MOLECULAR-CRYSTALS AND POLYMERS FOR NONLINEAR OPTICS

We present new experimental results on second-harmonic generation in h ighly conjugated organic molecules and molecular crystals recently dev eloped in our group, as well as on electro-optic effects in thin-film polymers. A large value of the molecular hyperpolarizability of a new hydrazone-type molecule crystallizing in a noncentrosymmetric point gr oup is reported. Large nonlinear optical coefficients of up to 840+/-2 00 pm/V were measured in crystals of 4'-dimethylamino-N-methyl-4-stilb azolium tosylate (DAST). The new experimental results are compared wit h theoretical calculations of limiting values of nonlinear optical coe fficients. Computer modeling of crystal structures shows good agreemen t with experimental results. Measurements on electro-optic polymers wi th high thermal stability are presented.