Optical antennas have become ubiquitous tools to enhance the spontaneous emission of atoms, molecules and quantum dots. In this presentation, we report a series of experimental results investigating the emission of light by ensembles of interacting emitters coupled to resonators. First, we report the observation of a strong plasmon−exciton coupling regime in a system consisting of a layer of nanoplatelets on top of a gold planar surface. Reflectometry measurements and mode analysis lead to the non-ambiguous derivation of a Rabi splitting between two polaritonic branches. Secondly, we investigate the polarized and directional emission of light by a patterned layer of nanoplatelets optically pumped. Models based on the paradigm of the Purcell effect mediated radiation fail to fully explain spectral and spatial features observed in such experiments, such as the emergence of spatial coherence or the suppression of quenching. We discuss and highlight the differences between emission by a single emitter and by a thermalized assembly of quantum emitters to show that a statistical framework is required to understand their interactions with optical antennas. Based on these considerations, we introduce a model of light emission by thermalized ensembles of emitters, and find good agreement between our model and experimental data.
In this paper, we discuss recent progress obtained on infrared nanocrystal based on mercury chalcogenides (HgTe and HgSe). These materials can become some key building blocks for the next generation of infrared optoelectronic devices. To reach this goal, the infrared nanocrystals need to combine fine control on the optical features and efficient electronic transport. Here, we report about (i) the development of HgTe NPL for enhanced optical features (narrower and faster PL) in the near IR and (ii) about the development of self-doped nanocrystals of HgSe to demonstrate tunable intraband absorption up to the THz range.