applied math seminar
Title: PT-Symmetric Kagome Photonic Lattices and Localization
We consider a complex photonic lattice by placing parity-time or PT-symmetric dimers at the Kagome lattice points. This lattice is a two-dimensional network of corner-sharing triangles. Each dimer represents a pair of strongly coupled waveguides. The frustrated coupling between waveguide modes results in a dispersionless flat band comprising spatially localized modes. For a balanced arrangement of gain and loss on each dimer, up to a critical value of the gain/loss parameter the system exhibits a PT-symmetric phase. The beam evolution in the waveguide array leads to an oscillatory rotation of the optical power along the propagation distance. We observe long-lived local chiral structures that originate from the nearly flat bands of the Kagome structure when the lattice is subject to a narrow beam excitation. Next, we study nonlinear optical beam propagation in this set up and show that inclusion of Kerr-type nonlinearity leads to novel optical solitons. Such photonic lattices are likely to have potential applications in optical beam engineering, image processing and active metamaterials. (Work done in collaboration with Gia-Wei Chern, University of Virginia).
Brief bio: Avadh Saxena is Group Leader of the Condensed Matter and Complex Systems group (T-4) at Los Alamos National Lab, New Mexico, USA, where he has been since 1990. He is also an affiliate of the Center for Nonlinear Studies at Los Alamos. His main research interests include phase transitions, optical, electronic, vibrational, transport and magnetic properties of functional materials, device physics, soft condensed matter, geometry, topology and nonlinear phenomena. He is an Affiliate Professor at the Royal Institute of Technology (KTH), Stockholm, Sweden and holds adjunct professor positions at the University of Barcelona, Spain, Virginia Tech and the University of Arizona, Tucson. He is Scientific Advisor to National Institute for Materials Science (NIMS), Tsukuba, Japan. He is a Fellow of Los Alamos National Lab, a Fellow of the American Physical Society (APS), and a member of the Sigma Xi Scientific Research Society and APS. Contact him at: email@example.com
Contact Name: Pavel Lushnikov