Generation of vortex N 2 <i/> + lasing

Abstract

Harnessing structured light is fascinating for its multidisciplinary applications, e.g., in remote driving microrobots, sensing, communications, and ultrahigh resolution imaging. Here, we experimentally demonstrated the generation of a vortex N2+ lasing pumped by a wavefront structured near-IR femtosecond pulse with orbital angular momentum. The topological charge of the N2+ lasing was measured to be twofold that of the pump beam. Compared to the case with a pump beam of a plane wavefront, the N2+ lasing generation efficiency is much higher for the vortex pump beam at high pumping energy, which has a higher clamping intensity by reducing the on-axis plasma density. Our results herald a march toward remote structured N2+ lasing.