Competence Center for Micro- and Nanotechnologies

Optical fibers represent one of the most important photonic components with applications in numerous fields while their performance with respect to light collection at large incident angle is strongly limited. Here we show that arrays of metallic nano-dots located on the end faces of regular step index fibers allows addressing incoupling angles up to 80° at high efficiencies, representing a regime bare fibers completely fail to operate. The experimental demonstration including lithographic implementation and optical characterization supported by corresponding numerical simulations and a toy model clearly reveal the feasibility and potential of the concept of nano-structure enhanced fiber incoupling, which is compatible with other types of nano-structures and can lead to great improvements particular within the fields of bioanalytics and quantum technologies.