Laser gain and excited-state absorption measurements in phenylene-vinyleneoligomer (1,4-bis-(alpha-cyanostyryl)-2,5-dimethoxybenzene)

The pump-probe technique, was used to measure the effective stimulated emis sion and excited-state absorption cross-sections of phenylene-vinylene olig omer (1,4-bis-(alpha-cyanostyryl)-2,5-dimethoxybenzene) dissolved in toluen e for different probe wavelengths. The effective stimulated emission cross- section corresponding to the S-1 --> S-0 transition was found to be positiv e. The possible laser tuning ranges have been determined. Time-resolved exc ited-state absorption permitted simultaneous measurements of the excited-st ate absorption cross section and the: lifetime of the lowest triplet state T-1 and was found to be of the order of 11 ms. (C) 2000 Elsevier Science B. V. All rights reserved.