High-quality and controllable hollow beam generation by a liquid-core optical fiber

Abstract

We present the generation of high-quality and beam parameter controllable hollow beams with a liquid-core optical fiber (LCOF) filled with CS2 by adjusting off-axis orientation and LCOF structure. The dependences of the dark spot size (DSS), ring beam width (RBW) and transverse field intensity distribution of the hollow beam on the incidence angle of laser beam, the length and core diameter of the LCOF are investigated experimentally, and analyzed theoretically by using Zemax simulation. The results show that the quality of the hollow beam is related to the times of total internal reflection of skew rays in the fiber core; the DSS and RBW are closely controlled by the incidence angle and core diameter. High-quality thin-ring hollow beam is achieved experimentally by the LCOF of the core diameter of 100μm and the length of 1m with the incidence angle of less than 10°. The hollow beam generated has high stability, and is weakly dependent on the bending of the LCOF.