Abstract

In order to generate Bessel beams using Durnin's circular slits, the width of the slits has to be small enough to justify the mathematical principle that the Fourier transform of a thin circular slit placed at the focal plane of a converging lens is a Bessel function of the first kind of zero order. Using circular slits with finite width reduces the depth of field (DOF) and transverse extent of the generated beams. We investigate experimentally and numerically the effect of increasing the slits' width on the quality of the generated nearly Bessel beams. We pay special attention to the longitudinal and transverse extent of the generated beams, their near-diffraction-less property and their quality at the focal plane and along the DOF.

© 2023 The Author(s)