Studies of organic-inorganic hydride materials for nonlinear optical applications

Nonlinear optical (NLO) crystals, due to their nonlinear properties, have been found to have enormous applications in frequency conversion, image processing, data storage, fiber optic communication, etc. Recently, variety of semi-organic crystals for nonlinear optics applications have been developed, among them the donor-acceptor molecule are found to have definite edge over others as they display special features of interest, such as nitroanilines have inherently large second-order microscopic polarizabilities and they seem to be very good candidates for nonlinear optical materials. As far as we know, there has been only one attempt to systematically explore the second-order nonlinear response of clusters of these chromophores to relate the resulting intermolecular interactions to the quadratic hyperpolarizabilities, these molecular interactions being of the dipole-dipole type. A potentially useful organic-inorganic nonlinear optical aqueous solutions of p-Nitroanilinium with different anions (nitrate, sulphate and perchlorate) has been synthesized at room temperature by slow solvent evaporation method. We will report the measurement of absorption and nonlinear third-order optical susceptibilities of p-Nitroanilinium doped with different anions. Measurements were performed in solutions using transmission experiment and the degenerate four wave mixing technique (DFWM) at 532 nm. The value obtained for the best compound in terms of ( chi^<3> ) is the same order of larger than the value of CS₂, which is a reference material. Third order nonlinear optical susceptibility of the studied compounds was evaluated using third harmonic generation (THG) set up at 1064 nm. The measurements were performed on thin films.