الفهرس 
AbstractOnly 14 pages are availabe for public view
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Abstract
Polarization is a fundamental property of electromagnetic waves that transmits information in signal transmission and sensitive measurements. The optical communication systems suffer from the polarization conversion during the transmission of huge quantities of data from the transmitter to the receiver. Traditional methods for enhanced polarization control place high demands on material properties and achieve only limited success. In order to overcome the problems associated to the polarization conversion, polarization converters have been investigated based on plasmonic devices. Plasmonic devices provide better performance than traditional systems in terms of size, weight, cost, and power consumption. Due to the amazing characteristics of surface plasmons, several plasmonic devices, such as plasmonic switches, plasmonic modulators, and plasmonic filters, have been developed and implemented. In this thesis, two efficient tunable plasmonic mode converters have been presented to convert transverse magnetic (TM) mode to transverse electromagnetic (TEM) mode in the infrared region. The proposed designs have silver layer with etched holes as metal insulator metal (MIM) waveguides. The holes are filled by nematic liquid crystal (NLC) material to increase the transmission through the suggested structures. Furthermore, the NLC layers have the ability to change modes at the output port. The first design consists of a single output port which converts the TM mode to the TEM mode with high transmission conversion efficiency of 70%. Additionally, the second design allows the generation of the two plasmonic modes instantaneously in two output waveguides. In the biased state of the NLC, the s- mode has transmission conversion efficiency of 50% even though the transmission of a- mode at the unbiased state of the NLC is identical to 49%. It is predictable that the proposed tunable mode converters will performance an important role in the growth of the plasmonic-photonic circuits. The numerical results are obtained using COMSOL Multiphysics software package.