Nonparaxial Propagation of a Radially Polarized Beam Diffracted by an Annular Aperture

Based on the vectorial Rayleigh diffraction integral, the integral formulae of three electromagnetic field components for radially polarized Laguerre–Gaussian beams after diffraction by an annular aperture and the propagation distance in nonparaxial regimes are presented. The diffraction by a circular aperture or a circular disk or propagation in free space can be treated as the special cases of this general result. The numerical simulation shows that the electric field intensity distributions closely depend on both the inner truncation parameters and the outer truncation parameters of the annular aperture, as well as on the ratio of the waist of the incident Laguerre–Gaussian beam to the wavelength.