Focusing of hyperbolic-cosine-Gaussian beam with a spiral phase plate

The focusing properties of the hyperbolic-cosine-Gaussian beam induced by spiral phase plates are investigated numerically. The phase plate may alter the wavefront phase of the hyperbolic-cosine-Gaussian beam by topological charge which results in spiral optical vortex. Results show that the topological charge of the spiral phase plate influences focal intensity distribution considerably, and some novel focal patterns, focal split appear in focal evolution with different topological charge. The focal evolution differs for different parameters in cosh parts of the hyperbolic-cosine-Gaussian beam. The optical gradient force is also illustrated to show promising application of the hyperbolic-cosine-Gaussian beam containing the spiral optical vortex in optical tweezers array.