Phys.org  November 6, 2023 Existing terahertz inspection systems face throughput and accuracy restrictions due to their limited imaging speed and resolution. Furthermore, machine-vision-based systems using large-pixel-count imaging encounter bottlenecks due to their data storage, transmission, and processing requirements. Researchers at UCLA developed a diffractive sensor that rapidly detects hidden defects/objects within a 3D sample using a single-pixel terahertz detector, eliminating sample scanning or image formation/processing. Using deep-learning-optimized diffractive layers, the diffractive sensor could all-optically probe the 3D structural information of samples by outputting a spectrum, and directly indicated the presence/absence of hidden structures or defects. They experimentally validated this framework […]