Experimental observation of the aberration effects on a radially polarized beam

In the last couple of decades the radially polarized beam has been gaining a lot of importance in diverse areas owing to its unique properties, especially near the focus of a lens. For instance, when focused tightly, the radially polarized beam produces a strong axially polarized field on the optical axis near the focus. Some of the areas where the radially polarized beam is found to be useful are optical trapping, laser machining, optical data storage, optical superresolution, and so on. Considering the fact that there is not any optical system that can be treated as perfectly aberration free, the applications of the radially polarized beam can, in practice, more or less be affected by the presence of aberrations. Indeed, there have been studies to understand the properties of the radially polarized beam in the presence of various aberrations. However, most such studies have been purely theoretical without being complimented by experimental results. In this paper, we present a comprehensive experimental investigation on the effect of aberrations on a focused radially polarized beam. The accuracy of our experimental results is confirmed by comparing them with the equivalent numerical simulation results.