PubMed İndeksli Yayınlar Koleksiyonu

Permanent URI for this collectionhttps://hdl.handle.net/20.500.12416/8650

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Comparison of the Unmodified Rytov Method and the Modified Rytov Method in Obtaining Scintillations in Various Strongly Turbulent Media
(Optica Publishing Group (Formerly OSA), 2026) Baykal, Y.
The scintillation index as evaluated by the unmodified (classical) Rytov method solution for weak turbulence and evaluated by the modified or the extended Rytov method solution for strong turbulence is compared in different turbulent media, such as non-Kolmogorov atmospheric, non-Kolmogorov jet engine exhaust, marine atmospheric, and oceanic turbulences. When the scintillations are evaluated against the turbulence strength for various non-Kolmogorov power law and source sizes, the distinction between the modified Rytov and the unmodified Rytov method solutions, as the strength of turbulence increases, is clearly observed in all the turbulent media. This distinction is emphasized when the comparison is made at larger power law and source sizes. The results in this paper will be helpful in optical wireless communication system performance evaluations. © 2025 Optica Publishing Group.
Field Correlations in Jet Engine Exhaust Turbulence
(Optica Publishing Group (Formerly OSA), 2026) Baykal, Y.
Field correlations of collimated Gaussian beams are formulated and examined in jet engine exhaust turbulence. Variations of the field correlations are evaluated against the changes in the parameters of the wireless optical communication link and the jet engine exhaust turbulence. It is found that for all the link and turbulence parameters of interest, as the diagonal distance at the receiver plane increases, the field correlation decreases. Also, at the same diagonal distance from the receiver plane, field correlations tend to become smaller as the receiver points are at a larger distance from the receiver origin, at a smaller source size, wavelength, and inner scale values of jet engine exhaust turbulence. On the other hand, field correlations have a tendency to attain larger values at smaller link length, structure constant, amplitude coefficient for the additional high frequency spectrum area, outer scale of inhomogeneity, and the outer scale values of jet engine exhaust turbulence. © 2025 Optica Publishing Group. All rights, including for text and data mining (TDM), Artificial Intelligence (AI) training, and similar technologies, are reserved.
Field Correlations of a Gaussian Vortex Laser Beam in Vertical Turbulent Oceanic Links
(Optica Publishing Group (Formerly OSA), 2026) Gerçekcioǧlu, H.; Baykal, Y.
Utilizing the extended Huygens–Fresnel principle, field correlations of a Gaussian vortex beam propagating in the vertical turbulent oceanic link are examined analytically and evaluated by simulation in the Atlantic Ocean at low- and mid-latitude and high-latitude summer. Our formulation is based on the coherence length of a spherical wave operating at the depth range between 3000 and 3500 m. Variations in the rate of dissipation of turbulent kinetic energy per unit mass of fluid ε, the rate of dissipation of the mean-squared temperature χT, and the ratio of temperature to salinity contributions to the refractive index spectrum ω are taken into account at these depths in the underwater turbulent medium. The field correlation obtained using the coherence length found with the help of the depth-dependent power spectrum is expressed in detail. When the topological charge is selected considering the source size and propagation distance, it is seen that the normalized field correlation of the Gaussian vortex beam gives better results as compared to Gaussian beams. © 2025 Optica Publishing Group. All rights, including for text and data mining (TDM), Artificial Intelligence (AI) training, and similar technologies, are reserved.
Citation - WoS: 5
Citation - Scopus: 3
Intensity Fluctuations of Higher-Order Laser Modes in Jet Engine Exhaust Turbulence
(Optica Publishing Group, 2025) Baykal, Yahya Kemal
Intensity fluctuations quantified by the scintillation index are evaluated in jet engine exhaust turbulence when higher-order laser modes are used in optical wireless communication links. The jet engine exhaust turbulence power spectrum, modified by low-pass and high-pass filters, is employed. Intensity fluctuations are evaluated against the link length, structure constant, wave number (inverse of wavelength) (i.e., against turbulence strength), source size, and jet engine exhaust turbulence parameters. It is found that higher-order laser modes are better at mitigating the scintillations. Jet engine exhaust turbulence parameters are found to affect scintillations substantially. (c) 2025 Optica Publishing Group. All rights, including for text and data mining (TDM), Artificial Intelligence (AI) training, and similar technologies, are reserved.
Citation - WoS: 2
Citation - Scopus: 1
Propagation of Higher-Order Annular Gaussian Beams in Biological Tissues
(Optica Publishing Group, 2025) Arpali, Serap Altay; Baykal, Yahya Kemal
The propagation characteristics of a higher-order annular Gaussian (HOAG) beam in biological tissue turbulence are investigated. Average intensity at the receiver plane is found when the HOAG source field is used as excitation. The effects of the HOAG beam on different tissue types of the upper dermis (human), liver parenchyma (mouse), intestinal epithelium (mouse), and deep dermis (mouse) are studied. Variations of the average intensity versus the source and medium parameters such as the strength coefficient of the refractive-index fluctuations, propagation distance, wavelength, and beam size are presented. The results show that all modes of the HOAG beam can successively transmit beam energy at different levels of turbulence for all tissue types. At the same turbulence strength, HOAG beams having larger mode numbers transmit higher intensity to receivers than the modes with smaller mode orders, which is valid for all the examined tissue types. As the strength of tissue turbulence increases, the HOAG beam slowly turns into a pure Gaussian beam. For the different tissue types, the highest beam intensity at the receiver was observed for the deep dermis (mouse) tissue type. Despite the change in wavelength, refractive-index fluctuations, and source beam size, the highest beam transmission through the tissue in a turbulent environment was also observed for this same tissue type. This research may be useful in understanding the fundamentals of lighttissue interaction of HOAG laser beams, which may improve noninvasive disease detection and therapy methods through tissue in biophotonic technologies. (c) 2025 Optica Publishing Group. All rights, including for text and data mining (TDM), Artificial Intelligence (AI) training, and similar technologies, are reserved.

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Browsing PubMed İndeksli Yayınlar Koleksiyonu by Journal "Journal of the Optical Society of America A-Optics Image Science and Vision"