TECHNOLOGIES FOR SILICON DIFFRACTION GRATINGS

Diffraction grating and method for manufacturing it. The diffraction grating has ridges of thickness of at least 1 micron and is made on a silicon substrate. It can further comprise: an anti-reflection coating on the ridges and on the other side of the substrate, an etch-stop layer between the substrate and the ridges. A preferred material is silicon nitrate. Applications for a lidar for an automated vehicle is also disclosed.In some embodiments, grating lines of the diffraction gratings may have several sub-lines that make up each grating line of the diffraction grating. The sub-lines may be sub-wavelength features. In some embodiments, several silicon diffraction gratings may be made from a wafer, such as a wafer with a diameter of 300 millimeters. The wafer may be etched precisely across the entire wafer, leading to a high yield of the diffraction gratings.