Focus shaping of cylindrically polarized Bessel-Gaussian beam modulated by Bessel gratings by a high numerical aperture objective

The focus-shaping technique of the cylindrically polarized Bessel-Gaussian-like beam, referred to the cylindrically polarized Bessel-Gaussian beam modulated by Bessel gratings, propagating through a high numerical-aperture lens is investigated theoretically and numerically in this paper, using the vector diffraction theory method. Results show that the intensity distribution in the focal region can be influenced considerably by: the beam topological charges (m, n), the beam parameter beta and the polarization angle phi(0). The intensity distribution in focal region can be tailored considerably by appropriately adjusting the polarization angle. Peak-centered, donut and flattop focal shapes with extended focal depth which are potentially useful in optical tweezers, material processing and laser printing can be obtained using this technique.