Experimental generation of cylindrical vector modes via an astigmatic mode converter

In this work, we propose and demonstrate experimentally a compact technique for the generation of cylindrical vector beams, based on a Michelson interferometer and a $\pi$-astigmatic mode converter, capable of inverting the topological charge of higher-order Laguerre-Gauss beams. Compared to previously demonstrated methods, this is relatively easy to align, and very compact. In addition, it generalises the concept of astigmatic mode conversion, commonly associated with scalar beams, to vector beams with non-homogeneous polarisation distribution. We anticipate that many of the applications based on Michelson interferometers will benefit from the unique properties of vector beams.