Influence of polarization on the optical chirality of vortex beams

It is well understood that circularly polarized light possesses optical chirality. This optical chirality can engage with material chirality, leading to optical activity, the underlying physics of chiroptical spectroscopy. Optical vortex beams with azimuthal phase possess helical wavefronts that are chiral. Under spatial confinement (e.g. tight focusing), the polarization state of the input beam and the geometrical wavefront chirality are not independent of one another, and their interplay significantly influences the optical chirality density of the beam. Here we highlight how the state of input beam polarization, e.g. linear, elliptical, and circular, influences the optical chirality of vortex beams. We show that the spatial distributions of the optical chirality density are acutely dependent on the polarization of the input beam, alongside other characteristics like the topological charge and radial index. Most striking is that even an unpolarized optical vortex beam possesses non-zero optical chirality density.