Comment on the paper “Conversion of Laguerre-Gaussian beams into Gaussian beams of reduced focal spot by use of a circular echelon”

Abstract It is shown that the work entitled “Conversion of Laguerre-Gaussian beams into Gaussian beams of reduced focal spot by use of a circular echelon” repoted by S.Cherif et al. (Optik 127 (2016) 3134–3137), follows the same procedures as presented in the papers of the authors ([A. Hasnaoui, A.Bencheikh and K.ait ameur, Opt. Lasers Eng. 49 (2011) 248–251], [A. Hasnaoui, A. Bencheikh, M. Fromager, E. Cagniot, K. Ait-Ameur, Creation of a sharper focus by using a rectified TEMp0beam, Opt. Commun. 284 (2011) 1331–1334]), but concludes that their results are substantially different from the results of the authors. We find that there is no new result in the whole work, in addition there are big mistakes that we look to clarify and to correct.