Patent ID: 7826066

Claim:
A grating system for analyzing the wavefront of a light beam, comprising: (a) a two-dimensional intensity grating with hexagonal elementary meshes each having a surface where there is arranged an elementary intensity pattern with said elementary intensity mesh surface; and (b) a two-dimensional phase grating with hexagonal elementary meshes each having a surface equal to three times said elementary intensity mesh surface, where there is arranged an elementary phase pattern having a surface equal to three times said elementary intensity mesh surface; (c) all six apexes of an elementary phase mesh matching with the apexes located at one of the ends of the six small diagonals of three adjacent elementary intensity meshes, the other end of said small diagonals being located at the common apex of said three adjacent elementary intensity meshes; (d) said elementary intensity pattern being such that it introduces a variation of intensity from a secondary beam crossing said elementary intensity pattern between a maximum value of 100% at the center of said elementary intensity pattern, and a minimum value of 0% on the apexes of said elementary intensity pattern; (e) said elementary phase pattern being such that it introduces a phase shift close to 2π/3 (modulo 2π) between two secondary beams crossing two adjacent elementary intensity patterns.