scholarly journals Propagation Properties of an Off-Axis Hollow Gaussian-Schell Model Vortex Beam in Anisotropic Oceanic Turbulence

2021 ◽  
Vol 9 (10) ◽  
pp. 1139
Author(s):  
Xinguang Wang ◽  
Le Wang ◽  
Shengmei Zhao
Keyword(s):  
Dissipation Rate ◽  
Beam Width ◽  
Average Intensity ◽  
Vortex Beam ◽  
Oceanic Turbulence ◽  
Beam Characteristic ◽  
Anisotropic Coefficient ◽  
Higher Temperature ◽  
Inner Scale ◽  
Propagation Properties

Based on the extended Huygens–Fresnel principle and the power spectrum of anisotropic oceanic turbulence, the analytical expressions of the average intensity and coherence properties of an off-axis hollow Gaussian-Schell model (OAHGSM) vortex beam propagating through anisotropic oceanic turbulence were derived. The effects of turbulent ocean and beam characteristic parameters on the evolution properties of the OAHGSM vortex beam were analyzed in detail. Our numerical simulation results showed that the OAHGSM vortex beam with a larger position factor is more focusable. Meanwhile, the OAHGSM vortex beam eventually evolves into a Gaussian-like beam after propagating through the anisotropic oceanic turbulent channel. The speed of this process can be accelerated by the decrease of the hollow order, topological charge, beam width, and transverse coherence width of the beam. The results also indicated that the normalized average intensity spreads more greatly and the spectral degree of coherence decays more rapidly for the smaller dissipation rate of the kinetic energy per unit mass of fluid, the smaller anisotropic coefficient, the smaller inner scale factor, the larger dissipation rate of the mean-squared temperature, and the higher temperature–salinity contribution ratio.

scholarly journals Effects of Oceanic Turbulence on Orbital Angular Momenta of Optical Communications

2020 ◽  
Vol 8 (11) ◽  
pp. 869
Author(s):  
Shuang Zhai ◽  
Yun Zhu ◽  
Yixin Zhang ◽  
Zhengda Hu
Keyword(s):  
Dissipation Rate ◽  
Quantum Coherence ◽  
Single Photon ◽  
Beam Width ◽  
Communication Performance ◽  
Oceanic Turbulence ◽  
Angular Momenta ◽  
Optimal Beam ◽  
Lower Temperature ◽  
Inner Scale

The propagation properties of Laguerre-Gaussian beams in oceanic turbulence are investigated for both single-photon and biphoton cases. For single-photon communication, the channel capacity and trace distance are employed, both of which effectively reveal the communication performance via different viewpoints. For the biphoton case, we consider distributions of quantum resources including entanglement and quantum coherence. Turbulence conditions with a larger inner-scale and anisotropic factors, higher dissipation rate of kinetic energy, lower dissipation rate of the mean-squared temperature, and lower temperature-salinity contribution ratio combined with longer wavelength and an appropriate range of optimal beam width are beneficial to communication performances. Our results provide theoretical significance to improve the orbital-angular-momentum communication via oceanic turbulence.

scholarly journals Propagation Properties of Vortex Cosine-Hyperbolic-Gaussian Beams Through Oceanic Turbulence

2021 ◽  
Author(s):  
Mohamed Lazrek ◽  
Zoubir Hricha ◽  
Abdelmajid Belafhal
Keyword(s):  
Dissipation Rate ◽  
Sea Water ◽  
Turbulent Medium ◽  
Average Intensity ◽  
Underwater Communication ◽  
Salinity Fluctuation ◽  
Oceanic Turbulence ◽  
Diffraction Integral ◽  
Beam Parameters ◽  
Propagation Properties

Abstract Based on the extended Huygens–Fresnel diffraction integral, the analytical expression of the average intensity for a vortex cosine hyperbolic-Gaussian beam (vChGB) propagating in oceanic turbulence is derived in detail. From the derived formula, the propagation properties of a vChGB in oceanic turbulence, including the average intensity distribution and the beam spreading are discussed with numerical examples. It is shown that oceanic turbulence influences strongly the propagation properties of the beam in the turbulent medium. The vChGB may propagate within shorter distance in weak oceanic turbulence by increasing the dissipation rate of mean-square temperature and the ratio of temperature to salinity fluctuation or by increasing the dissipation rate of turbulent kinetic energy per unit mass of sea water. Meanwhile, the evolution properties of the vChGB in the oceanic turbulence are affected by the initial beam parameters, namely the decentered parameter b, the topological charge M, the beam waist width ω0 and the wavelength λ. The obtained results can be beneficial for applications in optical underwater communication and remote sensing domain, imaging, and so on.

scholarly journals Research on Hypergeometric-Gaussian Vortex Beam Propagating under Oceanic Turbulence by Theoretical Derivation and Numerical Simulation

2021 ◽  
Vol 9 (4) ◽  
pp. 442
Author(s):  
Xinguang Wang ◽  
Le Wang ◽  
Shengmei Zhao
Keyword(s):  
Numerical Simulation ◽  
Detection Probability ◽  
Dissipation Rate ◽  
Random Phase ◽  
Simulation Method ◽  
Vortex Beam ◽  
Propagation Characteristics ◽  
Theoretical Derivation ◽  
Oceanic Turbulence ◽  
Phase Screens

