Fiber tip integrated metalens for polarization-dependent dual-focus.

Metalenses tremendously manipulate the incident light to focus beam by carefully selecting and arranging the meta-atoms. However, their integration with optical components is a challenge. Existing approaches often involve bulky intermediary optics or limited alignment precision, restricting their practical applications in fiber-based systems. In this study, we propose and implement a method for integrating a dual-channel metalens with a spun fiber, enabling focusing at 210 µm and 130 µm under two circularly polarized channels with opposite handedness. This method utilizes an align-bond-peel process to rapidly and conveniently integrate metalens on the fiber tip while ensuring excellent performance. It holds immense potential for many applications such as polarization-multiplexed optical communication, fiber-integrated sensing, and advanced photonic systems, where compact, efficient, and multifunctional optical devices are increasingly in demand.