Phys.org  November 18, 2024 Researchers at Stevens Institute explored a novel approach to surface roughness metrology utilizing a single pixel, raster scanning single photon counting LiDAR system. It used a collimated laser beam in picosecond pulses to probe a surface, capturing the changes of back-scattered photons from different points on the surface into a single mode fiber, and counted them using a single photon detector. The back-scattered photons carried speckle noise produced by the rough surface, and the variation in photon counts over different illumination points across the surface becoming a good measure of its roughness. By analyzing the variation […]