Azo-azulene derivatives for nonlinear optical applications

Organic materials are of high interest and are widely used for the development of new powerful and low dimensional technologies. They exhibit several advantages with respect to inorganic compounds such as large cubic and quadratic optical nonlinearities, flexibility, easy manufacturing and so on. Among them, some present abilities for photonic or nonlinear optical applications. Intensive researches have been performed these latest decades to synthesize highly efficient and optically active molecules because of the miniaturization of optoelectronic devices. Azo-azulene derivatives are an interesting class of organic molecules for potential applications in optoelectronics and optical data storage due to their polyfunctional properties. We discuss second and third order nonlinear optical properties of a series of azo-azulene compounds in solid state. Thin films were prepared by incorporating these molecules in a polymethylmetacrylate (PMMA) matrix and were investigated. Moreover, potential usage of these guest-host systems for optical data storage is also discussed

Investigation of NLO properties of azo-azulene derivatives for nonlinear optical applications

Date du colloque&nbsp;: 09/2008</p

Noncommutative solitons on Kahler manifolds

We construct a new class of scalar noncommutative multi-solitons on an arbitrary Kahler manifold by using Berezin's geometric approach to quantization and its generalization to deformation quantization. We analyze the stability condition which arises from the leading 1/hbar correction to the soliton energy and for homogeneous Kahler manifolds obtain that the stable solitons are given in terms of generalized coherent states. We apply this general formalism to a number of examples, which include the sphere, hyperbolic plane, torus and general symmetric bounded domains. As a general feature we notice that on homogeneous manifolds of positive curvature, solitons tend to attract each other, while if the curvature is negative they will repel each other. Applications of these results are discussed.Comment: 26 pages, 3 figures, harvmac; references adde

Postcoloniality and forced migration: mobility, control, agency

This powerful book explicates the many ways in which colonial encounters continue to shape forced migration, ever evolving with times and various geographical contexts. Bringing historians, political scientists, sociologists, anthropologists and criminologists together, the book presents examples of forced migration events and politics ranging from the 18th century to the practices and geopolitics of the present day. These case studies, covering Europe, Africa, North America, Asia and South America, are then put in dialogue with each other to propose new theoretical and real-world agendas for the field. As the pervasive legacies of colonialism continue to shape global politics, this unprecedented book moves beyond critique, ahistoricity and Eurocentrism in refugee and forced migration studies and establishes postcoloniality and forced migration as an important field of migration research