2017-3-21, Lecture : A stochastic methodology for the design of random meta-materials

Speaker:Ivi C. Tsantili
Title:A stochastic methodology for the design of random meta-materials
Abstract:We will present a stochastic computational methodology for generating and optimizing random meta-material configurations with non-overlapping geometric constraints subject to various types of covariances and distributions characterizing the randomness of the meta-material configurations [1]. The methodology developed consists of three main components: (1) A deterministic solver for electromagnetic scattering from multiple objects. (2) The Karhunen-Loève (K-L) expansion to represent the correlated configurations of the scattering objects. (3) The Multi-element probabilistic collocation method (ME-PCM) to provide flexibility in achieving desired distributions of the meta-materials. We employ random fields from the Spartan family which are models inspired by statistical physics, include covariance functions with damped oscillatory behavior and for which an analytic expression for the K-L expansion has been recently obtained [2]. We construct continuous (or refined discrete) random fields which we then project onto discrete locations to obtain non-overlapping scattering objects or random layers. The algorithm is applied to study light propagation through random layered heterojunctions, comprised of layers with different dielectric constants. We compute the transmission and reflection coefficients in terms of the transfer and scattering matrix formulation. We investigate the effect of random correlation of the layers' positions. We found that greater transmission, compared to the uniformly spaced layers, can be achieved for a layer configuration with an oscillatory spacing profile.

Introduction:Ivi C. Tsantili, Post-Doctoral Research Fellow,Algorithms Division, Beijing Computational Science Research Center, Beijing, China.  She got her PhD degree in the field of Stochastic Analysis of Dynamical Systems in 2013, in National Technical University of Athens (NTUA), School of Naval Architecture and Marine Engineering (SNAME), Athens, Greece, and then she worked with Prof. Dionisios T. Hristopulos as a Post-Doctoral Research Fellow in Technical University of Crete (TUC), School of Mineral Resources Engineering, Geostatistics. From January 2016, Ivi joined to Beijing Computational Science Research Center, Algorithms Division as a Post-Doctoral Research Fellow and worked with Prof. Wei Cai and Prof. Karniadakis. She has published eight peer-reviewed papers.