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Effect of beam types on the scintillations: A review

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dc.contributor.author Baykal, Yahya
dc.contributor.author Eyyuboğlu, Halil T.
dc.contributor.author Cai, Yangjian
dc.date.accessioned 2020-04-02T20:35:30Z
dc.date.available 2020-04-02T20:35:30Z
dc.date.issued 2009
dc.identifier.citation Baykal, Yahya; Eyyuboğlu, Hal,l T., "Effect of beam types on the scintillations: A review", Atmospheric Propagation Of Electromagnetic Waves III, Vol.7200, (2009). tr_TR
dc.identifier.isbn 978-0-8194-7446-9
dc.identifier.issn 0277-786X
dc.identifier.uri http://hdl.handle.net/20.500.12416/2866
dc.description.abstract When different incidences are launched in atmospheric turbulence, it is known that the intensity fluctuations exhibit different characteristics. In this paper we review our work done in the evaluations of the scintillation index of general beam types when such optical beams propagate in horizontal atmospheric links in the weak fluctuations regime. Variation of scintillation indices versus the source and medium parameters are examined for flat-topped-Gaussian, cosh-Gaussian, cos-Gaussian, annular, elliptical Gaussian, circular (i.e., stigmatic) and elliptical (i.e., astigmatic) dark hollow, lowest order Bessel-Gaussian and laser array beams. For flat-topped-Gaussian beam, scintillation is larger than the single Gaussian beam scintillation, when the source sizes are much less than the Fresnel zone but becomes smaller for source sizes much larger than the Fresnel zone. Cosh-Gaussian beam has lower on-axis scintillations at smaller source sizes and longer propagation distances as compared to Gaussian beams where focusing imposes more reduction on the cosh-Gaussian beam scintillations than that of the Gaussian beam. Intensity fluctuations of a cos-Gaussian beam show favorable behaviour against a Gaussian beam at lower propagation lengths. At longer propagation lengths, annular beam becomes advantageous. In focused cases, the scintillation index of annular beam is lower than the scintillation index of Gaussian and cos-Gaussian beams starting at earlier propagation distances. Cos-Gaussian beams are advantages at relatively large source sizes while the reverse is valid for annular beams. Scintillations of a stigmatic or astigmatic dark hollow beam can be smaller when compared to stigmatic or astigmatic Gaussian, annular and flat-topped beams under conditions that are closely related to the beam parameters. Intensity fluctuation of an elliptical Gaussian beam can also be smaller than a circular Gaussian beam depending on the propagation length and the ratio of the beam waist size along the long axis to that along the short axis (i.e., astigmatism). Comparing against the fundamental Gaussian beam on equal source size and equal power basis, it is observed that the scintillation index of the lowest order Bessel-Gaussian beam is lower at large source sizes and large width parameters. However, for excessively large width parameters and beyond certain propagation lengths, the advantage of the lowest order Bessel-Gaussian beam seems to be lost. Compared to Gaussian beam, laser array beam exhibits less scintillations at long propagation ranges and at some midrange radial displacement parameters. When compared among themselves, laser array beams tend to have reduced scintillations for larger number of beamlets, longer wavelengths, midrange radial displacement parameters, intermediate Gaussian source sizes, larger inner scales and smaller outer scales of turbulence. The number of beamlets used does not seem to be so effective in this improvement of the scintillations. tr_TR
dc.language.iso eng tr_TR
dc.publisher Spie-Int Soc Optical Engineering tr_TR
dc.relation.isversionof 10.1117/12.811848 tr_TR
dc.rights info:eu-repo/semantics/closedAccess tr_TR
dc.subject Atmospheric Turbulence tr_TR
dc.subject General Beams tr_TR
dc.subject Atmospheric Optics Telecommunication Links tr_TR
dc.subject Scintillations tr_TR
dc.title Effect of beam types on the scintillations: A review tr_TR
dc.type workingPaper tr_TR
dc.relation.journal Atmospheric Propagation Of Electromagnetic Waves III tr_TR
dc.contributor.authorID 7812 tr_TR
dc.contributor.authorID 7688 tr_TR
dc.identifier.volume 7200 tr_TR
dc.contributor.department Çankaya Üniversitesi, Mühendislik Fakültesi, Elektronik ve Haberleşme Mühendisliği Bölümü tr_TR


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