diffractive optical element, optics and optical instruments

摘要

PROBLEM TO BE SOLVED: To provide a diffractive optical element which allows the reduction of transmittance difference in a single grating while providing high diffraction efficiency, an optical system, and an optical device.;SOLUTION: In a diffractive optical element 10 formed by laminating first and second diffraction gratings 1 and 2 each of which is made of two different materials, a difference between extinction coefficients for a d line of two materials 11 and 12 constituting the first diffraction grating is more than 0.0002 and less than 0.002, and a difference between extinction coefficients for a d line of two materials 21 and 22 constituting the second diffraction grating is more than 0.0002 and less than 0.002, and the materials 11, 12, 21, and 22 satisfy 0.05|Δnd1|0.3, 0.05|Δnd2|0.3, 20|Δνd1|40, and |Δνd2|15 wherein Δnd1 is a difference between refractive indexes for the d line of the materials 11 and 12, Δnd2 is a difference between refractive indexes for the d line of the materials 21 and 22, Δνd1 is a difference between Abbe numbers of the materials 11 and 12, and Δνd2 is a difference between Abbe numbers of the materials 21 and 22.;COPYRIGHT: (C)2013,JPO&INPIT