ORGANIC MATERIALS FOR NONLINEAR OPTICS - THE 2D APPROACH

Conventional organic molecules for applications in second-order non-li near optics are donor-acceptor substituted pi systems that show only o ne intense charge-transfer (CT) transition. Thus, only a single elemen t of the second-order polarizability tensor, beta, is significant in t hese one-dimensional systems. The advantages and optimization strategi es for two new classes of molecules with multiple CT transitions and t wo-dimensional second-order polarizability are reviewed. These are don or-acceptor substituted pi systems that lack a dipole and have a molec ular symmetry of Cg or higher, and dipolar molecules of symmetry C-2v. A basic introduction to the field is also given.