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 μ m range through control of the tapering speed and temperature. Extending this approach to the fabrication of polymer and glass nanoparticles appears feasible.