Near-field study of surface plasmonic lenses for nanofocusing applications

Optical imaging has been utilised as a unique method for investigating specific properties of materials. However, the optical resolution is limited by the Rayleigh diffraction limit. This thesis has used the unique properties of surface plasmons lending them to the design of a circularly symmetric three dimensional nanoscopic structure. This structure can focus the energy of a plasmon to a very small volume, much beyond the diffraction limit. In this thesis, the author presents a circular ring plasmonic lens which can focus two wavelengths of light to the same focal plane, opening up applications in super-resolution imaging and optical-data storage.