Hyperbolic-cosine-Gaussian beam focusing with a non-spiral vortex and a spiral vortex

摘要

Singular optics studying optical vortices, or phase singularities, has grown rapidly recently because optical vortices have some interesting properties and promising applications, for instance, to construct highly versatile optical tweezers. In this article, the focusing properties of hyperbolic-cosine-Gaussian beam, which contains a non-spiral optical vortex and a spiral optical vortex, are investigated numerically. The phase plate may be used to construct non-spiral optical vortex by putting phase plate in a half section part of hyperbolic-cosine-Gaussian beam. Results show that the parameters of non-spiral optical vortex and spiral optical vortex influence focal intensity distribution considerably, and some novel focal patterns, such as line focal spot, "H" shape focal spot, and intensity peaks array, may occur. Focal shift and focal split may also appear in focal evolution with tunable parameters of vortices terms. The focal evolution differs for different parameters in cosh parts of hyperbolic-cosine-Gaussian beam.