Design, Synthesis and Characterization of Novel Nonlinear Optical Materials
Annual rept. 1 Apr 1993-31 Mar 1994
STATE UNIV OF NEW YORK AT BUFFALO DEPT OF CHEMISTRY
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This project consisted of four tasks each dealing with a different class of nonlinear optical materials. Task U Second-Order material. During the past year we used theoretical and experimental studies to develop a new class of materials in which a commonly used electron donor chromophore was replaced by a thiophene ring. To efficiently pole a second-order ionic chromophore, the use of a bulky counter-ion in order to reduce ionic conductivity was demonstrated. We also investigated the imagineary part of X2 by electro-absorption. Task II Third-Order Materials. We synthesized a group of phosphoylides which contain a polarizable P atom. Their X3 behavior were experimentally investigated using femtosecond Kerr gate. Using our new method of optically heterodyned and phase-tuned Kerr gate method, we investigated both the signs and the magnitudes of the real and the imaginary components of X3. We showed that in the case of one-photon saturation, the sign of imaginary part is negative, while for two-photon absorption, this sign is positive. A very efficient two-photon induced fluorescence was also found for another nonlinear chromophore, diethylaminonitrostyrene, in the crystalline form. Task III photorefractive polymeric composites.