Autofocusing characteristics of Bessel-modulated circular Airy and circular Airyprime beams propagating in free space

The propagation dynamics and autofocusing behaviors of the Bessel-modulated circular Airy beam (BMCAB) and the Bessel-modulated circular Airyprime beam (BMCAPB) in free space are investigated. The results demonstrate that the number (one or two) of focal points of these two beams could be manipulated by the initial beam width w 0 , the primary ring radius r 0 , and the exponential decay factor a . The BMCAPB possesses stronger focusing ability and wider dual-focus adjustable range than the BMCAB, whereas the BMCAB can be flexibly switched between single-focus and dual-focus modes. The focusing positions and the peak intensity can be precisely controlled by the focal length f . Interestingly, a needle-like optical field with controllable needle length could be formed by changing the focal length f of the BMCAB. Furthermore, the BMCAPB provides stronger optical trapping at the front focus, while the BMCAB offers more stable forces at the rear focus.