Excitation-Polarization Effects on Single-Molecule Fluorescence on Quartz Surfaces

The single-molecule fluorescence of dye molecules on quartz surfaces was studied by using a photon-counting video microscopy. We observed fluorescent spots including a countable number of molecules. The orientation of the transition dipole of the molecules on quartz surfaces was found to vary widely in contrast to that observed on Si surfaces where the transition dipole was highly ordered.