Diffractive optical element, method for producing diffractive optical element, optical device, and image pickup apparatus

A method for producing a diffractive optical element, comprising:

• forming a first resin layer having a diffraction grating shape by disposing a thiol group-containing first resin composition on a first substrate;
• and
• forming a second resin layer having a diffraction grating shape by disposing a second resin composition on the first resin layer,
• wherein in forming the second resin layer, the second resin composition is cured to satisfy α<β, where α is a ratio of intensity of a peak corresponding to a sulfide group to intensity of a peak corresponding to the thiol group in a first region of the first resin layer, the first region containing no interface between the first resin layer and the second resin layer, and β is a ratio of intensity of a peak corresponding to the sulfide group to intensity of a peak corresponding to the thiol group in a second region containing an interface between the first resin layer and the second resin layer, the second region being smaller than a total thickness of the two resin layers, these peaks being measured by laser Raman spectroscopy.