Optical fiber meta-tips: Perspectives in sensing applications

In this work we review the concept of optical fiber meta-tips, recently introduced by the authors. Optical fiber meta-tips come from the integration of plasmonic optical metasurfaces and the fiber optics technology. In particular, this integration is a major breakthrough in the recently emerged "Lab-On-Fiber" technology, where nanostructured platforms with special capabilities of light manipulation are integrated onto the tip of an optical fiber. Optical fiber meta-tips can, on one side, boost the real world applicability of optical metasurfaces, and, on the other side, bring about more advanced capabilities of on-fiber control and manipulation of light wavefront and polarization. With a view towards possible practical applications to label-free chemical and biological sensing, we inspect the potentialities of optical fiber meta-tips to work as sensors of local refractive index variations, and aim at studying the effect that the phase gradient impressed by the metasurface has on the surface sensitivity of proposed devices.