| 摘要 |
The invention relates to a diffractive optical system having a two-dimensional structure, which can be used as a phase shift mask for the fabrication of an optical element having a two-dimensional fine periodic structure, and a two-dimensional light beam splitter. The diffractive optical system 10 comprises a transparent substrate surface 1 that is divided in alignment with orthogonal two directions into minuscule square cell groups 2, 3 of the same shape in a checked pattern. The square cells that give a phase 2ppi and a phase {(2q+1)pi�deltapi} where 0<=delta<=0.25 and p and q are each an integer with respect to reference-wavelength light striking vertically on the transparent substrate surface 1 are alternately arranged in each direction, and the phase 2ppi-giving square cells and the phase {(2q+1)pi�deltapi}-giving square cells are located in such a way as to be in alignment with 45� diagonal directions of said two directions. |
