Effects of the solvent environments on the ASE from coumarin 503

In this work, the spectral and the amplified spontaneous emission (ASE) characteristics of coumarin 503 have been investigated in different solvents and concentrations. The absorption and fluorescence spectra of coumarin 503 showed only one band; this indicates no dimer or excimer formation, respectively. Under certain concentrations, solvents and pump power energies, coumarin 503 exhibits dual ASE peaks; (475 nm and 495 nm) even though for the same solutions there was only one absorption or fluorescence band. The shorter wavelength (475 nm) coincides to fluorescence band while the longer wavelength (LW) at 495 is an abnormal peak. This abnormal peak (495 nm) could be attributed to the combination of two molecules in an excited state and the solvent acting as a bridge between them under high power excitation.