Energy transfer excitation in an N 2-laser-pumped coumarin 485-rhodamine B dye mixture through optical gain characteristics

Abstract

The tunability of organic dye lasers has been reviewed by investigating the optical gain characteristics of a coumarin 485-rhodamine B (C 485-Rh B) dye mixture in ethanol subject to N 2 laser excitation. The energy transfer parameters (rate constants of radiative and non-radiative energy transfer processes and the critical transfer radius) have been evaluated with the help of Stern-Volmer plots and the pump power dependence of the gain. The calculated values of radiative and non-radiative energy transfer processes are 0.86 × 10 −11 and 0.45 × 10 −11 L mol −1 s −1 respectively, which shows that the two processes are contributing equally in the present mixture.