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Topological charge of optical vortices devoid of radial symmetry
V.V. Kotlyar 1,2, A.A. Kovalev 1,2

IPSI RAS – Branch of the FSRC "Crystallography and Photonics" RAS,
443001, Samara, Russia, Molodogvardeyskaya 151,
Samara National Research University, 443086, Samara, Russia, Moskovskoye Shosse 34

 PDF, 1336 kB

DOI: 10.18287/2412-6179-CO-719

Pages: 510-518.

Full text of article: Russian language.

Here we theoretically obtain values of the topological charge (TC) for vortex laser beams devoid of radial symmetry: asymmetric Laguerre-Gaussian (LG) beams, Bessel-Gaussian (BG) beams, Kummer beams, and vortex Hermite-Gaussian (HG) beams. All these beams consist of conventional modes, namely, LG, BG, or HG modes, respectively. However, all these modes have the same TC equal to that of a single constituent mode n. Orbital angular momenta (OAM) of all these beams, normalized to the beam power, are different and changing differently with varying beam asymmetry. However, for arbitrary beam asymmetry, TC remains unchanged and equals n. Superposition of just two HG modes with the adjacent numbers (n, n+1) and with the phase retardation of (pi)/2 yields a modal beam with the TC equal to – (2n+1). Numerical simulation confirms the theoretical predictions.

topological charge, optical vortex, asymmetric beam.

Kotlyar VV, Kovalev AA. Topological charge of optical vortices devoid of radial symmetry. Computer Optics 2020; 44(4): 510-518. DOI: 10.18287/2412-6179-CO-719.

This work was partly funded by the Russian Foundation for Basic Research under project No. 18-29-20003 (section “Derivation of the topological charge of asymmetric optical vortices”), the Russian Science Foundation under project No. 18-19-00595 (section “Derivation of the topological charge of Hermite-Gaussian vortex beams”, and the RF Ministry of Science and Higher Education within a government project of FSRC “Crystallography and Photonics” RAS (section “Numerical simulation results”).


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