Generalized and multiplexed $q$-plates: experimental implementation
In this paper we generalize the concept of $q$-plate, allowing arbitrary functions of both the radial and the azimuthal variables, and study their effect on uniformly polarized beams in the near and far-field regime. This gives a tool for achieving beams with hybrid states of polarization (SoPs), and alternative phase and intensity distributions. We also implement an experimental device based on a liquid crystal on silicon (LCoS) display for emulating these generalized $q$-plates. Moreover, we propose an application that takes advantage of the pixelated nature of this kind of devices for creating arbitrary superpositions of vector and vortex beams by representing onto the LCoS randomized combinations of two different $q$-plates, i.e. multiplexed $q$-plates. Great agreement is found between theoretical and experimental results.