Phys.org  May 7, 2018
An optical vortex is a light wave with a twisting wavefront around its propagation axis and null intensity in the beam center. Accessible intensity of optical vortices have been limited to material ionization threshold which might be removed by using the plasma medium. Researchers at Princeton University propose the design of suitably magnetized plasmas which, functioning as a q-plate, leads to a direct conversion from a high-intensity Gaussian beam into a twisted beam. A circularly polarized laser beam in the plasma accumulates an azimuthal-angle-dependent phase shift and hence forms a twisting wavefront. Extremely high-resolution images are vital to study new materials, and microbes… read more. TECHNICAL ARTICLE
Converting a Gaussian laser beam into an optical vortex in magnetized plasma. Credit: Kenan Qu, Princeton University