Examples include a method for fabricating a grating mirror using a computing device that comprises calculating a target phase change across the grating mirror. The target phase change may correspond to a target wavefront shape in a beam of light reflected from a grating patter. The method may also comprise generating the grating pattern comprising a plurality of lines with line widths, line period spacings, and line thicknesses corresponding to the target phase change across the grating mirror using the computing device. In such examples, a set of coordinates may be generated using the computing device with each coordinate identifying a location of a line of the plurality of lines, a line width of the line, a line period spacing of the line, and a line thickness of the line.