| Surface plasmons (SPs), which generate strong localized electromagnetic fields at metal surface, have been capturing worldwide attention recently because they establish an important link between light and matter. Due to their ability to route and manipulate photon at the nanoscale, SPs have been widely used in nano- and bio-photonics including biosensor, surface enhanced Raman scattering, optical tweezers, light emitting diodes, solar cell, and metamaterials, etc. However, although it is known that system geometry, material, wavelength, excitation condition are important in governing the behaviors of SPs as well as matter/SPPs interactions, how they work together in producing the final outcome is largely unknown. More importantly, there seems to be a "missing link" between these extrinsic parameters and the properties of SPs such that, for example, it is still not quite understood the exact roles of geometry play in controlling the SPs and their related properties.;In this thesis, we aim at bridging the link between extrinsic parameters and SPs properties based on temporal coupled-mode theory (CMT). CMT provides the knowledge of intrinsic parameters such as SPs radiative and absorption rates and their relationships with the phase, amplitude, and directionality of SPs. Because decay rates are strong function of system parameters, excitation condition, etc, connection between the extrinsic parameters and the SPs properties can now be established. With the decay rates and other accessories in hand, we study the fundamental of SPs from another perspective. For example, we examine how two degenerate SPs modes couple to yield a pair of dark and bright modes and find not only the radiation damping of SPs but also the absorption are modified. In addition, we study the decay length and the group velocity of SPs in real- and momentum- space to elucidate the interplay between the SPs losses and the wavevector-resolved projected density-of-optical-states (PDOS). We also explore the rate matching (i.e. critical coupling) for optimizing the phase-jump in SPs resonance sensing and achieve high figure of merit in sensing performance. Finally, the coupling between SPs and light emitters has been studied and it is found that their coupling rate is governed by PDOS. |
