Here we report a novel fabrication approach which enables to integrate 2D nanostructures on the facet of optical fibers by electron beam lithography. The general idea behind this fabrication approach is to planarize the fiber surface in order to fit planar fabrication technology, i.e., that the fibers can be treated in the same way as typical wafers. To demonstrate our approach, we have implemented two types of gold structures on the on the end face of 50 cm long standard single mode fibers (SMF-28): the one is gold nanotrimers lattice and the other is nanodots array. The former is employed as a novel refractive index sensor with a sensitivity of 390 nm/RIU, which represents the state-of-the-art for such a device type. The latter significantly improves the fiber light-collecting ability at an oblique incidence angle with a maximum acceptance angle of 80° breaking the limitation of conventional fiber. This fabrication method is not limited to the nanostructure geometry reported here and can also be applied to dielectric nanostructures, thus opening up the field of fiber optics for planar nanostructures within numerous application fields including bioanalytics, telecommunications, nonlinear photonics, optical trapping and beam shaping.
|