Vector Analysis of Laser Beam Propagation

Based on the Huygens–Fresnel principle, we present a vector description of laser beam propagation without the limitations of the paraxial approximation. A numerical model is developed for a family of radially (azimuthally) polarized beams with circular symmetry of all parameters, including polarization. The model takes into account the transverse nature of the electromagnetic wave as it propagates from points of a given cross section to observation points. Diffraction from a narrow annular slit and the evolution of beams with damaged amplitude–phase field distributions are considered. On the basis of numerical calculations, a method for extracting high-quality radiation from lasers with a coaxial active medium geometry is proposed.