خط مشی دسترسیدرباره ماپشتیبانی آنلاین
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Document Type:Latin Dissertation
Language of Document:English
Record Number:54760
Doc. No:TL24714
Call number:‭3342716‬
Main Entry:Mohammad Masud Siraj
Title & Author:Two dimensional photonic crystals with anisotropic constituents and their propagation characteristicsMohammad Masud Siraj
College:University of Dayton
Date:2008
Degree:Ph.D.
student score:2008
Page No:123
Abstract:Photonic crystals (PhCs) possess unique dispersion properties that can be exploited to enable novel photonic applications. These properties can also be used to significantly improve the performance of existing photonic devices. Many applications of PhCs such as waveguides, PC fibers and photonic cavities have been explored by using the presence of a photonic bandgap over a desired frequency range with a defect incorporated in the structure to allow only a desired mode to propagate. This strategy often requires a large index contrast between materials to create the band gap in the first place, which limits the materials that can be used for the photonic devices. On the other hand, many phenomena such as negative refraction, superprism, super-resolution, and slow light have been demonstrated based on unique spatial and temporal dispersion properties of a PhC and they are often observable with materials having a low index contrast. In my research we investigate self-collimation, another dispersion-related phenomenon of PhCs, that is manifested to some degree in all PhCs. In free space or homogeneous materials propagating electromagnetic waves spread due to diffraction effects, but a PhC in the region of self-collimation has essentially no diffraction and input beams spread over a range of input angles are collimated into a single direction. The phenomenon of beam-like propagation without divergence is important for many applications, including optical interconnects in an integrated circuit. Self-collimation provides a solution to beam control that does not require additional fabrication steps and can be used in conjunction with additional effects to further tailor the application needs. We develop a process to investigate the range of input angles and the degree of collimation of the beam inside the photonic crystal composed of anisotropic constituents. The optical properties of a photobleached 4-dimethylamino-N-methyl-4-stilbazolium-tosylate (DAST) crystal are used in our model to demonstrate the efficacy of the self-collimation features. In DAST we identified conditions where the divergence angle over a span of incident angles of 40 degrees can be less than 1 degree and the transmission remains high over the entire span of angles.
Subject:Pure sciences; Anisotropic; Photonic crystals; Self-collimation; Optics; 0752:Optics
Added Entry:J. W. Haus
Added Entry:University of Dayton