Emission Spectrum of Rhodamine B Dye Lasers

The laser emission spectra of flash-lamp—pumped solutions of rhodamine B in ethanol were examined. A ``hole,'' located at 6261 Å, is seen in the laser emission spectra, but not in the fluorescence spectra. There is no absorption of the unexcited molecules at this wavelength and so the appearance of the hole is tentatively attributed to excited state absorption.