Alireza Keshavarz
Department of Physics, Shiraz University of Technology, Shiraz, Iran
[ 1 ] - Designing the optimal Fresnel lenses by using Zemax software
In this paper, the optimal Fresnel lenses are designed by Zemax software.The fundamental problem of the Fresnel lenses is the beam divergence, which wasresolved by decreeing the output stain diameter on the image plane. For this purpose,two types of radial and cylindrical Fresnel lenses are simulated with different groovesusing Global and Hammer optimization methods. The minimum output stain di...
[ 2 ] - حالت‌های همدوس فوتون کاهیده برای نوسانگرهای ناهماهنگ در یک محیط غیرخطی کر
در این مقاله حالت‌های همدوس تعمیم‌یافته فوتون‌کاهیده برای نوسانگرهای ناهماهنگ در یک محیط غیرخطی کر معرفی شده است. سپس تابع ویگنر تعداد- فاز حالت‌های معرفی شده بررسی شده است. تابع ویگنر در بعضی از ناحیه‌ها منفی شده است که ماهیت غیرکلاسیکی این حالت‌ها را نشان می‌دهد. در نهایت ویژگی‌های فازی این حالت‌ها با استفاده از روشتابع توزیع فاز پگ- بارنت مورد بحث قرار گرفته است که نشان می‌دهد این تابع توزیع...
[ 3 ] - Numerical Calculation of Coupling Efficiency for an Elegant Hermite-Cosh-Gaussian Beams
The ABCD matrix method is used to simplifying the theoretical coupling efficiency calculation of Elegant Hermite-Cosh-Gaussian (EHChG) laser beams to a Single Mode Fiber (SMF) with a quadric lens formed on the tip. The integrals of coupling efficiency relation are calculated numerically by Boole method. Meanwhile, the structure parameters of surface-lensed fiber are optimized in numerical simul...
[ 4 ] - Transmission Properties of the Periodic Structures Based on Graphene Nonlinear Optical Conductivity in a Terahertz Field
By developing the terahertz (THz) technology, in addition to generators and detectors of THz waves, the existence of some tools such as modulators and filters are needed. THz filters are important tools for various applications in the field of chemical and biological sensors. Linear and nonlinear optical properties of the graphene have attracted lots of attention. In fact graphene exhibits vari...
[ 5 ] - Sensitivity Enhancement of Ring Laser Gyroscope Using Dielectric-Graphene Photonic Crystal
In a ring laser gyroscope, due to the rotation and the Sagnac effect, a phase difference between the two counter-propagating beams is generated. In this device, the higher phase difference between these two beams causes the better the interference pattern detection, and thus the sensitivity is increased. In this paper, the effect of inserting a dielectric-graphene photonic crystal inside a ring...
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