Κατάλογος Εκδηλώσεων

Speaker: 

Associate Professor Constantinos Valagiannopoulos (Nazarbayev University, Kazakhstan)

Title:

Inverse Design for Basic Photonic Setups

Abstract:

Research on inverse design of photonic architectures is currently experiencing an upsurge of scientific and funding interest. It includes the determination of the structure/texture combination producing a desired output and the detection of limits in the performance for certain classes of particles or devices. A systematic approach for inverse design of basic photonic architectures will be presented  under certain constraints, the most significant of which is the availability of the employed media. The basic philosophy of the followed technique is to “entrap” the maxima into parametric boxes by rejecting the boundary extrema and performing frequency hopping. Characteristic cases of core-shell nanoparticles and their collective operation in metasurfaces layout will be analyzed while maxima of their performance for each combination of materials will be reported. The optimal operation of the considered configurations concerns various objectives like maximal absorption and scattering, anomalous reflection and refraction or highly selective frequency response. Such features are vital for numerous practical applications spanning from ultra-sharp switching and sensing to efficient beam steering and power accumulation. Finally, certain examples of how the same principles for inverse design are translated into nonlinear active systems and quantum setups will be given.

Bio:

Constantinos Valagiannopoulos (IEEE M’12, SM’16) was born in Athens, Greece, in 1982. He received the Dipl. Eng. (Hons.) degree in Electrical Engineering from the National Technical University of Athens, Greece, in 2004, and the Ph.D. degree on Electromagnetic Theory in 2009 from the same Institute. Between 2010 and 2014, he was a Postdoctoral Researcher in the Group of Theoretical and Applied Electromagnetics of Complex Media at Department of Electronics and Nanoengineering, Aalto University, Finland (advisor: Sergei Tretyakov). During the academic year 2014–2015, he was with the Laboratory of Metamaterials and Plasmonics at Department of Electrical and Computer Engineering, University of Texas at Austin, USA (advisor: Andrea Al). From 2015, he is with Nazarbayev University (NU), Kazakhstan, as an Assistant and from 2018 as an Associate Professor in Department of Physics. Meanwhile, he has been a visiting Assistant Professor at University of Southampton (Pavlos Lagoudakis group) and a visiting Scholar at Harvard University (Efthimios Kaxiras group). He currently leads the Metamaterials Modeling and Design Group at NU performing research on the forward and inverse design of photonic devices manipulating the light. He has authored or coauthored more than 90 works published at international refereed scientific journals and presented numerous reports in scientific conferences. He is currently participating as Principal Investigator (PI) or co-PI in the successful execution of national and international winning research grants with total annual budget more than 450K USD. Dr. Valagiannopoulos received the inaugural 2015 JOPT Research Excellence Award for his work: “Perfect absorption in graphene multilayers” and is a Senior Member of IEEE and OSA. He also received the International Chorafas Prize for the Best Doctoral Thesis in 2008, and the Academy of Finland Postdoctoral Grant for 2012–2015.