Sub-millimeter helical fiber created by Bessel vortex beam illumination

We demonstrate a self-written sub-millimeter (>300 μm) helical fiber in a photo-cure resin by irradiation of non-diffractive 1 st -order Bessel beam with an orbital angular momentum. The twisted direction of the helical fiber can be controlled by only reversing the sign of the topological charge of Bessel beam.