Electromagnetic modelization of certain nano-optical systems

تاريخ النشر (نص حر)
2016
مدى
1 item
الموضوع
نوع الرسالة الجامعية
Thesis(M.A.)-Umm Al Qura University, Faculty of Applied Sciences, Department of physics, 1437.
الملخص

Abstract In recent years, optical technology and photonics industry developed fast, but further progress became difficult due to a fundamental limit of light known as the diffraction limit. This limit could be overcomed by using the novel technology of nano-optics or nano-photonics in which the size of the electromagnetic field is decreased down to the nano-scale and is used as a carrier for signal transmission, processing, and fabrication. Among those systems we focus our interest on the nano-photonic crystals (PhCs) which are periodic, optical nanostructures represented by natural or artificial structures with periodic modulation of the refractive index. In this thesis, we present a quantitative study of the photonic crystals, in- one and - two dimensions, with higher symmetry (including the dispersion of the nano-systems). The theoretical treatment of PhCs could be done by different numerical techniques, using matlab program, as Plane wave expansion method, Finite difference time domain, Order-n spectral method…etc. In this work we examine one of the numerical methods for photonic crystal analysis, the FDTD. As application we study a design of dielectric Bragg mirror (DBM) to achieve high reflectivity. We used dielectric materials silicon dioxide (SiO2, known as fused silica) and titanium dioxide (TiO2) arranged as a periodic stacks to design Bragg mirrors using the silicon dioxide as a substrate. DBRs can be regarded as one dimensional photonic crystal with a high reflectivity stop band. We adopted the transfer matrix method to calculate the reflectivity spectrum of multi-layered dielectric films, with a controlled reflectivity and dispersion in the wavelength range 600 - 1400 nm, and showed it exhibits a reflectivity of > 99.99 % around 1000 nm.