In this dissertation, the main focus has been on the manipulation of optical absorption. That is to either decrease the unwanted losses or increase the desired absorption for specific applications. The approaches have been chosen to provide insightful design of metamaterial structures at optical and near infrared wavelengths. Modeling using equivalent electric circuit theory and numerical simulation using fullwave and scattered wave finite element method are the tools of calculations. The main focus of low the loss part has been on highly interesting materials in the near infrared such as plasmonic particles of aluminum doped zinc oxide. Solar cells and plasmonic photovoltaics have also been the driving interest to design and optimize the structures for higher efficiency in the next generation of devices.Successful results have been achieved in the course of this research into plasmonics nanoparticles and also composite nanoantenna-nanowire elements. The results are presented in two different chapters and their sections within. The sections are written to be standalone and provide the reader the flexibility to easily navigate through the basics, methods and results. A list of related publications is available at the end of this document.
