Channel capacity and quantum entanglement of autofocusing hypergeometric-Gaussian beams through non-Kolmogorov turbulence

Abstract

We establish propagation models for distributing autofocusing hypergeometric-Gaussian (HyGG) beams via non-Kolmogorov atmospheric turbulence in the single-photon and biphoton cases. Analytical expressions of the channel capacity and entanglement are employed to explore the communication performance in turbulence. It can be demonstrated that in the single-photon case, a lower hollowness parameter and larger topological charge could contribute to the anti-interference ability of HyGG beams. Such an anti-interference ability could be affected by the autofocusing distance more severely for beams with larger topological charges. In addition, the channel capacity of beams at a certain distance decays rapidly at first before it grows steadily with the increase in the power-law exponent of the non-Kolmogorov spectrum. For the biphoton case, the higher hollowness parameter, larger power-law exponent of the non-Kolmogorov spectrum and larger topological charge make HyGG beams maintain a high concurrence at longer distances. We believe that our results could serve as a reference for improving the quality of orbital-angular-momentum communication of HyGG beams via atmospheric turbulence.

Properties of focused Laguerre–Gaussian beam propagating in anisotropic ocean turbulence

“…The carrier wave carrying OAM is often referred to as vortex beams that have a wide range of applications in optical tweezers, particle manipulation, and quantum entanglement. [4][5][6][7] In particular, the efficiency and performance of vortex beam-based communication systems can be greatly improved in that the number of signal bits each photon carries is log 2 N, [8] where N is the number of OAM modes that can be available for information mulplexing, which is one of the research hotspots in the field of free-space optical communication. [9][10][11] It is worth noting that there appears to be distortion of the signal OAM mode and crosstalk between different energy states of adjacent OAM modes during the transmission of the vortex beam in turbulent medium, reducing the channel capacity of the OAM information transmission system severely, where the effect of refractive index fluctuation of turbulent medium is crucial.…”

Performance analysis of an underwater wireless optical communication link with Lommel beam

“…In recent years, the application of multiplexing techniques such as orthogonal frequency division multiplexing and optical code division multiple access, etc has contributed to the rapid development of high-capacity free space optical communications [2][3][4]. On the other hand, the orbital angular momentum (OAM) [5][6][7][8] multiplexing utilizes vortex beam as information carrier, providing a new coding scheme with high information capacity and high spectral efficiency for UWOC links by taking advantage of the orthogonality between different OAM modes and the infinity of the values of the OAM quantum number, which has also aroused a great deal of interest from researchers [9][10][11][12][13][14][15][16]. However, the presence of turbulence affects the wavefront structure of the optical vortex, causing the distortion of the signal OAM mode and the crosstalk between adjacent OAM modes, which degrades the performance of UWOC links greatly [17][18][19][20].…”

The spiral phase spectrum of the composite power Gaussian vortex beam in plasma sheath turbulence

“…In 1992, Allen et al demonstrated that each photon of the Laguerre-Gaussian(LG) vortex beam carries orbital angular momentum(OAM), which can provide an additional degree of freedom for information multiplexing due to its orthogonality and completeness. This sparked widespread interest of researchers in the vortex beams carrying OAM together with their transmission properties through turbulent media [6][7][8][9][10][11][12]. The correlated investigations indicate that utilizing vortex beam as source beam can effectively mitigate wavefront distortion and reduce turbulent interference.…”