Patent ID: 8094394

Claim:
An optical filter that transmits or reflects light of a first wavelength, the optical filter including: a dielectric substrate; a first metal structure group in which a plurality of first metal structures are arranged two-dimensionally in an isolated state in the in-plane direction of the dielectric substrate, that is provided on a surface of the dielectric substrate; and a dielectric layer with which the first metal structure group is covered, wherein the first metal structures have a first length in a first direction and a second length in a second direction orthogonal to the first direction, the first length and the second length being less than or equal to the first wavelength, wherein a transmittance of the first wavelength is made minimal or a reflectance of the first wavelength is made maximal by localized surface plasmons induced on a surface of the first metal structures by resonance between light incident on the dielectric substrate or the dielectric layer and the first metal structures, and wherein the first length and the second length are within a range of 110 nm or more and 160 nm or less, a thickness of the first metal structures is within a range of 10 nm or more and 100 nm or less, a period at which the first metal structures are arranged is within a range of 340 nm or more and 450 nm or less, and the first wavelength is within a range of 550 nm or more and less than 650 nm.