Browsing by Author "Korotkova, Olga"

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Citation Count: Cai, Y., Korotkova, O., Eyyuboğlu,H.T., Baykal, Y. (2008). Active laser radar systems with stochastic electromagnetic beams in turbulent atmosphere. Optics Express, 16(20), 15834-15846. http://dx.doi.org/10.1364/OE.16.015834
Active laser radar systems with stochastic electromagnetic beams in turbulent atmosphere
(Optical Soc Amer, 2008) Cai, Yangjian; Korotkova, Olga; Eyyuboğlu, Halil T.; Baykal, Yahya; 7688; 7812
Propagation of stochastic electromagnetic beams through paraxial ABCD optical systems operating through turbulent atmosphere is investigated with the help of the ABCD matrices and the generalized Huygens-Fresnel integral. In particular, the analytic formula is derived for the cross-spectral density matrix of an electromagnetic Gaussian Schell-model (EGSM) beam. We applied our analysis for the ABCD system with a single lens located on the propagation path, representing, in a particular case, the unfolded double-pass propagation scenario of active laser radar. Through a number of numerical examples we investigated the effect of local turbulence strength and lens' parameters on spectral, coherence and polarization properties of the EGSM beam
Citation Count: Eyyuboglu, Halil T...et al. "Beam wander characteristics of flat-topped, dark hollow, cos and cosh-Gaussian, J(0)- and I-0- Bessel Gaussian beams propagating in turbulent atmosphere: A review", Atmospheric and Oceanic Propagation of Electromagnetic Waves Iv, Vol. 7588, (2010).
Beam Wander Characteristics of Flat-Topped, Dark Hollow, Cos and Cosh-Gaussian, J(0)- And I-0- Bessel Gaussian Beams Propagating In Turbulent Atmosphere: A Review
(Spie-Int Soc Optical Engineering, 2010) Eyyuboğlu, Halil T.; Baykal, Yahya; Çil, Celal Z.; Korotkova, Olga; Cai,Yangjian; 7812; 7688
In this paper we review our work done in the evaluations of the root mean square (rms) beam wander characteristics of the flat-topped, dark hollow, cos-and cosh Gaussian, J(0)-Bessel Gaussian and the I-0-Bessel Gaussian beams in atmospheric turbulence. Our formulation is based on the wave-treatment approach, where not only the beam sizes but the source beam profiles are taken into account as well. In this approach the first and the second statistical moments are obtained from the Rytov series under weak atmospheric turbulence conditions and the beam size are determined as a function of the propagation distance. It is found that after propagating in atmospheric turbulence, under certain conditions, the collimated flat-topped, dark hollow, cos-and cosh Gaussian, J(0)-Bessel Gaussian and the I-0-Bessel Gaussian beams have smaller rms beam wander compared to that of the Gaussian beam. The beam wander of these beams are analyzed against the propagation distance, source spot sizes, and against specific beam parameters related to the individual beam such as the relative amplitude factors of the constituent beams, the flatness parameters, the beam orders, the displacement parameters, the width parameters, and are compared against the corresponding Gaussian beam.
Citation Count: Çil, C.Z...et al. (2009). Beam wander of J (0)- and I (0)-Bessel Gaussian beams propagating in turbulent atmosphere. Applied Physisc B-Lasers And Optics, 98(1), 195-202. http://dx.doi.org/10.1007/s00340-009-3724-4
Beam wander of J (0)- and I (0)-Bessel Gaussian beams propagating in turbulent atmosphere
(Springer, 2010) Çil, Celal Zaim; Eyyuboğlu, Halil T.; Baykal, Yahya; Korotkova, Olga; Cai, Yangjian; 7688; 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
Citation Count: Cil, C. Z...et al. "Beam wander of J (0)- and I (0)-Bessel Gaussian beams propagating in turbulent atmosphere",Applied Physıcs B-Lasers and Optics, Vol. 98, No. 1, pp. 195-202, (2010).
