WoS İndeksli Yayınlar Koleksiyonu / WoS Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7150
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Conference Object Speckle Intensity Correlation Distribution Analysis Based on Coincidence Detection for Scattering Medium Characterization(IEEE, 2025) Dinleyici, Mehmet Salih; Kisa, Alperen; Atac, Enes; Karatay, Anil; Dinleyici, Mehmet Salih; 03.05. Department of Electrical and Electronics Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyCharacterizing a scattering medium is essential for understanding and controlling light propagation, enabling accurate imaging, correlation analysis, and material diagnostics in scientific applications. In this study, the scattering medium has been characterized by examining the spatial distribution of the second-order temporal correlation function of varying speckle patterns obtained under faint-light conditions using a charge-coupled device (CCD) camera. In the proposed method, the exposure time has been utilized as a self-coincidence circuit of the CCD. The spatial statistics of second-order temporal autocorrelation values have been analyzed through power spectral density and radial spatial autocorrelation function. The scattering degree of the medium has been determined using our proposed autocorrelation-based metric. The results from three different media have shown that the method is effective and holds potential for applications such as characterization through speckle imaging.Conference Object Citation - WoS: 1Citation - Scopus: 1Görgül kip ayrıştırması kullanılarak optik faz kırınımında hassasiyet iyileştirilmesi(IEEE, 2023) Dinleyici, Mehmet Salih; Dinleyici, Mehmet Salih; 03.05. Department of Electrical and Electronics Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyPhase diffraction is a potent property used in transparent dielectric film characterization. The measured diffraction pattern on the camera is evaluated by matching numerically computed diffraction patterns to determine the optical properties of the ultra-thin films (refractive index, thickness, etc.). However, the obtained diffraction data is not only a nonlinear and non-stationary signal but also exhibits micron-scale variations, thus limiting the measurement accuracy. Therefore, it is challenging to identify shifts in minima and deviations in amplitude on diffraction data to extract information about the optical properties of phase objects. In this study, it is aimed to improve the thickness sensitivity of the system by applying Empirical Mode Decomposition (EMD) to plane wave-based near-field phase diffraction data. Since EMD is very sensitive to abrupt changes in the signal due to the spatial frequency components, the nanoscale variations in the film thickness become more observable and detectable. Experimental outputs and numerical simulations show that the decomposition increases the thickness sensitivity comparing the classical matching technique.Conference Object Citation - WoS: 3Citation - Scopus: 4Düşük Maliyetli Serbest-uzay Optik İletişim Sistemi Tasarımı(Institute of Electrical and Electronics Engineers Inc., 2004) Karatay, Okan; Dinleyici, Mehmet Salih; Dinleyici, Mehmet Salih; 03.05. Department of Electrical and Electronics Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technologyhi recent years commercial and military interest in free-space optical communication (FSO) is growing due to the high bandwidths, portability and high security. Although the numerous advantages, atmospheric events such as attenuation and scintillation severely effects the link quality. Novel methods of mitigating atmospheric events were applied. Usage of large aperture lenses and high transmitted power according to decrease scintillation effects increases the system cost. Fresnel lenses, as an alternative to the classical optic system for mitigating scintillation effects would be a low-cost solution. As a result of the technological improvements on the output power and divergence angles of VSCEL (Vertical Cavity Surface Emitting Laser) enables high-speed cost effective FSO communication system design. In this research current applied FSO systems are analysed and fresnel lens optical system of alternative low-cost system designed.Conference Object Citation - Scopus: 1Lcd Arkaışık Modüllerinde Moire Etkisinin İncelenmesi(Institute of Electrical and Electronics Engineers Inc., 2007) Dinleyici, Mehmet Salih; Dinleyici, Mehmet Salih; Akın, Osman; 03.05. Department of Electrical and Electronics Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyLCD panellerde, Sıvı Kristal (Liquid Crystal) camdan önce parlak ve homojen bir ışık dağılımı elde etmek için LCD Arkaışık Modülünün içinde Dağıtıcı tabaka, Dağıtıcı filmler ve Parlaklık Arttırıcı Film (Brightness Enhancement Film – BEF) kullanılır. Ancak modülün en üstünde kullanılan dağıtıcı film, ışığı dağıtmanın ve BEF’i korumanın yanında Moire Etkisini önlemek için de kullanılabilir. Bu çalışmada, bahsi geçen bu son dağıtıcı filmin Moire etkisinin yokedilmesi konusundaki rolü incelendi.Conference Object A Study on Nonlinear Photonic Crystal Optical Switching With Chi((3)) Type Material(Institute of Electrical and Electronics Engineers Inc., 2009) Karakılınç, Özgür Önder; Dinleyici, Mehmet Salih; Dinleyici, Mehmet Salih; 03.05. Department of Electrical and Electronics Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyIn this study two dimensional square photonic crystal with line defect waveguide and embedded in nonlinear Kerr type dielectric rods are examined. Depending on the number and location of Kerr type nonlinear rods, power flux and harmonics are investigated. Optical switching of carrier signal is performed with using the control signal.Conference Object Kırınım Yöntemi Kullanılarak Zeytinyağındaki Tağşişin Belirlenmesi(Institute of Electrical and Electronics Engineers Inc., 2017) Ekici, Çağın; Dinleyici, Mehmet Salih; Dinleyici, Mehmet Salih; Ekici, Çağın; 01. Izmir Institute of Technology; 03.05. Department of Electrical and Electronics Engineering; 03. Faculty of EngineeringBu çalışmada, faz kırınım yöntemi kullanılarak gıda sanayisindeki büyük sorunlardan biri olan zeytinyağındaki tağşişin belirlenmesi amaçlanmıştır. Örnek sıvı içerisine ideal geometriye sahip fiber optik batırılarak lazer ışığının kırınımı incelenmiştir. Kırınım alanının matematiksel ifadesi Fresnel kırınım teorisine göre nümerik olarak hesaplanmıştır. Matematiksel modelleme, deneyler sonucunda elde edilen normalleştirilmiş kırınım deseniyle karşılaştırılıp, sıvının kırıcılık indisi tahmin edilmiştir. Kırınım yönteminin sıvının kırıcılık indisi tahminindeki yüksek hassasiyetli rolü (10−5 mertebesindeki) zeytinyağındaki tağşişin belirlenmesine imkan sağlamıştır.