Effective stimulated emission and excited state absorption measurements in the phenylene-vinylene oligomer (1,4-bis-(alpha-cyanostyryl)-2,5-dimethoxybenzene))

The pump probe technique was used to measure the effective stimulated emission and excited state absorption cross-sections of the phenylene-vinylene oligomer (1,4-bis-(alpha-cyanostyryl)-2,5-dimethoxybenzene) dissolved in toluene for different probe wavelengths. The effective stimulated emission cross-section was calculated from sigma(SE-eff) = sigma(SE) - sigma(ESA) and found to be positive. The possible laser tuning ranges have been determined. The spectral and temporal behavior of the optical transitions were investigated. The dynamics of these optical transitions permitted direct measurements of the lifetime of the lowest triplet state, and was found to be of the order of 11 ms. (C) 1999 Elsevier Science B.V. All rights reserved.