Description

2011/01/28, Prof. A. Sadreev (Institute of Physics, Krasnoyarsk, Russia)

Place:  Sala de Seminarios del Departamento de Física Teórica e Historia de la Ciencia
Time: 11:30h.
Title: Light localization in photonic crystal waveguide coupled to
Kerr defects

Abstract
von Neumann and Wigner in 1929 claimed that Schroedinger equation could possess localized solutions in the form of bound states in continuum (BSC). These solutions   appear for a special class of potentials and correspond to isolated eigenvalues embedded in the continuum of positive energy states. This result was regarded for a long time as a mathematical curiosity till Capasso observed the BSC in superlattices. Examples of the BSC can be more easily found if one goes beyond the one-dimensional Schroedinger equation, for example in open two-dimensional quantum dots and photonic crystal Fabry-Perot resonators. However, there the BSC might exist only in a narrow range of parameters. We show that using nonlinear (Kerr) elements in photonic crystal waveguides opens the venue to achieve robust self-consistent BSC. As a result, light localization around these elements gives rise to new types of resonances. Moreover we show that nonlinearity breaks the system symmetry even if elements are arranged  symmetrically.