A new superresolving design for laser beam shaping

Abstract

In many applications, one repeatedly encounters the problem of laser beam shaping. Shaping laser beam means converting an incident wave front into a desired wave front in the output plane. Superresolution technology can be used for achieving smaller spot than an Airy spot which is the limit of resolution of optical system caused by diffraction. In this work, superresolution technology is extended for laser beam shaping. The aim of the research is to design a new phase-only superresolving element by using local direct search optimization algorithm. The results show that better superresolving performances of our phase elements are obtained compared with those of phase plates of references. The phase element we design is a new type varying in discretely continuous way and is regarded as a hybrid combination of continuous and discrete phase type, whose phase distribution is composed of two parts: the first part is a continuous phase profile; the second part is a constant phase step. The phase steps of this phase plate are different in the different zones. More importantly, it is possible that desired flat-top wave front is obtained by using this design. Therefore, this design provides a novel tool for laser beam shaping.