Femtosecond relaxation of photoexcitations in a solution of a poly(para-phenylene)-type ladder polymer

The primary photoexcitations of a poly(para-phenylene)-type ladder polymer in toluene solution are studied by a time-resolved pump-and-probe technique. Upon exciting the sample with 120 fs pulses a strong stimulated emission is found with a decay time of 190 ps. The stimulated emission centered in the blue/green region at 490 nm shows no spectral overlap with the observed photoinduced absorption, which makes the m-LPPP a promising candidate as the active medium for laser applications.