Ensemble measurement of the orientation-dependent variations in chromophore lifetimes near a dielectric interface

Abstract

Excited-state lifetimes of fluorophores next to a dielectric interface depend on their orientation relative to the interface. We develop an experimental scheme to assess this effect quantitatively by recording fluorescence decay statistics of dye ensembles using polarized excitation and emission. These experiments allow for the determination of the relative orientation of excitation and emission dipole moments as well as the radiative and nonradiative decay rates of the chromphores. From the latter values, quantum yields can be deduced directly without using reference compounds.