Generation and control of tornado waves by means of ring swallowtail vortex beams

Generation of a modulated versatile spiral beam with varying intensity distribution along the propagation

A new type of versatile spiral beam (VSB) is generated based on the competition mechanism between the self-focusing property of ring Airy beam and metalens phase distribution, which exhibits twisted properties and optical bottle structure along the propagation direction. The number of spiral lobes, rotation direction, shape and magnification times on the cross section of the proposed beam can be customized by flexibly tuning diffraction distance, topological charge and constant parameter. Therefore, the VSB can be viewed as tunable three-dimensional (3D) spiral beam, and our scheme has the superiority with more diverse and tunable intensity distribution. The properties of intensity distribution variation depended on the propagation distance and topological charge are demonstrated convincingly by employing the Poynting vector intuitive presentation the energy flow. The VSBs with the aid of above-mentioned properties are beneficial for guiding microparticles along the designed spiral path and capturing multiple microparticles into the closed dark regions. Finally, the modulated spiral beams are implemented as tool for particle manipulation in the three dimensional space to demonstrate the advantages of the modulated spiral beam and we can observe the stable trapping of the particles.

Optical vortices shape optical tornados

We demonstrate that by seeding an accelerating ring-Airy beam with a finite number of off-axis optical vortices, it transforms into a tornado wave (ToW) upon propagation. Using numerical simulations, we show that both the spiraling high-intensity lobes and the optical vortices exhibit angular acceleration and follow interwinding braid-like trajectories. Likewise, we study the effect of the number, position, and topological charge of the vortices on the propagation dynamics and reveal the connection between optical vortices and optical tornados.

Switchable optical ring lattice in free space

Optical lattices with spatially regular structures have recently attracted considerable attention across physics and optics communities. In particular, due to the increasing emergence of new structured light fields, diverse lattices with rich topology are being generated via multi-beam interference. Here, we report a specific ring lattice with radial lobe structures generated via superposition of two ring Airy vortex beams (RAVBs). We show that the lattice morphology evolves upon propagation in free space, switching from a bright-ring lattice to dark-ring lattice and even to fascinating multilayer texture. This underlying physical mechanism is related to the variation of the unique intermodal phase between the RAVBs as well as topological energy flow with symmetry breaking. Our finds provide an approach for engineering customized ring lattices to inspire a wide variety of new applications.

Generation and control of the circle Olver beams

The circle Olver beams (COBs) generated by modulation on the basis of a new type of Olver beam are presented numerically and experimentally. The zeroth order COB is the circle Airy beam. We demonstrate auto-focusing of the COBs with both inward and outward accelerations, where the odd order COBs display auto-defocusing while the even order COBs (ECOBs) tend to focus more abruptly. We also explore the effect of the decay factor and the scaling factor on the beams' focusing properties, such as the initial energy distribution, the focusing position, the focusing intensity and the focusing depth, by using the parity mode. In addition, we verify the self-healing property of the COBs. Finally, we set up an experimental platform to implement particle capture and manipulation with the ECOBs. Our results offer practical applications for particle manipulation, laser processing, etc.