scholarly journals Influence of Source Parameters and Non-Kolmogorov Turbulence on Evolution Properties of Radial Phased-Locked Partially Coherent Vortex Beam Array

Photonics ◽  
2021 ◽  
Vol 8 (11) ◽  
pp. 512
Author(s):  
Jiao Wang ◽  
Mingjun Wang ◽  
Sichen Lei ◽  
Zhenkun Tan ◽  
Chenbai Wang ◽  
...  
Keyword(s):  
Gaussian Distribution ◽  
Intensity Distribution ◽  
Source Parameters ◽  
Propagation Distance ◽  
Average Intensity ◽  
Free Space Optical ◽  
Partially Coherent ◽  
Beam Array ◽  
Kolmogorov Turbulence ◽  
Coherent Vortex

Partially coherent optical vortices have been applicated widely to reduce the influence of atmospheric turbulence, especially for free-space optical (FSO) communication. Furthermore, the beam array is an effective way to increase the power of the light source, and can increase the propagation distance of the FSO communication system. Herein, we innovatively report evolution properties of the radial phased-locked partially coherent vortex (RPLPCV) beam array in non-Kolmogorov turbulence. The analytical expressions for the cross-spectral density and the average intensity of an RPLPCV beam array propagated through non-Kolmogorov turbulence are obtained. The numerical results reveal that the intensity distribution of the RPLPCV array propagated in the non-Kolmogorov turbulence is gradually converted to a standard Gaussian distribution. In addition, the larger the radial radius, radial number and waist radius are, the smaller the coherence length is. Moreover, the longer the wavelength is, the shorter the propagation distance required for the intensity distribution of the RPLPCV beam array to be converted into a Gaussian distribution in the non-Kolmogorov turbulence. The research in this paper provides a theoretical reference for the selection of light sources and the suppression of turbulence effects in wireless optical communication.

Evolution of Intensity Distribution of Partially Coherent Sinusoidal-Gaussian Beams through Slant Atmospheric Turbulence

2012 ◽  
Vol 263-266 ◽  
pp. 1214-1218 ◽  
Author(s):  
Jin Hong Li ◽  
Mei Ling Duan ◽  
Ji Lin Wei
Keyword(s):  
Atmospheric Turbulence ◽  
Intensity Distribution ◽  
Gaussian Beams ◽  
Free Space Optical ◽  
Partially Coherent ◽  
Atmospheric Propagation ◽  
Horizontal Path ◽  
Potential Applications ◽  
Slant Path ◽  
Analytical Expressions

Based on the extended Huygens-Fresnel principle, the analytical expressions for the intensity of partially coherent sinusoidal-Gaussian beams with Schell-model correlator in atmospheric turbulence along a slant path are derived, and used to study the evolution of intensity distribution of partially coherent sinusoidal-Gaussian beams, including partially coherent sin-Gaussian (SiG), cos-Gaussian (CoG), sinh-Gaussian (ShG), cosh-Gaussian (ChG) beams. It is shown that the different intensity distribution at the source plane of the four beams evolve to the same Gaussian distribution in atmospheric turbulence along a slant path. The spreading of the partially coherent sinusoidal-Gaussian beams along a horizontal path is larger than that along a slant path in the long atmospheric propagation, and the slant path is more beneficial to the beam propagation through atmospheric turbulence in comparison with the horizontal propagation. The validity of our results is interpreted physically. Results in this paper may provide potential applications in free-space optical communications.

scholarly journals Research on the propagation of partially coherent cosh-Gaussian beams through an ABCD optical system in non-Kolmogorov turbulence by effective tensor approach

2021 ◽  
Vol 51 (1) ◽  
Author(s):  
Hongjie Ma ◽  
Jinsong Li ◽  
Yueyang Chen
Keyword(s):  
Optical System ◽  
Coherence Length ◽  
Spatial Coherence ◽  
Structure Constant ◽  
Beam Propagation ◽  
Gaussian Beams ◽  
Average Intensity ◽  
Partially Coherent ◽  
Kolmogorov Turbulence ◽  
Abcd Optical System

