Physics · Wave Optics Young's Double-Slit Experiment Coherent light through two slits paints bright and dark interference fringes.
Physics · Wave Optics Single-Slit Diffraction A single narrow slit spreads light into a broad central band with faint side maxima.
Physics · Wave Optics Circular Aperture — Airy Rings Light through a round hole forms a bright disk ringed by concentric halos.