Speaker

Dimitrios Sounas, Assistant Professor, Wayne State University

Abstract

Analog computing has emerged as a promising paradigm for overcoming the limitations of digital computers. Waves are particularly suitable for implementation of linear operations, i.e., matrix algebra, which in many cases are the most demanding operations in computing systems. In this context, various approaches have been investigated, including nonlocal metasurfaces, inversely designed metamaterials, diffractive metasurfaces, and networks of Mach-Zehnder interferometers. Nonlocal metasurfaces offer small size and high efficiency, but are limited to simple operations, like spatial differentiation. Diffractive metasurfaces can implement general operations, but require stacking of metasurfaces at precisely chosen distances, leading to increased sensitivity to fabrication imperfections. Inversely designed metamaterials and networks of Mach-Zehnder interferometers can also implement general operations, but only in guided-wave scenarios.

In this talk, we will present an overview of the current approaches of analog computing with waves and related applications. We will specifically focus on a new approach introduced in our group based on discrete space metamaterials, which can implement advanced imaging operations, like edge detection and image compression. Our approach is inspired by digital filters in electronics, and consists of realizing desired operations on discretized waves in space through arrays of optical antennas. By using this technique, we present the first ever optical implementation of image compression for waves in free space and show how our structure can substantially reduce the information entropy of an incident wave, reducing the amount of information required to store or transmit the wave. The proposed approach opens a new direction in analog computing with waves and can inspire the development of a new generation of imaging systems with high efficiency and high speed.

Biography

Dimitrios Sounas is an Assistant Professor at the ECE Department at Wayne State University. He has received his Ph.D. degree in Electrical and Computer Engineering from the Aristotle University of Thessaloniki, Greece, in 2009. From 2010-2018 he has been a postdoctoral fellow and a research scientist at Polytechnique Montreal and the University of Texas at Austin.

He has made major contributions in magnet-less nonreciprocal devices with applications in full-duplex systems and radars. He has contributed to the founding of Silicon Audio RF Circulator, Austin, TX, USA, specializing in the design of angular-momentum circulators for RF and acoustical systems. He has authored or co-authored over 100 papers in peer-reviewed journals, including Science and various Nature journals. He has more than 150 conference abstracts, 6 patents, and more than 8,000 citations. His current research focuses on time-modulated and topological metamaterials, optical signal processing, and inverse design, and is funded by the Department of Defense.

Dimitrios is a Senior Member of IEEE and the recipient of the 2020 EurAAP Leopold B. Felsen Award for Excellence in Electrodynamics. He has chaired and organized various sessions in international symposia. He is an Associate Editor for the IEEE Transactions on Antennas and Propagation and a reviewer for more than 20 engineering and physics journals.