Optical material, and optical element, optical system, and laminate type diffraction optical element, which are made of optical material

摘要

To provide an optical element in which the diffraction efficiency in each use wavelength region within the entire visible region is preferable, and light beams of a specific order (design order) are sufficiently concentrated in the entire use wavelength region, by using an optical material in which the relationship between a refraction index n_d and an Abbe number nu_d with respect to a "d" line is n_d>-6.667x10^-3nu_d+1.70 and the Abbe number nu_d satisfies nu_d<=16.