تصميم هوائي ضوئي يعمل ضمن نطاق تحت الحمراء الترددي باستخدام تقنية البلازمونك == Optical Antenna Design In Ir Range Using Plasmonic Technology
Author name:
هادي كريم شمخي
Supervisor name:
محمد ناظم عباس
General topic:
Electrical, Electronic and Communications Engineering
Specific topic:
Electrical Engineering
Degree:
Master
University:
University of Baghdad - College Of Engineering - Department Of Electrical Engineering
Language:
English
University location:
Baghdad
First pages:
34T498 - p.pdf
Abstract:
Optical antennas, resonant structures, which efficiently collect free - space light and focus it into a nanoscale volume using plasmonic, are indispensable in the burgeoning field of nanophotonics. In this work, resonance behaviors of the fundamental resonance mode of diabolo gold metal bar optical antennas were investigated. The relationship between the near - field enhancement, absorption, and scattering spectra of localized plasmonic elements was explored. It was found that as the waist of the diabolo gold metal bar optical antenna was reduced, optical energy absorption cross section and near field enhancement at resonance increased significantly. Also reduction of the diabolo waist width caused redshift of the resonant wavelengths in the spectra of absorption cross - section, scattering cross - section, and the near electric field. Oppositely, it was found that as the length of the diabolo gold metal bar optical antenna was reduced, optical energy absorption cross section and near field enhancement at resonance decreases significantly. Also reduction of the diabolo length caused blue - shift of the resonant wavelengths in the spectra of absorption cross - section, scattering cross - section, and the near electric field.Grating surface diabolo antenna design was proposed. It was found that grating superstructure perturbed the optical properties of SPPs (Surface Plasmon polarions) and enabled the control of resonance wavelength of the antenna. The grating reduced the power that flow out from the antenna and enhanced the localized electromagnetic fields intensity. The grating also increased surface plasmon currents because of the formation of bound surface states. As a result, the absorption spectra and near field intensity were enhanced but at the same time, the scattering spectra and the far field pattern were reduced.Titanium - Gold grating surface diabolo antenna was proposed. It was found that titanium metal strengthen the grating perturbation of the optical properties of SPPs and allowed wide range of wavelength shifting (3.5 ?m). Because Gold and Titanium have difference electrical resonance characteristics, less plasmon damping occurred, resulting in lower scattering efficiency and narrower plasmon line widths.Finally, system modelling and simulations is done by using electrical department super computer (24 parallel MP and 64 GB RAM) and COMSOL multiphysics 4.4 software.
