Organometallic chromophores and polymers that feature heavy metals exhibit strong non-linear optical response arising from several mechanisms, including two-photon absorption and excited state absorption from long lived triplet excited states. The talk will overview work focused on synthesis and optical characterization of chromophores and materials.
The success of synthesizing monolayer protected clusters (MPCs) in the condensed phase has allowed scientists to probe their unique quantum confined properties directly. In this talk our recent results showing the unique optical properties of these gold and silver metal clusters will be presented.
We performed a detailed study on the triplet state absorption properties of seven organometallic complexes. The singlet-triplet conversion quantum yield was obtained based on a 6-level electronic model. We observed triplet yields of less than unity, contrary to previous reports for this class of compounds.
We investigate the nonlinear optical properties of a series of two-photon absorbing chromophores in the femtosecond regime using both two-photon induced fluorescence spectroscopy and the Z-scan technique. We apply a simplified sum-over-states model to the experimental data to predict nonlinear refraction.
We studied the effects of bromine substitution on the nonlinear absorption properties of aza-dipyrromethene dyes. Nonlinear absorption is measured at wavelengths of 1200, 1500, and 1700nm. At 1200nm, excited-state absorption due to two-photon excitation appears, and it is more pronounced in the brominated polymethine cyanine.
The study presented here demonstrates the application of a steroid, lithocholic acid, along with β-estradiol and cholesterol, to long lifetime nonlinear optical materials. These glasses have been shown to minimize oxygen diffusion and reduce nonradiative decay from excited states, thus extending the effective phosphorescence lifetime.