Patent ID: 8885254

Claim:
A laminated diffractive optical element comprising: plural diffraction gratings laminated with each other, the respective diffraction gratings being formed of a same light-transmissive material; and plural reflective films formed on grating surfaces of the respective diffraction gratings, each of the reflective films being disposed between the diffraction gratings, wherein each of the reflective films reflects light in a specific wavelength range and transmits light in a wavelength range different from the specific wavelength range, the specific wavelength ranges for the respective reflective films being different from each other, wherein the grating surfaces of the respective diffraction gratings are formed in mutually different blazed shapes according to the specific wavelength ranges for the respective reflective films, and wherein the grating surfaces include at least (a) a first grating surface that diffracts and reflects a first light in a first wavelength range as the specific wavelength range and transmits, without diffracting, light in a wavelength range other than the first wavelength range and (b) a second grating surface that diffracts and reflects a second light in a second wavelength range as the specific wavelength range and transmits, without diffracting, light in a wavelength range other than the second wavelength range.