Controlling spatial coherence using superposition of Laguerre-Gaussian beams

Abstract

In this study, we constructed a partially spatially coherent beam from a spatially coherent light source by superposing Laguerre-Gaussian (LG) beams with different topological charges. We used a hologram that is a combination of a circular mask and superposed LG beams, where each beam has a different topological charge and is masked with a random matrix of 0's and 1's. We simulated a double slit by masking the hologram, then measured the intensity contrast of the interference pattern formed. We observed that increasing the slit separation decreases the fringe intensity contrast, indicating that the beam is partially spatially coherent. We also observed that increasing the number of superposed LG beams further decreases the beam's degree of coherence. This study shows promising potential for developing precision control of spatial coherence through the superposition of LG beams with different topological charges.