Patterned loading
By imposing a "superlattice" on top of the normal optical lattice it is possible to perform patterned loading of the lattice. In (a) only every third lattice site contains atoms, whereas in (b) every site is occupied. This can be seen by comparing the matter-wave interference patterns of the two configurations: the large separation between atoms in (a) results in the interference pattern having a smaller period. If, on the other hand, the spacing between the matter waves is smaller, as it is in (b), the period of the interference pattern increases. This is analogous to coherent light diffracting from a grating with a larger and smaller grating period. Credit: W Phillips and T Porto/NIST Gaithersburg.