Generation of Tunable Focal Spot and Focal hole by Radially Polarized Axisymmetric Bessel-modulated Gaussian beam

Abstract

In recent years, an Axisymmetric Bessel-modulated Gaussian beam with quadratic radial dependence (QBG beam) has attracted very much. In this paper, Focal shift in radially polarized QBG beam with radial variance phase wavefront is investigated theoretically byvector diffraction theory. The wavefront phase distribution is cosine function of radial coordinate. Simulation results show that the intensity distribution in focal region of the radially polarized QBG beam can be adjusted considerably by small beam parameter