Fiber-interfaced hollow-core light cage: a platform for on-fiber-integrated waveguides

Here, we demonstrate the realization of hollow-core light cages (LCs) on commercial step-index fibers using 3D nanoprinting, resulting in fully fiber-integrated devices. Two different light cage geometries with record-high aspect ratio strands and unique sidewise access to the core have been implemented, exhibiting excellent optical and mechanical properties. These achievements are based on the use of 3D nanoprinting to fabricate light cages and stabilize them with customized support elements. Overall, this approach results in novel, to the best of our knowledge, fiber-interfaced hollow-core devices that combine several advantages in a lab-on-a-fiber platform that is particularly useful for diffusion-related applications in environmental sciences, nanosciences, and quantum technologies.