Ultrafast light-emission processes in poly(para-phenylene)-type ladder polymer films

We report on a comprehensive characterization of the ultrafast emission pro cesses in films of methyl-substituted poly(para-phenylene)-type ladder poly mer, by femtosecond frequency up-conversion and pump-probe spectroscopy. We found that bimolecular recombination mechanisms mainly govern the ultrafas t emission processes, at high excitation fluences, in films with thickness well below cutoff for waveguiding of the emitted Light. Amplified spontaneo us emission strongly affects emission processes (spectral narrowing, lumine scence and gain temporal dynamics) in films with superior optical confineme nt properties. [S0163-1829(99)01817-2].