Generation of propagation invariant vector flat-top beams

Laser beams structured to have a uniform peak intensity profile (flat-top) have become ubiquitous and a topic of research interest in many fields. These beams can be digitally generated using spatial light modulators (SLMs) where an input Gaussian beam is transformed into a flat-top at the focal plane of a focusing lens. However, the resulting uniform peak intensity distribution degrades while the beam propagates in space. Here, we present theoretical simulations and demonstrate experimentally the creation of propagation invariant vector flat-top beams. We achieve this by coaxial superposition of a Gaussian and a donut beam with orthogonal polarization states. The polarization state of the generated vector flat-top beam is characterized using spatially resolved stokes measurements and compared to theoretical simulations. Such beams will be of great impact in the fields of material processing and optical trapping.