Fabrication of a pencil-shaped fiber probe for near-field optics by selective chemical etching

We propose a novel method by chemical etching using hydrofluoric (HF) acid and a buffered HF solution (BHF) to fabricate a pencil-shaped fiber probe for near-field optics, We succeeded in producing such probes with high reproducibility using a dispersion-compensating fiber having the high GeO2 doped core, The method involves tapering of the cladding, then sharpening of the core, The fabricated probe has a conical tip with a cone angle of 20 degrees and an apex diameter of less than 10 nm.