FOCUS SHAPING OF CYLINDRICALLY POLARIZED VORTEX BEAMS BY A LINEAR AXICON

Abstract

Focus shaping of cylindrically polarized vortex beams (CPVBs) by linear axicon is studied theoretically. Vector diffraction theory has been used to derive the expressions of the light field in the focal region. It is shown that a different intensity distribution in the focal region can be obtained by adjusting the topological charge, the polarization rotation angle and the numerical aperture maximal angle. A focal spot, a dark channel and a flat-topped shapes are formed by choosing proper values of parameters. A controllable polarization state of dark channel is obtained. The different focal region shapes may find wide applications such as material processing and optical tweezers.