Fractal Conical Lens Optical Tweezers

We propose a novel optical tweezers composed of an annular beam with alternate radially and azimuthally polarized rings modulated by a fractal conical lens (FCL) and demonstrate its optical forces on Rayleigh dielectric particles both analytically and numerically. Owing to the optical system's particular focusing properties, which could generate a dark-centered or peak-centered intensity distribution in the focal region when selecting an appropriate truncation parameter in front of the focusing lens, the proposed FCL optical tweezers could selectively trap and manipulate dielectric mesoscopic particles with low- or high-refractive indices by appropriately adjusting the radius of the pupil or the beam. Finally, the stability conditions for effective trapping and manipulation Rayleigh particles are analyzed.