Fabrication of Nanoplasmonic Structures to Explore Fano Resonance Tunability

Misra, Subhradeep (2015) Fabrication of Nanoplasmonic Structures to Explore Fano Resonance Tunability. Masters thesis, Indian Institute of Science Education and Research Kolkata.

PDF (MS dissertation of Subhradeep Misra) Subhradeep_Misra-10MS34.pdf - Submitted Version Restricted to Repository staff only Download (2MB)

Abstract

Since its invention, the asymmetric profile of Fano resonance has been a characteristic feature of interacting quantum systems. The shape is distinctively different from other conventional symmetric resonance curves and the phenomenon has been discovered in plasmonic nanoparticles, photonic crystals and electromagnetic metamaterials. Here our main work is to fabricate nanostructures using electron beam lithography and thin film deposition technique. Subsequently, using a dark field microscope, the spectra resulting from the scattering of light due to nanostructures are recorded to exhibit the Fano resonance characteristics. The Mueller matrix of the plasmonic systems is also obtained from measurements, and therefore different polarization states are used to tune and enhance the Fano-type characteristics therefore the dependence of this characteristic line shapes on input and output polarization states of light are studied. Finally, the tunability of this asymmetric resonance profile is explored by the variation of shape and size of the nanostructures. This tunability promises applications in chemical and photonic sensing, lasing, switching and slow-light devices. Also, some interesting future work directions, mainly study of spin-orbit interactions due to scattering from nanoplasmonic structures are discussed.

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