Optimization of /spl Lambda/-shaped molecules for second harmonic generation in media with nonpolar alignment

Summary form only given. Considerable effort has been directed towards creating organic nonlinear materials for second harmonic generation electro-optic control that would implement the non-vector irreducible components of the first hyperpolarizability tensor. In particular, the second-rank tensor component can give rise to macroscopic nonlinearity /spl chi//sup (2)/ in systems having chiral nonpolar symmetry of the bulk, such as D/sub /spl infin// or D/sub 2/. These types of alignment can be achieved in uniaxially or biaxially stretched chiral polymers, or in various uniaxial (N, SmA) and biaxial (SmC) liquid crystal phases. To make an efficient frequency conversion material, one has to optimize both the molecular response of the active chromophore and the macroscopic alignment scheme.