EventŞahin K. Özdemir

Non-Hermiticity and Parity-Time Symmetry in Optics

Recent years have seen a tremendous progress in the theory and experimental implementations of concepts rooted in non-Hermitian physics. This progress has led to a host of new intriguing results in optics with promising potential applications. One of the most notable property of non-Hermitian systems is the emergence of non-Hermitian degeneracies known as exceptional points (EPs) where complex eigenvalues and the corresponding eigenstates of the system coalesce. The presence of an EP affects the system significantly, leading to nontrivial physics with interesting features. Whispering-gallery-mode (WGM) microresonators have emerged as excellent platforms for these studies because they represent open physical systems and are characterized by non-Hermitian Hamiltonians. In this talk, after briefly reviewing the related physics and the applications that have been developed in the past few years, I will present the progress in our experimental and theoretical studies towards a better understanding of optical processes (e.g.,, sensing, nonreciprocity, nonlinear interactions, etc) and optomechanical interactions (e.g., phonon lasers, metrology, etc) at EPs for realizing photonic and phononic devices with novel functionalities. I will end the talk with a summary of other interesting phenomena we study with WGM resonators and discuss some of the opportunities and challenges in photonics research, in particular within the framework of non-Hermitian optics.

Biography. Dr. Özdemir is an Assoc. Prof. of Engineering Science and Mechanics at Pennsylvania State University. Before joining Penn State, he was with Washington University in St. Louis (2009-2017). He received his BSc (1992) and MSc (1995) from the Middle East Technical University, Turkey, and PhD (2000) from Shizuoka University, Japan, all in electrical and electronics engineering. During 2000-2009 he was with The Graduate University for Advanced Studies and then with Osaka University working as project leader and senior scientist for various research programs of Japan Science and Technology Agency (JST) on photonic quantum information processing. Dr Özdemir has authored over 130 peer-reviewed papers on topics ranging from quantum photonics, PT-symmetric optics, and plasmonics to microcavities, optical sensing and optomechanics. He is a member of OSA and a senior member of IEEE.