Designing surfaces that precisely control how light behaves at the nanoscale is tricky. Optical Fourier surfaces, which are nanostructured gratings that redistribute light into specific directions and wavelengths, hold enormous potential for compact spectrometers, augmented-reality displays, and adv anced sensors. However, their standard design process relies on computer simulations that assume idealized conditions such as single-angle illumination and the absence of fabrication imperfections—a far cry from reality. ...read more read less