Stacked diffraction optical element including an optical element made of organic-inorganic composite resin material

A stacked diffraction optical element, comprising:

• a first diffraction optical element that is made of an organic-inorganic composite resin material, and has one surface thereof being a diffracting surface having a diffraction shape;
• and
• a second diffraction optical element that has one surface thereof being a diffracting surface having a diffraction shape,
• wherein the first diffraction optical element and the second diffraction optical element are disposed so that the diffracting surfaces thereof are opposed to each other and are in contact with each other,
• wherein the organic-inorganic composite resin material comprises metal oxide fine particles and a resin, which is a cured product of a polymerizable organic compound,
• wherein the first diffraction optical element has a refractive index (nd) of 1.61 to 1.65, an Abbe's number (νd) of 13 to 20, and an anomalous dispersion characteristic (θg,F) of 0.42 to 0.54,
• wherein the second diffraction optical element has a refractive index (nd) of 1.70 to 1.75, an Abbe's number (νd) of 40 to 55, and an anomalous dispersion characteristic (θg,F) of 0.53 to 0.58.