In this paper, we use two methods to research the propagation characteristics of a Hypergeometric-Gaussian (HyGG) vortex beam under oceanic turbulence. One is numerical calculation based on the Rytov approximation theory, where the theoretical detection probability equation of the HyGG vortex beam propagating through oceanic turbulence is derived. The other is numerical simulation based on random phase screens model of oceanic turbulence, where the influences generated by oceanic turbulence on the phase and intensity of the propagation beam as well as the propagation of the beam through several independent phase screens, kept at the same distance, have the same effect. The effects of oceanic turbulence parameters and initial beam parameters on the detection probability of the HyGG vortex beam at the receiver are discussed. The results of theoretical derivation are well in agreement with those of numerical simulation, which demonstrated that the numerical simulation method could effectively simulate the complex theoretical derivation. Both results show that with higher dissipation rate of kinetic energy per unit mass of fluid, smaller dissipation rate of mean-squared temperature and lower temperature-salinity contribution ratio comes the better detection probability. Meanwhile, a HyGG vortex beam with smaller topological charge and longer wavelength has a superior turbulent resistance property. It provides a promising way to estimate the propagation characteristics of the optical beams in an underwater environment.

Propagation properties of the rotating elliptical chirped Gaussian vortex beam in the oceanic turbulence

2018 ◽  
Vol 426 ◽  
pp. 456-462 ◽  
Author(s):  
Feng Ye ◽  
Jianbin Zhang ◽  
Jintao Xie ◽  
Dongmei Deng
Keyword(s):  
Vortex Beam ◽  
Oceanic Turbulence ◽  
Propagation Properties

Propagation properties of a partially coherent anomalous hollow vortex beam in underwater oceanic turbulence

2019 ◽  
Vol 437 ◽  
pp. 346-354 ◽  
Author(s):  
Dajun Liu ◽  
Guiqiu Wang ◽  
Honming Yin ◽  
Haiyang Zhong ◽  
Yaochuan Wang
Keyword(s):  
Vortex Beam ◽  
Oceanic Turbulence ◽  
Partially Coherent ◽  
Hollow Vortex ◽  
Propagation Properties

Refractivity turbulence, inner scale, and eddy dissipation rate observations using a balloon-ring platform

2003 ◽  
Author(s):  
Frank D. Eaton ◽  
Patrick R. Kelly ◽  
Demos T. Kyrazis ◽  
Sheldon D. Stokes
Keyword(s):  
Dissipation Rate ◽  
Inner Scale

scholarly journals Nonparaxial Propagation Properties of Specially Correlated Radially Polarized Beams in Free Space

2019 ◽  
Vol 9 (5) ◽  
pp. 997
Author(s):  
Lina Guo ◽  
Li Chen ◽  
Rong Lin ◽  
Minghui Zhang ◽  
Yiming Dong ◽  
...  
Keyword(s):  
Free Space ◽  
Degree Of Polarization ◽  
Average Intensity ◽  
Polarized Beams ◽  
Diffraction Integral ◽  
Spectral Density Matrix ◽  
Potential Applications ◽  
Spectral Degree ◽  
Propagation Properties ◽  
Radially Polarized

A specially correlated radially polarized (SCRP) beam with unusual physical properties on propagation in the paraxial regime was introduced and generated recently. In this paper, we extend the paraxial propagation of an SCRP beam to the nonparaxial regime. The closed-form 3 × 3 cross-spectral density matrix of a nonparaxial SCRP beam propagating in free space is derived with the aid of the generalized Rayleigh–Sommerfeld diffraction integral. The statistical properties, such as average intensity, degree of polarization, and spectral degree of coherence, are studied comparatively for the nonparaxial SCRP beam and the partially coherent radially polarized (PCRP) beam with a conventional Gaussian–Schell-model correlation function. It is found that the nonparaxial properties of an SCRP beam are strikingly different from those of a PCRP beam. These nonparaxial properties are closely related to the correlation functions and the beam waist width. Our results may find potential applications in beam shaping and optical trapping in nonparaxial systems.

scholarly journals Effects of Turbulence on the Vortex Modes Carried by Quasi-Diffracting Free Finite Energy Beam in Ocean

2020 ◽  
Vol 8 (6) ◽  
pp. 458
Author(s):  
Qiyong Liang ◽  
Yixin Zhang ◽  
Dongyu Yang
Keyword(s):  
Gaussian Beam ◽  
Cone Angle ◽  
Wave Structure ◽  
Beam Width ◽  
Finite Energy ◽  
Energy Beam ◽  
Initial Beam ◽  
Oceanic Turbulence ◽  
Wireless Optical Communication ◽  
Ellipticity Parameter

By developing new wave structure function of a beam waves, we derive the transmitting probability of signal vortex modes in oceanic turbulence based on Rytov approximation theory. Applying this transmitting probability of signal vortex modes, we study the influence of oceanic turbulence on the transmittance of the vortex modes carried by Mathieu-Gaussian beam. This model shows the transmitting probability of Mathieu-Gaussian beam with narrow initial beam width, long wavelength, and small ellipticity parameter is higher than the transmitting probability of the signal vortex modes in case of the beam with wide initial beam width, short wavelength, and great ellipticity parameter. Furthermore, when Mathieu-Gaussian beam has a suitable semi-cone angle, the effect of weak-turbulence channel on the transmitting probability of signal vortex modes with different topological charge can be ignored. Mathieu-Gaussian beam is a more suitable carrier for high information channel of underwater wireless optical communication than Laguerre-Gaussian beam.

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