Elimination of fluorescence intensity difference in orientation determination of single molecules by highly focused generalized cylindrical vector beams

The orientation of the dipole moment, which is one of the important parameters in single-molecule fluorescence spectroscopy and often influenced by subtle changes in the local environment, is determined by highly focused generalized cylindrical vector beams combined with a confocal far-field microscope. As compared to the case of a radially polarized incident beam, the numerical results demonstrate that fluorescence intensity difference among single molecules with different orientations can be effectively overcome for a particular polarization direction of the generalized cylindrical vector beam, which may increases the signal-to-noise ratio of the practical experiments and then ease the difficulty in orientation determination of single molecules.