Patent ID: 8437238

Claim:
An aberration correction element, comprising: a convex portion; and a concave portion, wherein the convex portion and the concave portion function with lights having different wavelengths λ 1 , λ 2 , and λ 3 , wherein the convex portion and the concave portion are alternately disposed on at least one surface of a substrate with a predetermined pitch, wherein an average refractive index of the convex portion is smaller than an average refractive index of the concave portion, and when phase differences of the lights having the wavelengths λ 1 , λ 2 , and λ 3 , which are transmitted through the convex portion and the concave portion are, respectively, a 1 π, a 2 π, and a 3 π, 0 ≦|a 1 −a 2 |≦0.2, 0.2 <|a 3 −a 1 |, and 0.2 <|a 3 −a 2 |, are satisfied.