| 摘要 |
PROBLEM TO BE SOLVED: To provide an absorption type wire grid polarization element which has low reflection and a sufficient extinction ratio.SOLUTION: A polarization element has a periodic structure composed of metal and i kinds, equal to or larger than one kind, of dielectric medium on a substrate surface of a dielectric substrate. The periodic structure has a linear grating structure in which a metal grating made of metal and a dielectric grating made of a dielectric medium are linearly arrayed at a grating period smaller than the wavelength of incident light. Here, n≥1.0, k≥2.0, 0.01≤FF≤0.25, n≥1.40, and h≥250 [nm] are satisfied, where h is the overall height of the gratings, nare refractive indexes as real parts of a complex refractive index of the metal, kis an extinction coefficient as an imaginal part, nis an average refractive index of the dielectric grating, and FF is an average occupation rate of the metal gratings. |
