scholarly journals Propagation Properties of an Astigmatic Cos-Gaussian Beam through Turbulent Atmosphere

2021 ◽  
Vol 299 ◽  
pp. 02003
Author(s):  
Kaicheng Zhu ◽  
Xiaolei Ma ◽  
Chang Gao ◽  
Dengjuan Ren ◽  
Jie Zhu
Keyword(s):  
Gaussian Beam ◽  
Atmospheric Turbulence ◽  
Intensity Distribution ◽  
Turbulent Atmosphere ◽  
Structure Constant ◽  
Propagation Distance ◽  
Turbulent Structure ◽  
Fresnel Integral ◽  
Propagation Properties ◽  
Distribution Behaviour

We use the extended Huygens-Fresnel integral to investigate the propagation properties of a cos-Gaussian beam (cosGB) with astigmatism in atmospheric turbulence. The intensity distribution behaviour along the propagation distance for an astigmatic cosGB in atmospheric turbulence are analytically and numerically demonstrated. Some novel phenomena are presented graphically, indicating that the intensity distribution and the on-axial intensity closely depend on the astigmatic parameter and the turbulent structure constant of the cosGBs in the atmospheric turbulence.

scholarly journals Behavior of the Central Intensity of Generalized Humbert-Gaussian Beams Against the Atmospheric Turbulence

2021 ◽  
Author(s):  
Naima Nossir ◽  
Latifa Dalil-Essakali ◽  
Abdelmajid Belafhal
Keyword(s):  
Atmospheric Turbulence ◽  
Intensity Distribution ◽  
Turbulent Atmosphere ◽  
Incident Beam ◽  
Paraxial Approximation ◽  
Gaussian Beams ◽  
Central Intensity ◽  
Fresnel Integral ◽  
Special Cases ◽  
Beam Parameters

Abstract Based on the generalized Huygens-Fresnel integral in the paraxial approximation and on the Rytov theory, the analytical expression of the axial intensity distribution for the Generalized Humbert-Gaussian beams (GHGBs) propagating through a turbulent atmosphere is derived in this work. The results for the special cases of GHGBs are deduced from our study and illustrated numerically. The influence of the turbulent strength and the incident beam parameters on the propagation of these beams in the atmospheric turbulence is investigated and discussed in detail.

scholarly journals Nonparaxial Propagation of Vectorial Elliptical Gaussian Beams

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Wang Xun ◽  
Huang Kelin ◽  
Liu Zhirong ◽  
Zhao Kangyi
Keyword(s):  
Gaussian Beam ◽  
Propagation Distance ◽  
Diffraction Integral ◽  
Peak Intensity ◽  
Propagation Properties ◽  
Relationship Of ◽  
The Relationship ◽  
Analytical Expressions ◽  
Nonparaxial Propagation ◽  
Special Case

Based on the vectorial Rayleigh-Sommerfeld diffraction integral formulae, analytical expressions for a vectorial elliptical Gaussian beam’s nonparaxial propagating in free space are derived and used to investigate target beam’s propagation properties. As a special case of nonparaxial propagation, the target beam’s paraxial propagation has also been examined. The relationship of vectorial elliptical Gaussian beam’s intensity distribution and nonparaxial effect with elliptic coefficientαand waist width related parameterfωhas been analyzed. Results show that no matter what value of elliptic coefficientαis, when parameterfωis large, nonparaxial conclusions of elliptical Gaussian beam should be adopted; while parameterfωis small, the paraxial approximation of elliptical Gaussian beam is effective. In addition, the peak intensity value of elliptical Gaussian beam decreases with increasing the propagation distance whether parameterfωis large or small, and the larger the elliptic coefficientαis, the faster the peak intensity value decreases. These characteristics of vectorial elliptical Gaussian beam might find applications in modern optics.

scholarly journals Effects of Turbulent Atmosphere on the Propagation Properties of Vortex Hermite-cosine-hyperbolic-Gaussian Beams

2021 ◽  
Author(s):  
Zoubir Hricha ◽  
Mohammed Lazrek ◽  
Mohammed Yaalou ◽  
Abdelmajid Belafhal
Keyword(s):  
Turbulent Atmosphere ◽  
Analytical Formula ◽  
Propagation Distance ◽  
Central Peak ◽  
Average Intensity ◽  
Practical Applications ◽  
Diffraction Integral ◽  
Peak Intensity ◽  
Beam Parameters ◽  
Propagation Properties

Abstract The propagation properties of a vortex Hermite-cosh-Gaussian beam (vHChGB) in atmospheric turbulence are investigated based on the extended Huygens–Fresnel diffraction integral and Rytov method. The analytical formula for the average intensity of a vHChGB propagating in turbulent atmosphere is derived in detail. The influence of the turbulence strength on the intensity distribution under the change of beam parameters conditions is illustrated numerically and discussed. Results show the profile of the initial vHChGB remains unchanged within small propagation distance range, and at certain propagation distance a central peak intensity appears, and finally the beam evolves into Gaussian profile–like in far-field. The rising speed of the central peak intensity is faster when the turbulence strength is larger or the beam parameters such as the beam order, the vortex charge and the Gaussian waist width are smaller. With a small decentered parameter b, the beam profile changes faster as the wavelength is larger, whereas the reverse behavior occurs when b is large. The obtained results may be useful for the practical applications of vHChGB in optical communications and remote sensing.

scholarly journals Propagation of Optical Coherence Vortex Lattices in Turbulent Atmosphere

