For the first time, researchers have used a surface normal nonlinear photodetector (SNPD) to improve the speed and energy efficiency of a diffractive optical neural network (ONN). The new device lays the groundwork for large-scale ONNs, which can perform high-speed processing at the speed of light in an extremely energy efficient manner.For the first time, researchers have used a surface normal nonlinear photodetector (SNPD) to improve the speed and energy efficiency of a diffractive optical neural network (ONN). The new device lays the groundwork for large-scale ONNs, which can perform high-speed processing at the speed of light in an extremely energy efficient manner.Hi Tech & Innovation[#item_full_content]