Effect on the Coupling between Patterned Disordered Emitters and Surface Plasmons

Abstract

In this paper, we present our recent research on light-matter coupling between plasmons and molecular emitters. Depending on the light-matter interaction strength, these hybrid systems can exhibit different behavior: weak or strong coupling [1], [2]. In the weak coupling regime, each parts of the system keeps its optical properties: no hybridization occurs between light and matter. In the strong coupling regime, plasmon/emitter interaction overtakes the damping in the system leading to an emerging new light-matter mixed state: the polaritons. This new state is then delocalized over numerous emitters on a wide distance, typically several microns [3], leading to a coherent state, allowing the modification of the material properties.We investigate, in these researches, the consequences on the optical properties of the structuration in plasmon/organic emitters systems. The structuration consists in lines of J-aggregated dye on silver. The optical properties of such systems are studied as a function of several parameters such as the geometry of the pattern or the orientation of the propagation direction, i.e. parallel or orthonormal to the array of lines.Depending on the pattern size, one can observe only one electromagnetic mode corresponding to the polariton, or the superposition of several modes: plasmon and polaritons. The first situation corresponds to an area where only strong coupling occurs, as the second situation reveals that the system exhibits strong and weak coupling at the same time. These results strongly suggest that in our system, the length of interest that should be taken into account for the physical properties, is not related to the wavelength as can be expected, but seems to arise from the plasmon/polariton propagation length. This behaviour reveals the potential of our sample as metasurfaces.