WoS İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12416/8653
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Article Citation - WoS: 1Scintillation Index in Non-Kolmogorov Jet Engine Exhaust Turbulence(IOP Publishing Ltd, 2026) Baykal, YahyaIn a non-Kolmogorov jet engine exhaust turbulence environment, scintillation index is found and evaluated. Effects of non-Kolmogorov turbulence spectrum, i.e., power law on the scintillations are studied. Variations of the scintillations against the change in the power law are found for various link lengths, structure constants, wave numbers, jet engine exhaust turbulence strengths, source sizes and scale parameters of jet engine exhaust turbulence. When the power law of non-Kolmogorov turbulence varies, the changes in the scintillations in jet engine exhaust turbulence are not large. The results in this paper could be of help to designers of optical wireless communication systems operating in atmosphere experiencing non-Kolmogorov jet engine exhaust turbulence.Article Transmittance of Gaussian Beam in Anisotropic Jet Engine Exhaust Turbulence(Pergamon-Elsevier Science Ltd, 2026) Baykal, YahyaTransmittance is a metric that provides information on how much of the intensity is transferred to the receiver for a given medium. One of the definitions of transmittance is the ratio of the average received intensity in the presence of turbulence to the received intensity in the absence of turbulence. Under such definition, transmittance is found in an anisotropic jet engine exhaust turbulent environment. For various receiver points, transmittances versus the wireless optical communication (WOC) link and anisotropic jet engine exhaust turbulence parameters are presented. The results are useful for designers of WOC links that are installed in the premises such as the airports that possess jet engine exhaust turbulence.Article Adaptive Optics Applied To the Scintillation Index in Tissues(Optica Publishing Group, 2025) Baykal, YahyaMitigation of the scintillation index of a collimated Gaussian beam, occurring in a turbulent tissue, is investigated by applying adaptive optics. Tilt and astigmatism types of adaptive optics corrections are applied, and the reduction in the tissue scintillations, referenced to no adaptive optics (No AO) scintillations, is reported for tilt only (T Only), astigmatism only (A Only), and total (T + A) adaptive optics correction. Reduction in the scintillations is analyzed against the tissue length, Gaussian laser beam source size, wavelength, receiver aperture diameter, and the tissue turbulence parameters, which are the strength coefficient of the refractive-index fluctuations, fractal dimension, characteristic length of heterogeneity, and small length-scale factor. Finally, the adaptive optics effect on the scintillations is reported for some specific tissue types of liver parenchyma (mouse), intestinal epithelium (mouse), and upper dermis (human). (c) 2025 Optica Publishing Group. All rights, including for text and data mining (TDM), Artificial Intelligence (AI) training, and similar technologies, are reserved.Article Citation - WoS: 1Citation - Scopus: 1Optical Wireless Sensor Networks in Underwater Turbulence Using Multimode Beams(Elsevier Sci Ltd, 2025) Baykal, YahyaOptical wireless sensor networks (OWSN) that employ multimode optical beams operating in underwater turbulence are investigated. For this purpose, off-axis average intensity at the destination point (receiver) is formulated in underwater turbulence when the incidences at the sensors are multimode optical beams. Based on the trends of the appropriately determined off-axis received average intensities of various multimode beams, identification of the sensor can be made. The proposed procedure is also applied as special cases, to optical wireless sensor networks that employ single higher mode beams.Article Citation - WoS: 4Citation - Scopus: 1Degradation of Signal-To Ratio Due To Turbulence in Various Biological Tissues(Iop Publishing Ltd, 2024) Baykal, YahyaWhen a biological tissue is excited by an optical beam, the presence of turbulence in the tissue causes the signal-to-noise ratio (SNR) to degrade. This degradation is in reference to the SNR value in the absence of tissue turbulence. The effect of tissue turbulence in reducing the SNR is examined. SNR reductions are examined for various types of biological tissues such as liver parenchyma (mouse), intestinal epithelium (mouse), upper dermis (human). Also, SNR reductions in the turbulent tissue are evaluated against the changes in the strength coefficient of the refractive-index fluctuations, fractal dimension, characteristic length of heterogeneity, small length-scale factor, tissue length, wavelength and the source size.Article Citation - WoS: 3Citation - Scopus: 3Field Correlations of a Partially Coherent Optical Gaussian Wave in Tissue Turbulence(Optica Publishing Group, 2022) Baykal, YahyaFor a partially coherent Gaussian optical wave, field correlations in turbulent tissues are examined. Changes in the field correlations are evaluated when the degree of source coherence, diagonal length from the receiver point, transverse receiver coordinate, tissue type, tissue length, source size, characteristic length of heterogeneity, strength coefficient of the refractive-index fluctuations, fractal dimension, and the small length-scale factor of the turbulent tissue vary. Investigated turbulent tissue types are liver parenchyma (mouse), upper dermis (human), intestinal epithelium (mouse), and deep dermis (mouse). For all the examined tissue types, field correlations are found to increase as the degree of source coherence, fractal dimension, and small length-scale factor increase and as the diagonal length from the receiver point, transverse receiver coordinate, tissue length, characteristic length of heterogeneity, and strength coefficient of the refractive-index fluctuations decrease. For the coherent source, an increase in the source size will increase the field correlations; however, for the partially coherent source, this trend is reversed. (c) 2022 Optica Publishing GroupArticle Citation - WoS: 7Citation - Scopus: 6Adaptive Optics Correction of Beam Spread in Biological Tissues(Pergamon-elsevier Science Ltd, 2022) Baykal, YahyaBeam spread in turbulent biological tissues is examined when the tissue is excited with a collimated Gaussian laser beam. Adaptive optics correction is applied to the beam spread in the form of piston only (P Only), tilt only (T Only), piston + tilt (P + T), and the reduction in the beam spread is evaluated as com-pared to the no adaptive optics (No AO) corrected beam spread. No AO and adaptive optics corrected beam spread are expressed for various biological tissue types, against the variations in the strength co-efficient of the refractive-index fluctuations, source size, small length-scale factor of turbulence, tissue length, fractal dimension, characteristic lengths of heterogeneity and the wavelength. For the examined tissue types of liver parenchyma (mouse), intestinal epithelium (mouse), upper dermis (human) and deep dermis (mouse), No AO beam spread and the adaptive optics corrected beam spread are found to increase as the strength coefficient of the refractive-index fluctuations, tissue length, fractal dimension, the char-acteristic lengths of heterogeneity increase, and to decrease as the source size, small length-scale factor, wavelength increase. Reduction ratio of P + T correction is almost the same for all the evaluated cases which is 74%.(C) 2022 Elsevier Ltd. All rights reserved.Editorial Citation - WoS: 1Citation - Scopus: 1Editorial: Optical Wave Propagation and Communication in Turbulent Media(Frontiers Media Sa, 2023) Baykal, YahyaArticle Citation - WoS: 6Citation - Scopus: 6Intensity Correlation of Collimated Gaussian Beams Propagating in Biological Tissues(Taylor & Francis Ltd, 2021) Baykal, YahyaIntensity correlations in turbulent biological tissues are evaluated when collimated Gaussian laser beam is used. Variations of the intensity correlations in biological tissues are investigated versus the diagonal distance from the origin of the observation plane for various tissue distances, biological tissue types, strength coefficients of the refractive-index fluctuations, starting points at the observation plane. Also, intensity correlations in biological tissues for various biological tissue types versus the strength coefficient of the refractive-index fluctuations, small length-scale factor, fractal dimension. It is found that intensity correlations become smaller at larger diagonal distance, tissue distance, strength coefficients of the refractive-index fluctuations, and at smaller source size, small length-scale factor and fractal dimensions. Behaviour of the intensity correlations is found to depend on the type of the biological tissue. Our results can be used in tissue identification and to find the disorders in biological tissues.