Scopus İndeksli Yayınlar Koleksiyonu

Permanent URI for this collectionhttps://hdl.handle.net/20.500.12416/8651

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Author: search.filters.author.Cai, YangjianPublisher: search.filters.publisher.Elsevier Science Bv

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Now showing 1 - 3 of 3
  • Article
    Citation - WoS: 15
    Citation - Scopus: 15
    Field Correlations of Annular Beams in Extremely Strong Turbulence
    (Elsevier Science Bv, 2012) Ji, Xiaoling; Baykal, Yahya; Cai, Yangjian
    The field correlations of annular beams are formulated when the atmosphere assumes extremely strong turbulence. Thicker and larger ring sized annular beams are found to exhibit larger absolute field correlations. For the same transverse distance at the receiver plane, annular beams attain larger field correlations if the transverse distance starts from the receiver origin. Comparisons of the annular beam absolute field correlations in extremely strong turbulence with the no turbulence results show that the absolute field correlation variations follow similar trends, except that the magnitudes of the absolute field correlations are much smaller in extremely strong turbulence and the annular fields become decorrelated at very short transverse distances. When the inner scale of turbulence becomes smaller, the absolute field correlations of the annular beams in extremely strong turbulence become smaller. (C) 2012 Elsevier B.V. All rights reserved.
  • Article
    Citation - WoS: 11
    Citation - Scopus: 11
    Non-Kolmogorov Spectrum Scintillation Aspects of Dark Hollow and Flat Topped Beams
    (Elsevier Science Bv, 2012) Eyyuboglu, Halil T.; Cai, Yangjian
    The scintillation aspects of dark hollow (DH) and fiat topped (FT) beams propagating in the turbulent atmosphere containing the non-Kolmogorov power spectrum are investigated. It is found that low scintillations will occur when the exponent of the power spectrum is just above the numeric value of 3. Initially, the rises in scintillations will take place as the exponent becomes larger, but later the scintillation reductions will be experienced as the exponent grows further, eventually minimum scintillations will be seen when the exponent has reached the value of 4. This will be the case, for scintillation variations against propagation distance, source size, wavelength, inner and outer scales of turbulence. Furthermore, it is found that at the small source sizes, DH beams will offer less scintillation than FT beams, while at the large source sizes, the reverse will be applicable. (C) 2011 Elsevier B.V. All rights reserved.
  • Article
    Citation - WoS: 16
    Citation - Scopus: 19
    Hypergeometric Gaussian Beam and Its Propagation in Turbulence
    (Elsevier Science Bv, 2012) Eyyuboglu, Halil Tanyer; Cai, Yangjian
    We study propagation characteristics of hypergeometric Gaussian beam in turbulence. In this context, we formulate the receiver plane intensity using extended Huygens-Fresnel integral. From the graphical results, it is seen that, after propagation, hypergeometric Gaussian will in general assume the shape of a dark hollow beam at topological charges other than zero. Increasing values of topological charge will make the beam broader with steeper walls. On the other hand, higher values of hollowness parameter will contract into a narrower shape. Raising the topological charge or the hollowness parameter individually will cause outer rings to appear. Both increased levels of turbulence and longer propagation distances will accelerate the beam evolution and help reach the final Gaussian shape sooner. At lower wavelengths, there will be less beam spreading. (C) 2012 Elsevier B.V. All rights reserved.