Backward flow of energy for an optical vortex with arbitrary integer topological charge
Kotlyar V.V., Kovalev A.A., Nalimov A.G.

 

Image Processing Systems Institute оf RAS – Branch of the FSRC “Crystallography and Photonics” RAS, Samara, Russia,
Samara National Research University, Samara, Russia

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Abstract:
We analyze the sharp focusing of an arbitrary optical vortex with the integer topological charge m and circular polarization in an aplanatic optical system. Explicit formulas to describe all projections of the electric and magnetic fields near the focal spot are derived. Expressions for the near-focus intensity (energy density) and energy flow (projections of the Pointing vector) are also derived. The expressions derived suggest that for a left-hand circularly polarized optical vortex with m > 2, the on-axis backward flow is equal to zero, growing in the absolute value as a power 2(m – 2) of the radial coordinate. These relations also show that upon the negative propagation, the energy flow rotates around the optical axis.

Keywords:
backward energy flow, optical vortex, rotating beams, Umov-Poynting vector.

Citation:
Kotlyar VV, Kovalev AA, Nalimov AG. Backward flow of energy for an optical vortex with arbitrary integer topological charge. Computer Optics 2018; 42 (3): 408-413. DOI: 10.18287/2412-6179-2018-42-3-408-413.

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