1- and 2-dimensional plasmonic nanostructures : design, fabrication and characterization

Surface plasmon polariton (SPP) has captured huge interest because of the ability to work in optical range as well as interaction with nanostructures. Its potential applications include waveguides, plasmonic-electronic chips and sensors. The ability to sense minute changes in effective refractive index remains the most prominent and is thus the focus of this thesis. SPP excitation can be done through prism coupling or a periodic structure (plasmonic crystal). Plasmonic crystals (PCL) are preferred since they provide more flexibility to control SPP propagation and possess richer structures. This thesis explores the behaviour of 1D and 2D PCL by refractive index engineering, followed by optical characterization to study SPP response due to azimuthal rotation, where double SPPs and other crystal momentum can be excited with optimized polarization thus change its propagation direction. These approaches are done to obtain electromagnetic field enhancement for sensing purposes. One way to accomplish refractive index engineering is physically through the dimensional orders of PCL. The plasmonic response of 1D, 1D to 2D transitional and 2D PCLs are studied experimentally and reported. In 2D PCL, the presence of diagonal crystal momentum will benefit due to the ability to explore first and second Brillouin zones. It will act as a complementary vector probe to explore conditions which are otherwise impossible to be done by the main axis due to limitations in wavelength and incident angle. Besides physical means, controlling SPP can be accomplished by engineering dielectric medium. The extraordinary transmission and plasmonic crystal ellipsometry will serve as complements to the 2D SPR technique. The combination of these approaches will be able to replace the prism and 1D PCL coupled SPR based sensor with better sensitivity and eliminate the surface chemisorptions requirement.DOCTOR OF PHILOSOPHY (MSE