Correlations between photophysics and lasing properties of dipyrromethene–BF2 dyes in solution

UV–Vis absorption, fluorescence (steady-state and time-correlated) and lasing properties of three pyrromethene–BF2 dyes (PM546, PM556 and PM567) have been determined in several solvents. Good correlations between photophysical properties and lasing characteristics of these dyes have been obtained not only for a given dye in several solvents but also for the three dyes in a common solvent. Both the observed spectral changes and the deactivation mechanism affecting the lasing gain are explained on the basis of the possible resonance structures of the chromophore.