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** KOÇ UNIVERSITY PHYSICS SEMINAR**

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**Speaker ** : Ali Mostafazadeh, Koç University

**Title ** : Broadband perfect invisibility in two dimensions

**Date ** : April 27, 2017 Thursday

**Time** : 4:00 P.M.

**Cookie & Tea** : SCI 103 3:45 P.M.

**Place** : SCI 103

**Abstract:**

Achieving broadband invisibility has been a great challenge since the early days of the formulation of scattering theory. During the past two decades there have appeared a number of ingenious but complicated schemes to achieve broadband invisibility. These makes use of metamaterials or especially designed anisotropic media. In this talk I will outline a much simpler solution to this problem that achieves perfect invisibility in a frequency band [0,f], where f is a free parameter of the construction. This solution follows as a simple outcome of a recently proposed dynamical formulation of scattering theory. I will therefore offer an elementary discussion of this formulation, use it to derive a simple mathematical condition for perfect invisibility in two dimensions, and examine its optical implementations. In particular, I discuss its application in constructing an infinite class of isotropic nonmagnetic optical slab systems that are invisible for both TE and TM waves with a frequency in the range [0,f]. These results do not rely on any approximation scheme or the use of metamaterials, and admit a straightforward extension to three dimensions.

Note: This is a joint work with Farhang Loran of Isfahan University of Technology.

**Bio:**

Ali Mostafazadeh was born in 1965 in Tabriz, Iran. He received his BS degrees in physics and mathematics from Boğaziçi University in 1989 and his Ph.D. in physics from the University of Texas at Austin in 1994 (under the supervision of Bryce DeWitt.). He held a Killam Postdoctoral position at the University of Alberta before joining Koç University in 1997. His areas of interest include geometric and topological aspects of quantum mechanics, supersymmetry and its generalizations, quantum cosmology, non-Hermitian operators, mathematical optics, and scattering theory. He is the author of 3 books and over 130 research publications, an elected principal member of the Turkish Academy of Sciences since 2007, and a recipient of TÜBİTAK Science Award the same year.