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Free keywords:
ARROW WAVE-GUIDES; OPTICAL-FIBER; REFRACTIVE-INDEX; LIQUID CORES; LASER;
SPECTROSCOPY; PARTICLES; SENSORScience & Technology - Other Topics; Materials Science; Optics; Physics; optomechanics; nanophotonics; optofluidics; hollow-core photonic crystal
fiber; waveguides;
Abstract:
We report a novel technique for launching broadband laser light into liquid-filled hollow-core photonic crystal fiber (HC-PCF). It uniquely offers self alignment and self-stabilization via optomechanical trapping of a,fused silica nanospike, fabricated by thermally tapering and chemically etching a single mode fiber into a tip diameter of 350 nm. We show that a trapping laser, deliirering similar to 300 mW at 1064 nm, can be used to optically align and stably maintain the iianospike at the core center. Once this is done, a weak broadband supercontinuum signal (similar to 575-1064 nm) can be efficiently and close to achromatically launched in the HC-PCF. The system is robust against liquid-flow in either direction inside the HC-PCF, and the Fresnel back-reflections are reduced to negligible levels compared to free-space launching or butt-coupling. The results are of potential relevance for any application where the efficient delivery of broadband light into liquid-core waveguides is desired.
