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Observation of the Plateau-Rayleigh capillary instability in multi-material optical fibers

We report the observation of the Plateau-Rayleigh capillary instability during the tapering of a multi-material optical fiber. The fiber core is a glass, and the cladding is an amorphous polymer. The instability is manifested in the breakup of the core into a periodic string of size-tunable micro-scale droplets embedded along the fiber axis. The particle diameters may be tuned in the 1–20 μm range through control of the tapering speed and temperature. Extending this approach to the fabrication of polymer and glass nanoparticles appears feasible.