Browsing by Author "Yuan, Yangsheng"

Now showing 1 - 8 of 8

Citation - WoS: 53
Citation - Scopus: 58
Average intensity and spreading of an elegant Hermite-Gaussian beam in turbulent atmosphere
(Optical Soc Amer, 2009) Yuan, Yangsheng; Cai, Yangjian; Qu, Jun; Eyyuboglu, Halil T.; Baykal, Yahya; 7688; 7812; Elektronik ve Haberleşme Mühendisliği; Elektrik-Elektronik Mühendisliği
The propagation of an elegant Hermite-Gaussian beam (EHGB) in turbulent atmosphere is investigated. Analytical propagation formulae for the average intensity and effective beam size of an EHGB in turbulent atmosphere are derived based on the extended Huygens-Fresnel integral. The corresponding results of a standard Hermite-Gaussian beam (SHGB) in turbulent atmosphere are also derived for the convenience of comparison. The intensity and spreading properties of EHGBs and SHGBs in turbulent atmosphere are studied numerically and comparatively. It is found that the propagation properties of EHGBs and SHGBs are much different from their properties in free space, and the EHGB and SHGB with higher orders are less affected by the turbulence. What's more, the SHGB spreads more rapidly than the EHGB in turbulent atmosphere under the same conditions. Our results will be useful in long-distance free-space optical communications. (C) 2009 Optical Society of America
Citation - WoS: 5
Citation - Scopus: 6
Effect of spatial coherence on the scintillation properties of a dark hollow beam in turbulent atmosphere
(Springer Heidelberg, 2013) Yuan, Yangsheng; Chen, Yahong; Liang, Chunhao; Cai, Yangjian; Baykal, Yahya; 7812; Elektrik-Elektronik Mühendisliği
With the help of a tensor method, we derive an explicit expression for the on-axis scintillation index of a circular partially coherent dark hollow (DH) beam in weakly turbulent atmosphere. The derived formula can be applied to study the scintillation properties of a partially coherent Gaussian beam and a partially coherent flat-topped (FT) beam. The effect of spatial coherence on the scintillation properties of DH beam, FT beam and Gaussian beam is studied numerically and comparatively. Our results show that the advantage of a DH beam over a FT beam and a Gaussian beam for reducing turbulence-induced scintillation increases particularly at long propagation distances with the decrease of spatial coherence or the increase of the atmospheric turbulence, which will be useful for long-distance free-space optical communications.
Citation - WoS: 133
Citation - Scopus: 147
M-2-factor of coherent and partially coherent dark hollow beams propagating in turbulent atmosphere
(Optical Soc Amer, 2009) Yuan, Yangsheng; Cai, Yangjian; Qu, Jun; Eyyuboglu, Halil T.; Bayka, Yahya; Korotkova, Olga; 7688; 7812; Elektronik ve Haberleşme Mühendisliği; Elektrik-Elektronik Mühendisliği
Analytical formula is derived for the M-2-factor of coherent and partially coherent dark hollow beams (DHB) in turbulent atmosphere based on the extended Huygens-Fresnel integral and the second-order moments of the Wigner distribution function. Our numerical results show that the M-2-factor of a DHB in turbulent atmosphere increases on propagation, which is much different from its invariant properties in free-space, and is mainly determined by the parameters of the beam and the atmosphere. The relative M-2-factor of a DHB increases slower than that of Gaussian and flat-topped beams on propagation, which means a DHB is less affected by the atmospheric turbulence than Gaussian and flat-topped beams. Furthermore, the relative M-2-factor of a DHB with lower coherence, longer wavelength and larger dark size is less affected by the atmospheric turbulence. Our results will be useful in long-distance free-space optical communications. (C) 2009 Optical Society of America
Citation - WoS: 36
Citation - Scopus: 40
Propagation factor of partially coherent flat-topped beam array in free space and turbulent atmosphere
(Elsevier Sci Ltd, 2012) Yuan, Yangsheng; Cai, Yangjian; Eyyuboglu, Halil T.; Baykal, Yahya; Chen, Jun; 7688; 7812; Elektronik ve Haberleşme Mühendisliği; Elektrik-Elektronik Mühendisliği
Analytical expressions for the propagation factor of partially coherent radial flat-topped (FT) beam array in free-space and turbulent atmosphere are derived. Our formulae can be applied to study the beam propagation factors of partially coherent Gaussian beam, partially coherent FT beam and partially coherent radial Gaussian beam array. The evolution properties of the propagation factors of those beams in turbulent atmosphere are studied numerically and comparatively. From the aspect of the propagation factor, our results show that partially coherent radial FT beam array is less affected by turbulence than partially coherent Gaussian beam, partially coherent FT beam and partially coherent radial Gaussian beam array. (C) 2011 Elsevier Ltd. All rights reserved.