Beam Wander of J (0)- and I (0)-Bessel Gaussian Beams Propagating In Turbulent Atmosphere
(Springer, 2010) Çil, Celal Zaim; Eyyuboğlu, Halil T.; Bykal, Yahya; Korotkova, Olga; Cai, Yangjian; 7812; 7688
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.
Citation Count: Tong, Z...et al. (2009). Correlation properties of random electromagnetic beams in laser resonators. Applied Physisc B-Lasers And Optics, 97(4), 849-857. http://dx.doi.org/10.1007/s00340-009-3629-2
Correlation properties of random electromagnetic beams in laser resonators
(Springer, 2009) Tong, Z.; Korotkova, Olga; Cai, Yangjian; Eyyuboğlu, Halil T.; Baykal, Yahya; 7688; 7812
With the help of the generalized Huygens-Fresnel principle and the tensor approach for electromagnetic stochastic beams we investigate the behavior of their two-point spatial correlation properties on interaction with a laser resonator. In particular, the evolution of the degree of coherence, of the degree of cross-polarization and of the intensity correlations (at one and two points in space) is analyzed for typical beams and cavities. The theory is illustrated by numerical curves pertaining to various correlation properties of typical electromagnetic Gaussian Schell-model beams
Citation Count: Yao, M...et al. (2008). Evolution of the degree of polarization of an electromagnetic Gaussian Schell-model. beam in a Gaussian cavity. Optics Letters, 33(19), 2266-2268. http://dx.doi.org/10.1364/OL.33.002266
Evolution of the degree of polarization of an electromagnetic Gaussian Schell-model. beam in a Gaussian cavity
(Optical Soc Amer, 2008) Yao, Min; Cai, Yangjian; Eyyuboğlu, Halil T.; Baykal, Yahya; Korotkova, Olga; 7688; 7812
The interaction of an electromagnetic Gaussian Schell-model (EGSM) beam with a Gaussian cavity is analyzed. In particular, the evolution of the degree of polarization of the EGSM beam is investigated. The results show that the behavior of the degree of polarization depends on both the statistical properties of the source that generates the EGSM beam and the parameter of the cavity
Citation Count: Eyyuboğlu, H.T...et al. (2008). Intensity fluctuations in J-Bessel-Gaussian beams of all orders propagating in turbulent atmosphere. Applied Physisc B-Lasers And Optics, 93(2-3), 605-611. http://dx.doi.org/10.1007/s00340-008-3230-0
Intensity fluctuations in J-Bessel-Gaussian beams of all orders propagating in turbulent atmosphere
(Springer, 2008) Eyyuboğlu, Halil T.; Sermutlu, Emre; Baykal, Yahya; Cai, Yangjian; Korotkova, Olga; 7688; 17647; 7812
The scintillation index of a J (n) -Bessel-Gaussian beam of any order propagating in turbulent atmosphere is derived and numerically evaluated at transverse cross-sections with the aid of a specially designed triple integral routine. The graphical outputs indicate that, just like the previously investigated J (0)-Bessel-Gaussian beam, higher-order members of the family also offer favorable scintillation characteristics at large source sizes. This advantage is maintained against rising beam orders. Viewed along the propagation axis, beams with lower orders and smaller widths exhibit smaller values of the scintillation index at shorter propagation distances and large values at longer propagation distances. Further, it is shown that the scintillation index of the J (n) -Bessel-Gaussian beams (n > 0) is larger than that of the fundamental Gaussian and the J (0)-Bessel-Gaussian beams only near the on-axis points, while remaining smaller towards the edges of the beam
Citation Count: Baykal, Y...et al. (2011). Intensity fluctuations of partially coherent cos Gaussian and cosh Gaussian beams in atmospheric turbulence. Journal of Optics, 13(5). http://dx.doi.org/10.1088/2040-8978/13/5/055709
Intensity fluctuations of partially coherent cos Gaussian and cosh Gaussian beams in atmospheric turbulence
(IOP Publishing Ltd, 2011) Baykal, Yahya; Eyyuboğlu, Halil T.; Çil, Celal Zaim; Cai, Yangjian; Korotkova, Olga; 7812; 7688
