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Wyszukujesz frazę "Kolmogorov turbulence" wg kryterium: Temat


Wyświetlanie 1-6 z 6
Tytuł:
Polarization properties of Gaussian–Schell model quantization field in a turbulent marine-atmosphere
Autorzy:
Zhao, Y.
Xia, M.
Wang, Q.
Li, Y.
Hu, Z.
Sun, H.
Zhang, Y.
Powiązania:
https://bibliotekanauki.pl/articles/173639.pdf
Data publikacji:
2016
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
polarization fluctuation
Gaussian–Schell model
marine-atmosphere
Kolmogorov turbulence
Opis:
Polarization properties of Gaussian–Schell model quantization field propagating through the Kolmogorov turbulence of a marine-atmosphere channel are studied based on the degree of quantum polarization. The effective photon annihilation and creation operators of Gaussian–Schell model quantization field propagation in a marine-atmosphere are developed by making use of the extended Huygens–Fresnel integral of quantum field. The effects of the outer scale on the degree of polarization can be neglected. As the source transverse coherent width, the number of received photons, the inner scale of turbulent eddies, and the source transverse radius decrease or the re- fractive index structure parameter increases, the degree of polarization decreases. In theory, we find that the polarization fade of marine-atmosphere turbulence channels is larger than that of terrene-atmosphere turbulence channels under same transport parameters and the channel with a stronger turbulence strength will possess a larger detection area of a polarization signal, which have potentially important implications for free-space quantum key distribution.
Źródło:
Optica Applicata; 2016, 46, 3; 335-345
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spectral degrees of cross-polarization of stochastic anisotropic electromagnetic beams in modified non-Kolmogorov atmospheric turbulence
Autorzy:
Chen, F.
Chen, J.
Zhao, Q.
Chen, Y
Xin, Y.
Li, J.
Pan, H.
Powiązania:
https://bibliotekanauki.pl/articles/174614.pdf
Data publikacji:
2013
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
quasi-homogenous source
modified non-Kolmogorov turbulence
generalized Stokes parameters
Opis:
Based on the extended Huygens–Fresnel principle, variations in generalized Stokes parameters of stochastic anisotropic electromagnetic beams propagating through modified non-Kolmogorov atmospheric turbulence have been analyzed. The changes in generalized Stokes parameters with different turbulence parameters and source parameters were analyzed first. After that, the distributions of the spectral degrees of cross-polarization (SDCP) of isotropic beams and anisotropic beams were simulated. The results show that the profiles of distribution of SDCP of these two kinds of beams are very different in the near field, and will fluctuate through the propagation in atmospheric turbulence, but at last, when the propagation distance is long enough, the difference in the source makes a slight difference in the final profiles of SDCP in the output plane. They mainly depended on the turbulence perturbation, and in the weak turbulence, the profiles of final distribution show more flatter features.
Źródło:
Optica Applicata; 2013, 43, 4; 773-783
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research on the propagation of partially coherent cosh-Gaussian beams through an ABCD optical system in non-Kolmogorov turbulence by effective tensor approach
Autorzy:
Ma, Hongjie
Li, Jinsong
Chen, Yueyang
Powiązania:
https://bibliotekanauki.pl/articles/1835756.pdf
Data publikacji:
2021
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
partially coherent
cosh-Gaussian beam
ABCD optical system
non-Kolmogorov turbulence
Opis:
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.
Źródło:
Optica Applicata; 2021, 51, 1; 147-158
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The polarization and coherence behavior of the flat-topped array beam through non-Kolmogorov turbulence
Autorzy:
Golmohammady, Shole
Ghafary, Bijan
Powiązania:
https://bibliotekanauki.pl/articles/173578.pdf
Data publikacji:
2019
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
non-Kolmogorov turbulence
flat-topped array laser beam
polarization
coherence
intensity distribution
Opis:
In the present paper, investigation on the polarization and coherence fluctuations of a flat-topped array beam in non-Kolmogorov atmospheric optics links has been presented. For this purpose, the spectral degree of polarization and coherence at the receiver plane is analytically formulated via the extended Huygens–Fresnel integral and the unified theory of polarization and coherence. The influences of the laser beam parameters and the power law exponent that describes the non-Kolmogorov spectrum of the statistical propagation properties of a partially coherent flat-topped array laser beam has been studied in detail. For the employed parameters, it can be concluded that the increase in the structure constant of turbulence (which is equivalent to the increase in turbulence strength) leads to a fast reduction in the spectral degree of coherence. Moreover, when the power law exponent is 3.1, the spectral degree of coherence exhibits a minimum value in comparison with the Kolmogorov atmospheric turbulence.
Źródło:
Optica Applicata; 2019, 49, 1; 75-88
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of inner and outer scale on beam spreading for a Gaussian wave propagating through anisotropic non-Kolmogorov turbulence
Autorzy:
Gao, C.
Li, X.
Powiązania:
https://bibliotekanauki.pl/articles/174609.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
anisotropy
Gaussian wave
long-term spreading radius
non-Kolmogorov turbulence
inner scales of turbulence
outer scales of turbulence
Opis:
Experimental results and empirical research have shown that atmospheric turbulence can present the anisotropic property not only at a few meters above the ground but also at high altitudes of up to several kilometers. This paper investigates beam spreading for a Gaussian wave propagating along a horizontal path in weak anisotropic non-Kolmogorov turbulence. Mathematical expressions for the long-term beam spreading radius were obtained based on the generalized von Kármán spectrum for anisotropic turbulence. The final model includes an anisotropic factor, which parameterizes the asymmetry of a turbulence cell, the spectral power law for non-Kolmogorov turbulence, the inner and outer scale of turbulence, and other essential optical parameters of a Gaussian wave. Numerical simulations indicate that the long-term beam spreading radius decreases with an increase in the anisotropic factor. We also analyze how the geometrical optics approximation may cause large errors for a small spectral power law value.
Źródło:
Optica Applicata; 2017, 47, 1; 63-74
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Changes in the states of polarization of random electromagnetic beams in atmospheric turbulence
Autorzy:
Li, J.
Zhao, K.
Lai, Y.
Powiązania:
https://bibliotekanauki.pl/articles/174110.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
non-Kolmogorov atmospheric turbulence
random electromagnetic beams
degree of polarization
orientation angle
degree of ellipticity
Opis:
Taking the random electromagnetic cosh-Gaussian beam as a typical example of random electromagnetic beams, the analytical expressions for the cross-spectral density matrix element of random electromagnetic cosh-Gaussian beams propagating through non-Kolmogorov atmospheric turbulence are derived, and used to study the changes in the states of polarization (degree of polarization, orientation angle and degree of ellipticity) of random electromagnetic cosh-Gaussian beams in non-Kolmogorov atmospheric turbulence. It is shown that the states of polarization of random electromagnetic cosh-Gaussian beams in non-Kolmogorov atmospheric turbulence are different from those in free space. The degree of polarization decreases, and the orientation angle and degree of ellipticity increase with increasing structure constant. The on-axis degree of polarization and the degree of ellipticity appear to have an oscillatory behavior and the orientation angle has a rapid transition for the larger cosh-part parameter of random electromagnetic cosh-Gaussian beams in atmospheric turbulence.
Źródło:
Optica Applicata; 2017, 47, 1; 51-62
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-6 z 6

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