Regular Article

The formation of a beam propagating in a slow-expansion mode on diffraction of a circular segment-shaped laser beam

Physics and Technology department, Yanka Kupala State University of Grodno, 22 Ozheshko street, Grodno 230023, Belarus

^a e-mail: zeylikov@gmail.com

Received: 1 December 2018
Revised: 6 May 2019
Published online: 21 August 2019

Abstract

The light field structure on diffraction of a circular segment-shaped laser beam was studied. At distances of 6–20 cm from a segment-shaped aperture obstructing a circular laser beam, the formation of the beam structure propagating in a slow-expansion mode was detected. The diffracted beam structure has been fully formed in the shadow region at a distance of 20 cm from the obstacle. In the boundary region of the aperture straight edge, the helical beams of the opposite topological charges were reconstructed by the theoretical 3-D propagation of the laser beam.