Abstract
The shape of focal spot is affected by the distribution of polarization and phase on the cross-section of the incident beam. We demonstrated the spatial resolution enhancement effect using the difference of the focal spots between a linearly polarized beam and an azimuthally polarized beam. The azimuthally polarized beam has the vortex of polarization on the cross-section of the beam. Since the vortex of the azimuthally polarized beam forms a doughnut shaped focal spot, the spatial resolution is expected to increase with the difference image between linearly polarized beam excitation/detection and azimuthally polarized beam excitation/detection. We applied an eight segmented polarization mode converter, which was developed by ourselves and could switch those polarization modes of the excitation beam electrically, to a commercial confocal microscope. We derived the suitable weight of subtraction theoretically, and demonstrated the spatial resolution enhancement effect by observing the stained cell cytoskeleton.
