Experimental Investigation of Optical Nonlinearities in Conjugated Polymers.
Final rept. Sep 93-Sep 96,
UNIVERSITY OF CENTRAL FLORIDA ORLANDO
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This AASERTT award has allowed us to extend our research into 1 the third order nonlinearities of conjugated polymers and 2 their applications in nonlinear optics. THG Spectroscopy of Polymers - The real and imaginary parts of the third order susceptibility chi33 omega were measured by Third Harmonic Generation THG over broad spectral ranges with the fundamental wavelength varying from 700 to 2200 nm. Fitting the resulting spectra to 2, 3 or 4 level models, i.e. 2, 3 or 4 electronic states participating in the transitions, identified the number of important states and the oscillator strengths for transitions between them. Nonlinear Optics of PTS. Measurement is made of the frequency dependence of complex susceptibilities. At high incident intensities, of order of a few GWcm2, effectively an intensity dependent susceptibility was found in the immediate vicinity of the strong two photon transition from the lA sub g to the mA sub g state. Our analysis of the functional dependence on the intensity shows that saturation of the population in the two photon state was responsible. The corresponding separation was found to be 2 GWcm2.