OPTICAL MATERIAL AND OPTICAL ELEMENT, DIFFRACTIVE OPTICAL ELEMENT, LAMINATED DIFFRACTIVE OPTICAL ELEMENT, AND OPTICAL SYSTEM

PROBLEM TO BE SOLVED: To improve diffraction efficiency in each working wavelength region within the entire visible region of a diffractive optical element and to prevent concentration of diffracted light beams of a specific order and occurrence of a flare. SOLUTION: The optical element is designed to use an optical material having such a relation between a refractive index (nd) and an Abbe number (vd) with respect to a d-line as nd>-6.667×10-3vd+1.70, and the Abbe number (vd) as vd≤16. As a result, the optical element is obtained in which the diffraction efficiency is improved in each working wavelength region within the entire visible region, and in which light beams of a specific order (design order) are concentrated in the entire working wavelength region. COPYRIGHT: (C)2004,JPO