Patent ID: 7894136

Claim:
A method for creating a periodic interference pattern of coherent waves in two or three dimensions, D, the method comprising: generating at least D+2 waves, wherein each wave has a substantially identical wavelength, λ, and travels substantially in a unique direction, k i , wherein the subscript, “i” is an index variable used to indicate a wave; directing said waves such that at least a portion of each wave intersects in a common excitation region to create the pattern, wherein: the directions, k n , of the waves are selected such that the interference pattern within the excitation region forms a Bravais lattice, wherein the subscript, “n” is an index variable used to indicate a plurality of waves; at least one wave travels substantially in a direction, k i , such that one or more symmetry operations characteristic of the Bravais lattice map the direction of the wave, k i , onto a direction of a different wave, k i , wherein the subscript, “j” is an index variable used to indicate a wave that is different from another wave that is indicated by the subscript “i”; and the directions of the waves, k n , do not all lie on a D-dimensional set of mutually orthogonal axes.