Calculation of diffraction efficiency for a planar grating using rigorous coupled-wave theory

The basic concept and formulae of the rigorous coupled-wave theory were give. The diffraction of planar dielectric phase style harmonic grating was discussed when electromagnetic wave of planar polarization was incident upon. The method of using the theory to compute the diffraction efficiency of a planar grating was described, and the procedure of programming was discussed also. A numerical example shows that the computed results of energy distribution of all diffraction orders satisfy the law of energy conservation.