How DIY Photon Sieves Shape Laser Wavefronts

HN points to it for a clear explanation of photon sieves versus Fresnel lenses and for showing what interference patterns actually look like.

Huygens Optics shows how DIY photon sieves shape a laser's wave front, explaining how they differ from zone plates and how aperture count affects the focal point, with time-resolved visualizations of the diffraction.