Boosting Light Collection Efficiency of Optical Fibers Using Metallic Nanostructures

Optical fibers represent one of the most important photonic components with applications in numerous fields; however, their performance with respect to light collection at large incident angles is severely limited. Here, we show that arrays of metallic nanodots located on the end faces of regular step index fibers allow addressing incoupling angles up to 80° at high efficiencies, representing a regime in which bare fibers fail to operate. The experimental demonstrations including lithographic implementation and optical characterization supported by corresponding numerical simulations and a toy model reveal the feasibility and potential of the concept of nanostructure-enhanced fiber incoupling, which is compatible with other types of nanostructures and can lead to significant improvements, particularly in the fields of bioanalytics and quantum technologies.