An optical lattice is formed by the intersection of multiple laser beams, producing a standing wave pattern. Within that pattern, as the beams interact with each other, there are regions with higher and lower light intensity. An atom placed in the lattice will naturally tend to seek the minimal or maximal intensity points depending on the laser frequency with respect to the atom's internal state. Because lattice configurations resemble the geometrical arrangements of atoms in crystalline solids, they can be used to study atomic behaviors in a highly controlled environment. The spacing of atoms in this artificial crystal is determined by the wavelength of light and the angles at which the laser beams overlap--half a micron is typical.