Abstract
We have focused our discussion on the case of a periodic dipole potential created by a standing wave of sinusoidally varying intensity in space. We have applied to this problem the tools originally developed in solid-state physics to deal with electron motion in the periodic potential of a crystal lattice. We have shown that the natural energy scale is given by the "recoil energy", i.e. the kinetic energy acquired by an atom initially at rest when it absorbs a photon. We have presented Bloch's theorem, the notion of the Brillouin zone and described the limit of weak bonds where the light potential is small compared with the recoil energy. This limit is used in particular in the many Bragg diffraction experiments.