On-axis and off-axis scintillation indices of partially coherent collimated cos Gaussian and cosh Gaussian beams are evaluated on their propagation in a weakly turbulent atmosphere. In the coherent limits, our results are in quite good agreement with those for the existing Rytov scintillation index of coherent cos Gaussian and cosh Gaussian beams, especially for very small and very large sized beams and at weaker turbulence levels. The on-axis scintillation index becomes lower as the degree of source coherence decreases for both cos Gaussian and cosh Gaussian beams. Comparing to the partially coherent Gaussian beam on-axis scintillations, partially coherent cos Gaussian beam scintillations are generally lower and partially coherent cosh Gaussian beam scintillations are higher. Scintillations of Gaussian beams are very close to the scintillations of equal-power cos Gaussian and are quite similar to the scintillations of equal-power cosh Gaussian beams. Off-axis evaluations yield that the scintillations of both cos Gaussian and cosh Gaussian beams increase as the diagonal distance from the origin increases, being valid for all degrees of partial coherence
Citation Count: Yuan, Y...et al. (2009). M-2-factor of coherent and partially coherent dark hollow beams propagating in turbulent atmosphere. Optics Express, 17(20), 17344-17356. http://dx.doi.org/10.1364/OE.17.017344
M-2-factor of coherent and partially coherent dark hollow beams propagating in turbulent atmosphere
(Optical Society of America, 2009) Yuan, Yangsheng; Cai, Yangjian; Qu, Jun; Eyyuboğlu, Halil T.; Baykal, Yahya; Korotkova, Olga; 7688; 7812
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
Citation Count: Eyyuboğlu, H.T...et al. (2009). Scintillation index of modified Bessel-Gaussian beams propagating in turbulent media. Journal of the Optical Society of America A-Optics Image Science and Vision, 26(2), 387-394.
Scintillation index of modified Bessel-Gaussian beams propagating in turbulent media
(Optical Soc Amer, 2009) Eyyuboğlu, Halil T.; Baykal, Yahya; Sermutlu, Emre; Korotkova, Olga; Cai, Yangjian; 7688; 7812; 17647
The scintillation index is formulated for modified Bessel-Gaussian beams propagating in weakly turbulent media. Numerical calculations applied directly to the derived triple integral show that, for off-axis positions, the modified Bessel-Gaussian beams of higher than zero order scintillate less than Gaussian beams at large input beam sizes and low beam orders with the increasing width parameter initially contributing positively to this phenomenon of less scintillation. As the beam order exceeds two, this advantage is diminished. The modified Bessel-Gaussian beam of order zero is a special case, however, exhibiting lowest scintillation at small input beam sizes. When considered against the propagation length, higher-order modified Bessel-Gaussian beams continue to offer less scintillation than those of order zero. At various radial positions, the scintillation index of modified Bessel-Gaussian beams with orders higher than zero attains small values toward the beam edges but rises sharply when approaching the beam axis. The effect of inner and outer scales of turbulence is also studied, and it is found that while increasing the inner scale of turbulence seems to cause increases in scintillation, the influence of the outer scale is hardly noticeable
Citation Count: Korotkova, O...et al. (2008). State of polarization of a stochastic electromagnetic beam in an optical resonator. Journal of the Optical Society of America A-Optics Image Science and Vision, 25(11), 2710-2720. http://dx.doi.org/10.1364/JOSAA.25.002710
State of polarization of a stochastic electromagnetic beam in an optical resonator
(Optical Soc Amer, 2008) Korotkova, Olga; Yao, Min; Cai, Yangjian; Eyyuboğlu, Halil T.; Baykal, Yahya; 7688; 7812
On the basis of the unified theory of coherence and polarization, we investigate the behavior of the state of polarization of a stochastic electromagnetic beam in a Gaussian cavity. Formulations both in terms of Stokes parameters and in terms of polarization ellipse are given. We show that the state of polarization stabilizes, except in the case of a lossless cavity, after several passages between the mirrors, exhibiting monotonic or oscillatory behavior depending on the parameters of the resonator. We also find that an initially (spatially) uniformly polarized beam remains nonuniformly polarized even for a large number of passages between the mirrors of the cavity