Strong Light-Matter Interactions in Cubic Nanostructures Hybridized with Cyanine J-aggregates

Abstract

Strong coupling between light and matter can lead to the formation of hybrid eigenstates, such as exciton-polaritons, enriching our understanding and manipulation of quantum phenomena across various fields of science and technology. Although plasmonic metal nanoparticles serve as effective optical resonators for generating polaritons, most research thus far has concentrated on Au nanorods. The potential of cubic nanoparticles and the strategy of layering emitters on particle surfaces have not been extensively explored in this field. This thesis presents discoveries regarding the strong coupling observed between cubic nanoparticles and molecular J-aggregates. Our findings indicate that the coupling strength can be adjusted by manipulating the geometric and material properties of the cubic nanoparticles, as demonstrated by spectral splitting, anti-crossing in dispersion relations, and the fulfillment of strong coupling criteria. To further amplify plasmon-exciton coupling, we introduced a layer-by-layer modification approach and observed a maximal enhancement of approximately 19% for double layers of J-aggregates. Simulations on the interlayer thickness-dependent splitting enhancement support these findings, offering deeper insight into the effects of emitter layering on plasmon-exciton strong coupling.