Average Intensity and Spreading of Partially Coherent Standard and Elegant Laguerre-Gaussian Beams in Turbulent Atmosphere

Abstract

Abstract-Analytical expressions for the average intensity, meansquared beam width and angular spread of partially coherent standard and elegant Laguerre-Gaussian (LG) beams propagating in turbulent atmosphere are derived. The properties of the average intensity, spreading and directionality of partially coherent standard and elegant LG beams in turbulent atmosphere are studied numerically and comparatively. It is found that the beam parameters and structure constant of turbulence together determine the properties of the beams in turbulent atmosphere. Partially coherent standard and elegant LG beams with smaller coherence length, larger beam orders and longer wavelength are less affected by the turbulence. A partially coherent elegant LG beam is less affected by turbulence than a partially coherent standard LG beam under the same condition. Furthermore, it is found that there exist equivalent partially coherent standard and elegant LG beams, equivalent fully coherent standard and elegant LG beams, equivalent Gaussian Schell-model beams that may have the same directionality as a fully coherent Gaussian beam both in free space and in turbulent atmosphere. Our results will be useful in long distance free-space optical communications.

Outage Probability and Bit-Error Rate for Communication Systems With Gaussian-Schell Electromagnetism Beams in Non-Kolmogorov Raining Turbulence

“…In order to mitigate the effects of atmospheric turbulence on FSO system, there have been various attempts using the multiple-input multiple-output (MIMO) technique [1,16,17]. Many methods have been proposed to overcome the turbulence-induced degradation of laser beams [2,[18][19][20]. However, there are critical defects of the log-normal distribution.…”

Scintillation Index of a Gaussian Schell-Model Beam on Slant Atmospheric Turbulence

“…We plot the logarithm of the ITU-R model Equation (19) in Figure 1 as a function of altitude for three values of the parameter C 2 n0 and three values of high-altitude wind speed. C 2 n0 affects the profile model only up to roughly 1 km, and high-altitude wind is the element most around altitudes of 10 km.…”

“…A few papers reported the scintillation of a partially coherent beam. Many researchers concerned with the spread and average intensity of partially coherent beam [18,19].…”

Average Intensity and Spreading of Partially Coherent Four-Petal Gaussian Beams in Turbulent Atmosphere

“…where D ψ is the wave structure function which is approximated by the phase structure function in Rytov's representations [20][21][22][23][24][25][26][27][28]54], ρ 0 = 0.545C 2 n k 2 z −3/5 is the spherical wave coherence length, C 2 n is the structure constant of local turbulent atmosphere. Substituting Eq.…”