Optical element, objective optical element and optical pickup device

摘要

An optical element (10) comprises: a diffractive structure having a plurality of diffracting ring-shaped zones (21) arranged around an optical axis on at least one optical surface; and an optical path difference giving structure (30) arrranged on an optical surface of at least one of the plurality of diffracting ring-shaped zones, for giving a prescribed optical path difference to a prescribed light beam passing through the diffracting ring-shaped zone, wherein the optical surface of the diffractive structure is a structure having a diffracting function for setting L-th (L NOTEQUAL 0) order diffracted light of the light beam having the first wavelength lambda 1 to a maximum diffraction efficiency and for setting M-th (M NOTEQUAL 0) order diffracted light of the light beam having the second wavelength lambda 2 to a maximum diffraction efficiency in case of an assumption of no existence of the optical path difference giving structure.