Optical vortex scanning inside the Gaussian beam

Abstract

We discussed a new scanning method for optical vortex-based scanning microscopy. Theoptical vortex is introduced into the incident Gaussian beam by a vortex lens. Then thebeam with the optical vortex is focused by an objective and illuminates the sample. Bychanging the position of the vortex lens we can shift the optical vortex position at thesample plane. By adjusting system parameters we can get 30 times smaller shiftat the sample plane compared to the vortex lens shift. Moreover, if the rangeof vortex shifts is smaller than 3% of the beam radius in the sample plane theamplitude and phase distribution around the phase dislocation remains practicallyunchanged. Thus we can scan the sample topography precisely with an optical vortex.