Abstract
The laser dyes, coumarin 2 and coumarin 307, exhibit two amplified spontaneous emission (ASE) bands in certain solvents and in others only one ASE band, The ASE characteristics of these dyes were studied in various solvents to understand the above behaviours. The study shows that a strong long-range interaction between the solvent molecules and the excited dye molecule appears to prevent the formation of the species emitting the longer wavelength ASE, which results in presence of only one ASE band.