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 frequency as the LiDAR scans over the surface using machine learning techniques, they demonstrated general measurements of surface roughness from 1.21 (1.27±4.51) to 102.01 (87.97±10.55) microns… read more. TECHNICAL ARTICLEÂ