting of high-contrast subwavelength resonators whose material parameters oscillate periodically in time. His main focus is on developing a capacitance matrix characterization of the band structure, which generalizes previous recent works on static subwavelength metamaterials. This discrete characterization provides both theoretical insight and efficient numerical methods to compute the dispersion relationships of time-dependent structures. Several structures exhibiting interesting subwavelength manipulation properties will be exemplified.
As will be shown in this lecture, the time-modulation causes a folding of the band structure of the material, which may induce degenerate points. By breaking time-reversal symmetry, these degeneracies may induce exceptional points, k-gaps, or open into non-symmetric, unidirectional band gaps. Topological properties of time-dependent structures will be also discussed.
About the speaker
Prof. Habib AMMARI received his PhD in Applied Mathematics from the Ecole Polytechnique in 1995. He was a researcher at Ecole Polytechnique from 1995 to 1997, and at the French National Center for Scientific Research (CNRS) from 1997 to 2006. He became a Director of Research at the CNRS and was affiliated with Ecole Polytechnique from 2006 to 2010 and with Ecole Normale Superieure from 2010 to 2015 respectively. He then moved to the ETH Zurich and is currently the Professor of Applied Mathematics.
Prof. Ammari’s research focuses on wave propagation phenomena in complex media, mathematical modelling in photonics and phononics, and mathematical biomedical imaging. He has published more than two hundred research papers, eight high profile research-oriented books and edited eight books on contemporary issues in applied mathematics.
Prof. Ammari has been named a Fellow of the American Mathematical Society since 2022. He is also a Member of the Academia Europaea (2021), the European Academy of Sciences (2018) and the Tunisian Academy of Sciences, Letters and Arts (2015). He is the recipient of the 2015 Khwarizmi International Award in Basic Sciences and the 2013 Kuwait Prize in Basic Sciences.
For Attendees' Attention:
This talk will be held online via Zoom. To attend, please join the Zoom meeting at https://hkust.zoom.us/j/96225734268 (Meeting ID: 962 2573 4268 / Passcode: 20220713).
About the program
For more information, please refer to the program website at https://iasprogram.hkust.edu.hk/inverseproblems/.