Assessing the impact of spatial coherence on the sinusoidal linear Fresnel zone plate’s depth of focus

Abstract

This research examines, using both theory and experimentation, how a light beam’s spatial coherence affects a sinusoidal linear Fresnel zone plate’s depth of focus. We generate a one-dimensional partially coherent Gaussian Schell-model beam from a coherent laser beam through putting a rotating diffuser near to the common focal plane of two cylindrical lenses in a 2f-system. By adjusting the beam spot size on the diffuser, one may modify the coherence width of the produced beam. Our findings demonstrate that when the coherence width of the partly coherent beam drops, the zone plate’s depth of focus increases. Not only is it claimed that the experimental results validate the theoretical conclusions, but a mathematical link is also established between the experimental parameter used to manipulate the light coherence and the theoretically obtained coherence width. This topic has many applications in the field of optical, microscopy, optical trapping, imaging systems and biomedical.