Date of Award
Doctor of Philosophy (PhD)
Electrical and Computer Engineering
Committee Member 1
Committee Member 2
Vladimir M. Shalaev
Light incident on a metallic structure excites collective oscillations of electrons termed as plasmons. These plasmons are useful in control and manipulation of information in nanoscale dimensions and at high operating frequencies. Hence, the field of plasmonics opens up the possibility of developing nanoscale optoelectronic circuitry for computing and sensing applications. One of the challenges in this effort is the lack of tunable plasmonic resonance. Currently, the resonant wavelength of plasmonic structure is fixed by the material and structural parameters. Post-fabrication dynamic control of a plasmonic resonance is rather limited.^ In this thesis we explore the combination of optoelectrical properties of graphene and plasmon resonances in metallic nanostructures to achieve dynamic control of plasmon resonances. First, we show that it is possible to use the highly tunable interband transitions in graphene to effectively control the plasmonic resonance in mid-infrared (MIR) wavelengths. We then outline the current challenges in achieving modulation in the technologically relevant near-infrared (NIR) wavelengths. One potential solution is to combine Fano resonances in metallic structures with graphene to realize a higher degree of tunability at NIR wavelengths. In addition to modulating resonances in metallic nanostructures, graphene itself supports highly confined and tunable plasmons in MIR wavelengths. We report experimental studies on the plasmonic resonance in multilayer graphene, and the interaction of graphene plasmons with the substrate phonons. Finally, we conclude with the current challenges and present directions for further improvements so as to enable practical devices.
Emani, Naresh Kumar, "Dynamic control of plasmonic resonances with graphene based nanostructures" (2014). Open Access Dissertations. 265.