Equal-intensity beam splitter fabricated by tandem dielectric beam splitters for passive laser speckle reduction

An equal-intensity beam splitter that utilizes tandem dielectric beam splitters with specific splitting ratios and a high-reflectivity mirror for passive laser speckle reduction is presented. The beam splitter coatings of the dielectric beam splitters were designed using Essential Macleod software simulations; specifically, three laser sub-beams of equal optical intensities were generated. The optical path delay between laser sub-beams destroyed the temporal and spatial coherence of the laser. The objective speckle contrasts decreased from 0.75 to 0.47 when all three laser sub-beams were utilized. The study demonstrates the potential of the equal-intensity beam splitter, which can be designed to be compact and static, for laser projection.