Thermally expanded core fiber: a novel platform for meta-fibers

Meta-Fibers, which incorporate 3D-printed Metalens into optical fiber facets, are versatile technology with applications in imaging, optical trapping, and electromagnetic wave manipulation. Single-Mode Fiber (SMF) stands out for its defined output, but its limited mode field diameter poses a challenge, often requiring fusion splicing with Multi-Mode Fiber (MMF) or a 3D-printed structure to expand SMF's usable cross-section. However, these methods are complex and may damage the Meta-Fiber. This study introduces an alternative, replacing SMF with Thermally Expanded Core (TEC) fiber, featuring a significantly larger mode field diameter. This approach enables optical trapping and imaging via 3D laser-printed ultra-high numerical aperture metalens into TEC fibers, functioning effectively in diverse environments. The findings expand Meta-Fiber applications, providing an efficient, robust, and scalable solution for optical wavefront manipulation, highlighting the potential of TEC fibers in optics and photonics technology.