Diffraction grating and mold for forming diffraction grating

Abstract

A diffraction grating including: an optically transparent substrate; and a diffraction grating structure, with a step-like cross-sectional shape, on a surface of the optically transparent substrate, wherein the diffraction grating structure is formed of a single member, the diffraction grating structure includes a first diffraction grating portion and a second diffraction grating portion with different grating periods and different numbers of steps, a grating period of the second diffraction grating portion is shorter than a grating period of the first diffraction grating portion, a number of steps of the second diffraction grating portion is more than a number of steps of the first diffraction grating portion, and a difference between a grating height of the first diffraction grating portion and a grating height of the second diffraction grating portion is less than a minimum height of one step of the first diffraction grating portion.

Dependencies are inferred from the claim text.