Directly extracting the authentic basis of cylindrical vector beams by a pump-probe technique in an atomic vapor

Abstract

The projective measurement of light polarization is usually employed by using a combination of a quarter-waveplate, half-waveplate, and polarizing beam splitter. This configuration is also widely used for exploring quantum states. However, this kind of measurement destroys the real polarization state of the target. Here, an effective measurement configuration to extract the “authentic basis” of cylindrical vector beams with arbitrary polarization distribution in an atomic vapor is presented. An intense pump beam induces a distribution of atoms at different Zeeman sublevels, which allows for the extraction of the special polarization state of a counter propagated weak probe beam. The extracted part still maintains the original polarization and the vortex phase. Different orders of cylindrical vector beams are tested in this configuration, and the authentic basis of cylindrical vector beams is extracted as predicted. This work has potential applications in atomic physics and polarization optics. Furthermore, it provides a reference for the quantum projective measurement based on atom-optical devices.