Plug-Play Plasmonic Metafibers for Ultrafast Fiber Lasers

TL;DR

This paper introduces a practical method to fabricate plasmonic metasurfaces on standard fiber tips, enabling ultrafast fiber lasers with tunable properties and paving the way for advanced optical systems.

Contribution

Developed a fabrication process for plasmonic metafibers with plug-and-play interfaces, demonstrating their integration into ultrafast fiber lasers with sub-picosecond pulses.

Findings

Achieved sub-513 fs soliton mode locking at 1.5 and 2 micrometers.

Demonstrated tunable plasmonic resonances and nonlinear optical responses.

Provided insights into the saturable absorption mechanisms of plasmonic metasurfaces.

Abstract

Metafibers expand the functionalities of conventional optical fibers to unprecedented nanoscale light manipulations by integrating metasurfaces on the fiber tips, becoming an emerging light-coupling platform for both nanoscience and fiber optics communities. Mostly exploring the isolated bare fibers, current metafibers remain as proof-of-concept demonstrations due to a lack of standard interfaces with the universal fiber networks. Here, we develop new methodologies to fabricate well-defined plasmonic metasurfaces directly on the end facets of commercial single mode fiber jumpers using standard planar technologies and provide a first demonstration of their practical applications in the nonlinear optics regime. Featuring plug-play connections with fiber circuitry and arbitrary metasurfaces landscapes, the metafibers with tunable plasmonic resonances are implemented into fiber laser cavities, yielding all-fiber sub-picosecond (minimum 513 fs) soliton mode locked lasers at optical wavelengths of 1.5 micrometer and 2 micrometer, demonstrating their unusual polarimetric nonlinear transfer functions and superior saturation absorption responses. Novel insights into the physical mechanisms behind the saturable absorption of plasmonic metasurfaces are provided. The nanofabrication process flow is compatible with existing cleanroom technologies, offering metafibers an avenue to be a regular member of functionalized fiber components. The work paves the way towards next generation of ultrafast fiber lasers, optical frequency combs, optical neural networks and ultracompact "all-in-fibers" optical systems for sensing, imaging, communications, and many others.