Coherent Plasmon-Plasmon and Plasmon-Exciton Interactions at the Nanoscale

Licentiate thesis, 2015

Noble metallic nanoparticles which supports localized surface plasmon resonances, offers a variety of potential scientific as well as industrial applications. Due to a remarkable ability to confine light at nanoscale dimensions, far below the optical diffraction limit, together with an ability to detect minute changes in the local environment plasmonic nanoparticles have paved routes towards several new and intriguing techniques, promising for future applications in areas such as molecular sensing and quantum optics. The exploitation of coherent interations at the nanoscale is rather frequent in the scientific community, and has recently resulted in several prominent discoveries, which have ended up as publications in high-ranked scientific journals. However, numerous studies demonstrates utilization of coherent interactions in rather complicated systems, which is often costly and impractical for future development. Plenty of the phenomena presented within these studies are moreover based on measurements on an ensemble level, where there is either no or very limited knowledge in the performance of single nanoparticles. In this thesis we first present and demonstrate ways to acheive ultracompact and competitive molecular analysis in nanosized systems, which supports directional scattering properties due to coherent plasmon-plasmon interactions. Secondly we also demonstrates realization of strong light-matter interactions from plasmon-exciton coupling in nanosized systems comprised by single crystalline Ag nanoprisms and J-aggregated molecular sheets of TDBC. These demonstrations support promising outlooks for future plasmonic molecular analysis as well as room temperature quantum plasmonics and quantum optics.