Large-scale sharply bending paraxial beams

Abstract

We demonstrate optical sharply bending beams under the paraxial condition. The curved path followed by these beams arises from the intersection of geometrical rays nearly parallel to the optical axis rather than the envelope of a bundle of tangential rays, whereby conventional bending beams were routinely designed. Compared with Airy beams, such sharply bending beams can turn at a much larger angle, and, surprisingly, exhibit an expedited self-healing process especially when they encounter an obstacle farther away. Furthermore, a simple method to preset the beam path is put forward, leading to free-space active routing of laser peak intensity even to 90° along circular and elliptical trajectories of macroscale. Our approach can be exploited to design sharply curved wave-packets in other physical systems.

Generation of shaping nondiffracting structured caustic beams on the basis of stationary phase principle

“…Figure 1 shows that the concepts of geometrical and wave optics work excellently when they are used to describe the phenomenon of caustics. Our scheme can be potentially extended to design other caustics-related beams [37] .…”

Needle beams: a review

“…By an appropriate programming of adapted phase maps, accelerated paraxial needle beams can be shaped that 'propagate' along curved trajectories (compare [131][132][133]140,141]) (some remarks on the controversial discussion about the propagation of accelerated beams can be found in ref [83]). Tunable curvilinear beams are interesting for particle manipulation, switching between channels of photonic chips, materials processing, directing electrical discharges, particle analysis by scattering, optofluidics, and other applications [141].…”