Analysis of polarisation states at sharp focusing

We investigate the inter-relation of the phase and polarisation singularities in systems with high numerical aperture. We consider sharp focusing by means of three types of systems: a micro-objective, a diffractive axicon and a micro-objective combined with an axicon-type multichannel diffractive optical element. The complex transmission function of the element is matched to optical vortices. We analyse numerical results of Gaussian laser beam focusing with various polarisations and phase distributions in detail.