| 摘要 |
<p>A diffractive optical element in which the maximum optical path length of light is an integral multiple of each of a plurality of wavelengths includes a diffractive grating configured by combining a first member and a second member having a refractive index lower than a refractive index of the first member and having dispersion higher than a dispersion of the first member. At least one of the first member and the second member is made of a glass material, and the diffractive grating is formed by the glass material which is heated to be softened using a thermal press forming, and has a concave grating shape that has a grating height increasing from a central part toward a peripheral part.</p> |
