9307182 Zhang A study of optical nonlinearities of an unusual class of nonlinear organic crystals is proposed. The principal investigator proposes to use this crystal for optoelectronic characterization of high- speed integrated circuits. This nonlinear organic crystal, which is synthesized at GE and recrystallized at Rensselaer, shows extremely high nonlinearity. These organic crystals emit the most intense optically induced terahertz radiated field among all of the natural non-externally biased materials we know. A plan to measure the second order nonlinear susceptibility of these organic crystals by using a newly developed ultrafast optoelectronic technique is proposed. The ratio of independent nonvanishing susceptibility tensor elements by analyzing the phase and the amplitude of subpicosecond optical rectification radiation from these crystals will be identified. The physics origin of THz persistent oscillation in their optical rectification after femtosecond optical excitation will be explored. This organic crystal will be integrated into an electro-optic sampling system for noncontact ejection and detection of terahertz bandwidth electromagnetic signals in ultrahigh speed integrated circuits. The proposed work is expected to have a substantial impact on the physical understanding of these nonlinear organic crystals and is also expected to provide important applications which will ensue for the optoelectronic characterization of these crystals. ***
