7 October 1996 Z-scan measurements on substituted thiophene oligomers
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The nonlinear optical properties of a series of substituted thiophene oligomers have been investigated using the Z-scan technique. As the length of the thiophene increases from the monomer to an oligomer containing nine thiophene units, the absorption spectrum shifts to longer wavelength. This shift in wavelength moves the absorption band into resonance with the laser wavelength and the nonlinear optical properties of these materials change. In the samples where there is no linear absorption at the laser wavelength, the nonlinear absorption appears to originate from a two-photon absorption process. The nonlinear refraction observed is dominated by the contributions of the solvent. In the samples where there is linear absorption at the laser wavelength, several competing mechanisms appear to be responsible for the nonlinear response observed. At low laser irradiance, saturable absorption is observed. As the laser irradiance is increased, a decrease in the transmitted energy is observed. The nonlinear refraction in these materials is now large and negative.
© (1996) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Paul A. Fleitz, Paul A. Fleitz, Richard L. Sutherland, Richard L. Sutherland, Nansheng Tang, Nansheng Tang, W. Li, W. Li, Luping Yu, Luping Yu, "Z-scan measurements on substituted thiophene oligomers", Proc. SPIE 2853, Nonlinear Optical Liquids, (7 October 1996); doi: 10.1117/12.253478; https://doi.org/10.1117/12.253478

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