Generation of laser vortex beams with zero orbital angular momentum and nonzero topological charge
V.P. Aksenov1, V.V. Dudorov1, V.V. Kolosov1,2, G.A. Filimonov1
1V.E. Zuev Institute of Atmospheric Optics of Siberian Branch of the Russian Academy of Science, 1, Academician Zuev square, Tomsk, 634021, Russia
2Tomsk Scientific Center SB RAS, 10/4, av. Academichesky, Tomsk, 634021, Russia
Keywords: вихревой пучок, массив когерентных излучателей, орбитальный угловой момент, топологический заряд, vortex beam, coherent beam array, orbital angular momentum, topological charge
Abstract
The structure of the interference field resulted from the combination of the wave fields of subbeams with apertures located on sides of a regular hexagon is studied. The field on each subapertures is a truncated Gaussian beam with the constant phase shift between neighbor subapertures so as the total phase incursion becomes equal to 2p when walking around the hexagon. It is ascertained that the total angular momentum of the beam synthesized in such a way is zero. There is a region in the central part of the beam where the integral of the density of orbital angular momentum gives the unit orbital angular momentum, and the circulation of the phase gradient at the boundary of this region gives unit topological charge.
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