Taming electric discharges using optical beams

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Electric discharges are ubiquitous in modern technologies and find applications in numerous areas ranging from micromachining to pollution control [1, 2]. Yet, despite the long history of this topic, developing methods to effectively control and shape the path of an electrical spark still remains a significant challenge. Lasers have been frequently used to encourage a discharge through photoinduced plasma channels—but even so, controlling the discharge path has had limited success so far. Clerici et al. [3] have demonstrated that properly shaped laser beams can provide an effective method to control the electric discharge path by virtue of the ionization they induce in air, introducing therefore a novel tool for improving and enabling new approaches in the applications of electric sparks, such as cutting, welding and machining. Up to now, most of the experiments on this topic relied on standard Gaussian optical beams. The recent introduction of self-bending Airy beams in optics [4] has opened up new opportunities in terms of propagating beams along complex trajectories—a feature that Clerici et al. [3] used to control electric discharges. By manipulating the specific shape of a laser beam, it is indeed possible to precisely control the trail of a spark. Their results indicated that the self-healing properties associated with Airy and Bessel laser wavefronts can be readily transferred to the electrical discharge, which also self-heals and resumes its original trajectory even after a direct hit on an obstacle. In this regard, not only is the unpredictability that usually accompanies this phenomenon removed, but also the discharge can be manipulated in such a way that the resulting arc can bypass an object placed in the line of sight between the electrodes. Clerici et al. [3] have also investigated the impact of beam shaping on the guided electric discharge considering