2018 ◽  
Vol 8 (12) ◽  
pp. 2476 ◽  
Author(s):  
Yan Huang ◽  
Yangsheng Yuan ◽  
Xianlong Liu ◽  
Jun Zeng ◽  
Fei Wang ◽  
...  
Keyword(s):  
Gaussian Beam ◽  
Optical Communications ◽  
Turbulent Atmosphere ◽  
Optical Coherence ◽  
Negative Effects ◽  
Beam Spot ◽  
Vortex Lattices ◽  
Beam Array ◽  
Convolution Approach ◽  
Propagation Properties

Propagation properties in the turbulence atmosphere of the optical coherence vortex lattices (OCVLs) are explored by the recently developed convolution approach. The evolution of spectral density distribution, the normalized M 2 -factor, and the beam wander of the OCVLs propagating through the atmospheric turbulence with Tatarskii spectrum are illustrated numerically. Our results show that the OCVLs display interesting propagation properties, e.g., the initial Gaussian beam distribution will evolve into hollow array distribution on propagation and finally becomes a Gaussian beam spot again in the far field in turbulent atmosphere. Furthermore, the OCVLs with large topological charge, large beam array order, large relative distance, and small coherence length are less affected by the negative effects of turbulence. Our results are expected to be used in the complex system optical communications.

scholarly journals Propagations of Sin-Gaussian Beam with Astigmatism through Oceanic Turbulence

2021 ◽  
Vol 299 ◽  
pp. 03013
Author(s):  
Kaicheng Zhu ◽  
Chang Gao ◽  
Jiahui Li ◽  
Dengjuan Ren ◽  
Jie Zhu
Keyword(s):  
Gaussian Beam ◽  
Coherence Length ◽  
Structure Constant ◽  
Average Intensity ◽  
Oceanic Water ◽  
Fresnel Integral ◽  
Oceanic Turbulence ◽  
Atmosphere Turbulence ◽  
Beam Parameters ◽  
Analytical Expressions

The propagation behaviours of a sin-Gaussian beam (SiGB) with astigmatism in oceanic water is analysed. The analytical expressions for the average intensity of such a beam are derived by using the extended Huygens-Fresnel integral. Its average intensity and on-axial intensity distributions in oceanic water are numerically examined. Then, we mainly focus on the effect of the beam parameters and the medium structure constant on the propagation behaviours for the astigmatic SiGBs in oceanic water, revealing that the evolutions of the intensity distributions can be effectively modulated by adjusting the astigmatic parameter, coherence length and the atmosphere turbulence strength.

scholarly journals Propagation of Vortex Cosine-hyperbolic-gaussian Beams in Atmospheric Turbulence

2021 ◽  
Author(s):  
Zoubir Hricha ◽  
Mohammed Lazrek ◽  
Mohammed Yaalou ◽  
Abdelmajid Belafhal
Keyword(s):  
Atmospheric Turbulence ◽  
Propagation Distance ◽  
Central Peak ◽  
Average Intensity ◽  
Gaussian Width ◽  
Diffraction Integral ◽  
Constant Strength ◽  
Beam Parameters ◽  
Propagation Properties ◽  
Rytov Method

Abstract In this paper, the propagation properties of a vortex cosh-Gaussian beam (vChGB) in turbulent atmosphere are investigated. Based on the extended Huygens–Fresnel diffraction integral and the Rytov method, the analytical expression for the average intensity of the vChGB propagating in the atmospheric turbulence is derived. The effects of the turbulent strength and the beam parameters on the intensity distribution and the beam spreading are illustrated numerically and analyzed in detail. It is shown that upon propagating, the incident vChGB keeps its initial hollow dark profile within a certain propagation distance, then the field loses gradually its central hole-intensity and transformed into a Gaussian–like beam for large propagation distance. The rising speed of the central peak is demonstrated to be faster when the constant strength turbulence or the wavelength are larger and the Gaussian width is smaller. The obtained results can be beneficial for applications in optical communications and remote sensing.

Propagation and self-healing properties of Lommel-Gaussian beam through atmospheric turbulence

2021 ◽  
Vol 17 (9) ◽  
pp. 572-576
Author(s):  
Xiang Chen ◽  
Yabo Yuan ◽  
Baoluo Yan ◽  
Ruoyu Zhang ◽  
Haifeng Liu ◽  
...  
Keyword(s):  
Gaussian Beam ◽  
Atmospheric Turbulence ◽  
Self Healing

scholarly journals Method for Measuring the Second-Order Moment of Atmospheric Turbulence

Atmosphere ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 564
Author(s):  
Hong Shen ◽  
Longkun Yu ◽  
Xu Jing ◽  
Fengfu Tan
Keyword(s):  
Atmospheric Turbulence ◽  
Weighting Function ◽  
Structure Constant ◽  
Turbulence Models ◽  
Second Order ◽  
Index Structure ◽  
Order Moment ◽  
Site Testing ◽  
Optical Effects ◽  
Novel Method

The turbulence moment of order m (μm) is defined as the refractive index structure constant Cn2 integrated over the whole path z with path-weighting function zm. Optical effects of atmospheric turbulence are directly related to turbulence moments. To evaluate the optical effects of atmospheric turbulence, it is necessary to measure the turbulence moment. It is well known that zero-order moments of turbulence (μ0) and five-thirds-order moments of turbulence (μ5/3), which correspond to the seeing and the isoplanatic angles, respectively, have been monitored as routine parameters in astronomical site testing. However, the direct measurement of second-order moments of turbulence (μ2) of the whole layer atmosphere has not been reported. Using a star as the light source, it has been found that μ2 can be measured through the covariance of the irradiance in two receiver apertures with suitable aperture size and aperture separation. Numerical results show that the theoretical error of this novel method is negligible in all the typical turbulence models. This method enabled us to monitor μ2 as a routine parameter in astronomical site testing, which is helpful to understand the characteristics of atmospheric turbulence better combined with μ0 and μ5/3.

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