Experimental demonstration of generation of longitudinal component of the electric field on the optical axis by high-aperture binary axicon for linear and circular polarization of the incident beam

We consider the diffraction of the laser radiation with different polarization on high-aperture binary axicon with different structures. We have performed theoretical analysis of axicon diffraction with expansion in plane waves and shown that depending on the polarization either the longitudinal or the transverse components of the electric field are focused on the optical axis. Analytically and numerically shown that the asymmetry in the structure of the axicon can provide the longitudinal component on the optical axis for the linear and circular polarization of the incident beam. High-aperture binary axicons of three configurations – axisymmetric, bi-axicon and spiral - are produced by electron beam lithography technology. We have performed experimental measurements in the near-field diffraction for the most common and easily implemented types of polarization of the incident beam - linear and circular. The experimental results show agreement with the theoretical studies.