Browsing by Author "Eyyüboğlu, Halil Tanyer"

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Beam wander of J (0)- and I (0)-Bessel Gaussian beams propagating in turbulent atmosphere
(2010) Çil, Celal Zaim; Baykal, Yahya Kemal; Baykal, Yahya Kemal; Korotkova, O.; Cai, Y.; 7812
Root mean square (rms) beam wander of J (0)-Bessel Gaussian and I (0)-Bessel Gaussian beams, normalized by the rms beam wander of the fundamental Gaussian beam, is evaluated in atmospheric turbulence. Our formulation is based on the first and the second statistical moments obtained from the Rytov series. It is found that after propagating in atmospheric turbulence, the collimated J (0)-Bessel Gaussian and the I (0)-Bessel Gaussian beams have smaller rms beam wander than that of the Gaussian beam, regardless of the choice of Bessel width parameter. However, the extent of such an advantage depends on the chosen width parameter, Gaussian source size, propagation distance and the wavelength. Focusing at finite distances of the considered beams causes the rms beam wander to decrease sharply at the propagation distances equal to the focusing parameter.
Strong turbulence analysis of sinusoidal and hyperbolic Gaussian beams
(2010) Eyyüboğlu, Halil Tanyer; 7688
We formulate the on-axis asymptotic scintillations of sinusoidal and hyperbolic Gaussian beams, namely cos and cosh Gaussian beam, under strong turbulence conditions. Our results are displayed in the form of plots of the scintillation index against propagation distance and wavelength at several source and propagation parameters. It is revealed that at small source sizes, cosh Gaussian beams will exhibit the lowest scintillations, but at large source sizes, this will reverse and cos Gaussian beams will attain such characteristics. It is further found that in strong turbulence, longer wavelengths will offer less scintillations, a behavior similar to the one, encountered in weak scintillation conditions.