Citation - WoS: 25
Citation - Scopus: 33
Propagation factors of Hermite-Gaussian beams in turbulent atmosphere
(Elsevier Sci Ltd, 2010) Yuan, Yangsheng; Cai, Yangjian; Qu, Jun; Eyyuboglu, Halil T.; Baykal, Yahya; 7688; 7812; Elektronik ve Haberleşme Mühendisliği; Elektrik-Elektronik Mühendisliği
Based on the extended Huygens-Fresnel integral and the second-order moments of the Wigner distribution function, an analytical formulae for the propagation factors (M-2-factors) of coherent and partially coherent one-dimensional Hermite-Gaussian beams in a turbulent atmosphere are derived. Evolution properties of the M-2-factor of the Hermite-Gaussian beam in a turbulent atmosphere are studied numerically in detail. Our results show that the M-2-factor of the Hermite-Gaussian beam increases upon propagation in a turbulent atmosphere. The M-2-factor of the Hermite-Gaussian beam with larger beam order (or lower coherence) increases slower that of the Hermite-Gaussian beam with smaller beam order (or higher coherence) in a turbulent atmosphere, which means that the Hermite-Gaussian beam with a larger beam order and lower coherence is less affected by a turbulent atmosphere. Our results will be useful in long-distance free-space optical communications. (c) 2010 Elsevier Ltd. All rights reserved.
Citation - WoS: 19
Citation - Scopus: 20
Propagation factors of laser array beams in turbulent atmosphere
(Taylor & Francis Ltd, 2010) Yuan, Yangsheng; Cai, Yangjian; Zhao, Chengliang; Eyyuboglu, Halil T.; Baykal, Yahya; 7688; 7812; Elektronik ve Haberleşme Mühendisliği; Elektrik-Elektronik Mühendisliği
The propagation factors of phased locked laser array beams of radial and rectangular symmetries in a turbulent atmosphere are investigated based on the extended Huygens-Fresnel integral and the Wigner distribution function. Analytical propagation formulae for the propagation factors are derived and numerical examples are illustrated. We find that unlike their propagation invariant properties in free space, the propagation factors of laser array beams increase when propagating in turbulent atmosphere, and are closely related to the parameters of initial beams and the atmosphere.
Citation - WoS: 86
Citation - Scopus: 93
Scintillation index of a multi-Gaussian Schell-model beam in turbulent atmosphere
(Elsevier, 2013) Yuan, Yangsheng; Liu, Xianlong; Wang, Fei; Chen, Yahong; Cai, Yangjian; Qu, Jun; Eyyuboglu, Halil T.; 7688; Elektronik ve Haberleşme Mühendisliği
Multi-Gaussian Schell-model (MGSM) beam was introduced recently [Sahin and Korotkova, Opt. Lett. 37 (2012) 2970; Korotkova et al., J. Opt. Soc. Am. A 29 (2012) 2159]. In this paper, an explicit expression for the scintillation index of a multi-Gaussian Schell-model (MGSM) beam in weakly or extremely strong turbulent atmosphere is derived with the help of a tensor method. Applying the derived formulae, the scintillation properties of a MGSM beam and a GSM beam in weakly or extremely strong turbulent atmosphere are studied numerically and comparatively. Our results show that a MGSM beam has advantage over a GSM beam for reducing turbulence-induced scintillation, which will be useful for long-distance free-space optical communications. (C) 2013 Elsevier B.V. All rights reserved.
Citation - WoS: 7
Citation - Scopus: 8
Scintillation properties of a truncated flat-topped beam in a weakly turbulent atmosphere
(Elsevier Sci Ltd, 2013) Liu, Xianlong; Liang, Chunhao; Yuan, Yangsheng; Cai, Yangjian; Eyyuboglu, Halil T.; 7688; Elektronik ve Haberleşme Mühendisliği
We derive derive an explicit expression for the scintillation index of a truncated flat-topped (FT) beam in a weakly turbulent atmosphere. Under suitable conditions, the derived formula reduces to the expression for the scintillation index of a FT beam or Gaussian beam without truncation. The scintillation properties of a truncated FT beam in a weakly turbulent atmosphere are illustrated numerically. It is found that the truncation parameter has strong influence on the scintillation properties, and the advantage of a FT beam over a Gaussian beam for reducing the negative influence of turbulence disappears gradually as the truncation parameter decreases. (C) 2012 Elsevier Ltd. All rights reserved.