Spiral spectrum of anomalous vortex beams propagating in a weakly turbulent atmosphere |
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| Authors: | Fang Li Hui Lui Jun Ou |
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| Affiliation: | 1. School of Science, Beijing University of Civil Engineering and Architecture, Beijing, People’s Republic of Chinalifang@bucea.edu.cn;3. School of Electrical and Information Engineering, Beijing University of Civil Engineering and Architecture, Beijing, People’s Republic of China;4. School of Communication Engineering, Hangzhou Dianzi University, Hangzhou, People’s Republic of China |
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| Abstract: | ABSTRACTWe study the spiral spectrum of anomalous vortex beams propagating through a turbulent atmosphere. Based on the Huygens–Fresnel integral and the Rytov approximation, the integral expression and then the analytical expression for the spiral spectrum of anomalous vortex beams in the weakly turbulent atmosphere are derived. The capacity of wireless optical links using the anomalous vortex beam is obtained. It is found that the spiral spectrum of the anomalous vortex beam is less affected by turbulence than that of the Laguerre-Gaussian beam. And thus, the information capacity of wireless optical links using the anomalous vortex beam is larger than that using the Laguerre-Gaussian beam. The influence of beam order, wavelength, topological charge, propagation distance, refractive index structure constant and the radius of receiver aperture on spiral spectrum is investigated. These results contribute to reduce the disturbing effects of atmospheric turbulence on the orbital angular momentum of the vortex beam. |
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| Keywords: | Anomalous vortex beam spiral spectrum atmospheric turbulence Laguerre–Gaussian beam capacity |
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