Formation of three-dimensional intensity distributions by diffraction of laser radiation on annular apertures at sharp focusing

We consider formation of three-dimensional intensity distributions by means of diffraction of laser radiation on ring apertures in conditions of sharp focusing. Various combinations of vortex phase dependence in the ring apertures for the most common types of polarization of an incident beam are investigated. It is shown, that when two narrow ring apertures are used a three-dimensional periodic structure is formed in focal area. It is an interference of beams of Bessel type. The form of these structures can be controlled due to polarization and phase variations.