Sharp Focus Area of Radially-Polarized Gaussian Beam Propagation Through an Axicon

Based upon developed radial FDTD-method, used for solution of Maxwell equations in cylindrical coordinates and implemented in Matlab-7.0 environment, we simulated focusing of the annular Gaussian beam with radial polarization by conical microaxicon with numerical aperture 0.60. It is shown that the area of focal spot (defined as area where intensity exceeds half of its maximum) can be 0.096λ, and focal spot diameter equals to 0.35λ.