Resonant Light-Matter Interaction for Enhanced Control of Exotic Propagation of Light

Abstract

We investigate the propagation of light in different conditions that lead to exotic propagation of photons and use near-resonant light-matter interactions to enhance these effects. First, we study the propagation of light in a moving highly dispersive medium, namely rubidium atoms. Based on the special relativity the speed of light changes with the speed of the medium. However, this drag effect in a non-dispersive medium is very small and thus difficult to measure. We show that the drag effect is enhanced significantly when the moving medium is highly dispersive. Thus, with this enhancement even a slow motion can be detected. Next, we employ the large nonlinear response of rubidium atoms to accentuate the formation of optical caustics. Caustics are important as nature uses caustics to concentrate the energy of waves. Moreover, caustics can be formed in many physical systems such as water waves in oceans to amplify tsunamis or generate rogue waves. The connection of our study to these giant water waves is discussed. Finally, we explore light-matter interactions in plasmonic systems. We show that photons experience a significant phase jump as they couple into and out of a plasmonic structure. This coupling phase, also known as the scattering phase shift, is generic to all scattering events. We measure this coupling phase with a triple-slit plasmonic structure. Moreover, we use the near-field enhancement of the plasmonic structure to enhance the coupling between the slits. Consequently, the photons can take non-trivial trajectories that pass through all three slits. We measure such exotic trajectories for the first time that are seemingly in violation of the superposition principle. The application of the superposition principle and the validity of Born’s rule is discussed.