An efficient tensor approach is used to study the propagation of partially coherent cosh-Gaussian beams through an ABCD optical system in non-Kolmogorov turbulence. Analytical expressions for the average intensity of the beam propagation are derived. The properties of the average intensity are investigated with a numerical example. One finds that the propagation of the beam with larger spatial coherence length is less affected by distance when the propagation distance is long enough, and as the Ch-parameter increases, the beam propagation is less effected by turbulent atmosphere. It is also found that the average intensity distribution of the cosh-Gaussian beams with larger spatial correlation length is more affected by the structure constant of turbulence (i.e., turbulence level). By choosing a suitable Ch-parameter and spatial coherence length, the partially coherent cosh-Gaussian beams can be better transmitted in non-Kolmogorov turbulence. Our results will be useful in free-space communication.

scholarly journals Intensity and Coherence Characteristics of a Radial Phase-Locked Multi-Gaussian Schell-Model Vortex Beam Array in Atmospheric Turbulence

Photonics ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 5
Author(s):  
Jialu Zhao ◽  
Guiqiu Wang ◽  
Xiaolu Ma ◽  
Haiyang Zhong ◽  
Hongming Yin ◽  
...  
Keyword(s):  
Atmospheric Turbulence ◽  
Optical Communication ◽  
Intensity Distribution ◽  
Free Space ◽  
Vortex Beam ◽  
Free Space Optical Communication ◽  
Free Space Optical ◽  
Beam Array ◽  
Space Optical Communication ◽  
Radial Phase

The theoretical descriptions for a radial phase-locked multi-Gaussian Schell-model vortex (RPLMGSMV) beam array is first given. The normalized intensity and coherence distributions of a RPLMGSMV beam array propagating in free space and atmospheric turbulence are illustrated and analyzed. The results show that a RPLMGSMV beam array with larger total number N or smaller coherence length σ can evolve into a beam with better flatness when the beam array translating into the flat-topped profile at longer distance z and the flatness of the flat-topped intensity distribution can be destroyed by the atmospheric turbulence at longer distance z. The coherence distribution of a RPLMGSMV beam array in atmospheric turbulence at the longer distance will have Gaussian distribution. The research results will be useful in free space optical communication using a RPLMGSMV beam array.

scholarly journals Tight Focusing of Partially Coherent Vortex Beams

2012 ◽  
Vol 2012 ◽  
pp. 1-6
Author(s):  
Rakesh Kumar Singh
Keyword(s):  
Intensity Distribution ◽  
Topological Charge ◽  
Incident Beam ◽  
Compact Form ◽  
Degree Of Polarization ◽  
Polarization Distribution ◽  
Partially Coherent ◽  
Tight Focusing ◽  
Coherent Vortex ◽  
Vortex Beams

Tight focusing of partially polarized vortex beams has been studied. Compact form of the coherence matrix has been derived for polarized vortex beams. Effects of topological charge and polarization distribution of the incident beam on intensity distribution, degree of polarization, and coherence have been investigated.

Structure images of Si, Ge and Mos2 crystals and some application to radiation damage studies

1978 ◽  
Vol 36 (1) ◽  
pp. 292-293 ◽  
Author(s):  
K. Izui ◽  
T. Nishida ◽  
S. Furuno ◽  
H. Otsu ◽  
S. Kuwabara
Keyword(s):  
Radiation Damage ◽  
Exposure Time ◽  
Gaussian Distribution ◽  
Intensity Distribution ◽  
Chromatic Aberration ◽  
Magnetic Lens

Recently we have observed the structure images of silicon in the (110), (111) and (100) projection respectively, and then examined the optimum defocus and thickness ranges for the formation of such images on the basis of calculations of image contrasts using the n-slice theory. The present paper reports the effects of a chromatic aberration and a slight misorientation on the images, and also presents some applications of structure images of Si, Ge and MoS2 to the radiation damage studies.(1) Effect of a chromatic aberration and slight misorientation: There is an inevitable fluctuation in the amount of defocus due to a chromatic aberration originating from the fluctuations both in the energies of electrons and in the magnetic lens current. The actual image is a results of superposition of those fluctuated images during the exposure time. Assuming the Gaussian distribution for defocus, Δf around the optimum defocus value Δf0, the intensity distribution, I(x,y) in the image formed by this fluctuation is given by

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