Time-resolved stimulated emission in an alpha-sexithienyl thin film

We have investigated the stimulated emission of an evaporated thin Blm of a lpha -sexithienyl at 20 g. We have performed femtosecond differential trans mission measurements with excitation energies around 2.35 eV and probing th e spectral region from 2 to 2.65 eV. The results are compared to time-resol ved photoluminescence spectra. We observe amplification of the probe light at the spectral position of a sharp peak measured in time-resolved photolum inescence. The stimulated emission decays with a time constant of 2.5 ps, ( C) 2001 Elsevier Science B.V. All rights reserved,