Study of Dark-Hollow Beams Generated with Different Multimode Fibres

A dark-hollow beam (DHB) is generated by a coupling of a single fundamental mode He--Ne laser beam with a misalignment multimode fibre (MMF) in a special way. Effects of the misalignment angle, diameter and length of the MMF are studied. The generated DHBs can be used for guiding and trapping of atoms, manipulating particles, or as optical tweezers.