Spatial Consequences of Electromagnetically Induced Transparency: Observation of Electromagnetically Induced Focusing

Within an experiment to produce electromagnetically induced transparency the radial intensity profile of the strong coupling laser can generate a significant spatial refractive index profile which is experienced by the weak probe laser as it tunes through the transparency window. This can lead to focusing and defocusing at separate, but close, probe laser detunings. This behavior is observed using continuous-wave lasers in rubidium vapor, in agreement with our predictions.