Terahertz rate rotating helical intensity beams

As laser applications continue to advance, other spatial intensity distributions that are not Gaussian are increasingly being used. For instance, Bessel beams, which have a small diameter and a very long focal zone allow the fabrication of high aspect ratio modifications in transparent materials. Higher-order Laguerre–Gauss modes are used in particle manipulation and even for multiplexing in optical communication. However, pulse shaping, apart from pulse compression, has been overlooked but can lead to laser micromachining, particle manipulation, and improvements in optical communication quality and efficiency. In this paper, we demonstrate a method of constructing a helical intensity distribution beam that is modified in space and time. In space, it comprises a different number of intensity maxima, while in the time domain, it exhibits rotation around the propagating axis. We show the numerical simulations of the resultant beam and a way of realizing such a beam experimentally. Results show a tunable rotation speed helical beam with angular speeds up to at least 4.5 mrad/fs. With the increase of the pulse energy, these beams show potential for material ablation applications. •Novel dynamic helical intensity pulsed beam with tunable rotation speeds up to 4.5 mrad/fs.•Helical pulsed beams are generated by two coherent chirped pulses with different vorticity numbers.•High-efficiency beam generation using birefringent elements.•Demonstrated potential for laser material ablation with helical rotating beams.•Scalability to higher energy pulses.