All-fiber focused beam generator integrated on an optical fiber tip

Abstract

We report a compact all-fiber focused vortex beam generator, where a spiral zone plate (SZP) is integrated on the tip of a composite optical fiber microstructure with the femtosecond laser two-photon polymerization. The experimental characteristics of the beam produced from the focused vortex beam generators, such as the focal length, focal spot diameter, and vortex topological charge, are in excellent agreement with the results from finite-difference time-domain simulations. Adjusting the design parameters of the SZP integrated on the fiber tip, we can realize the precise manipulation of the generator’s output light field. Since the intrinsic high divergence of a vortex beam during propagation is effectively overcome, the generators may have potential applications for optical fiber optical wrench, all-fiber stimulated emission depletion microscopy, or orbital angular momentum fiber communication. Moreover, the compact generators also have a good anti-interference ability and long-term stability.