In physics, Bragg's law, Wulff–Bragg's condition or Laue-Bragg interference, a special case of Laue diffraction, gives the angles for coherent scattering of waves from a crystal lattice. It encompasses the superposition of wave fronts scattered by lattice planes, leading to a strict relation between wavelength and scattering angle, or else to the wavevector transfer with respect to the crystal lattice. Such law had initially been formulated for X-rays upon crystals but is moreover relevant for all kind of quantum beams, such as neutron and electron waves on atomic spacing, as well as for visual light on artificial periodic micro-scale lattices.