Emission spectrum of concentrated dye solutions excited by high-power laser radiation

Abstract

Emission spectra of concentrated (~1018–1019 cm–3) ethanol solutions of Rhodamine C excited by high-power (~1025–1026 cm–2s–1) laser radiation were measured. The emission spectrum consists of two narrow bands (with half-widths of ~200–300 cm–1). The long-wavelength band was interpreted as cooperative spontaneous emission, and the short-wavelength band was assigned to the amplified spontaneous emission. The ratio of their intensities depends on the dye concentration and the pump power density. The ratio of band intensities is assumed to be determined by the dephasing rate of excited molecules responsible for cooperative spontaneous emission.