Open AccessOrbital angular momentum of an astigmatic Hermite-Gaussian beam
Author(s) -
V. V. Kotlyar,
A. A. Kovalev,
Alexey P. Porfirev
Publication year - 2018
Publication title -
kompʹûternaâ optika
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.491
H-Index - 29
eISSN - 2412-6179
pISSN - 0134-2452
DOI - 10.18287/2412-6179-2018-42-1-13-21
Subject(s) - angular momentum , optics , beam (structure) , gaussian beam , hermite polynomials , gaussian , physics , lens (geology) , m squared , beam diameter , mathematics , classical mechanics , quantum mechanics , laser beams , laser
An explicit formula for the normalized orbital angular momentum (OAM) of an elliptical Hermite-Gaussian (HG) beam of orders (0, n) focused by a cylindrical lens is obtained. In modulus, this OAM can be both greater and smaller than n. If the cylindrical lens focuses not an elliptical, but a conventional HG beam, the latter will also have an OAM that can be both larger and smaller in modulus than that of an elliptical HG beam. For n = 0, this beam converts to an astigmatic Gaussian beam, but, as before, it will still have OAM. With the help of two interferograms, a phase of the astigmatic Gaussian beam is reconstructed, which is then used to calculate the normalized OAM. The values of the OAM calculated by the theoretical formula and using a hybrid method combining modeling with experiment differ only by 6 %.