PT-Symmetric Kagome Lattices and Localization
主 题: PT-Symmetric Kagome Lattices and Localization
报告人: Avadh Saxena (Los Alamos National Lab)
时 间: 2017-06-19 09:00-10:00
地 点: 理科一号楼1479室
Abstract: We consider a complex photonic lattice by placing 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. We observe local chiral structures with a narrow beam excitation. We also study nonlinearity and disorder in this set up. (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 and nonlinear phenomena. He 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: avadh@lanl.gov.
