Critical Issues in Localized Plasnnon Sensing

Localized surface plasmons (SPs), that is, charge density oscillations in metallic nanostructures often excited by coupling to electromagnetic radiation, have been widely studied for use in sensing applications. Here we present recent work from our group related to several major issues in the field, which have not been treated in depth in previous reviews. Specifically, we discuss the distance dependence of the localized plasmon response; the differences in response between transmission and reflection mode measurements; comparison with other, closely related sensing techniques; the use of sandwich configurations (e.g., biological sandwich assays) to enhance the response; and the search for alternative plasmonic materials, other than the widely used (but expensive) gold and silver. For each topic we review the existing literature and provide a detailed account of our contributions.