INFRARED OPTICAL FILTER AND METHOD FOR PRODUCING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide an infrared optical filter which has high flexibility in design of selective wavelengths and also improves filter performance, and to provide a method for producing the same. SOLUTION: The infrared optical filter is provided with: a substrate 1 made of an infrared transmission material (Si); and a plurality of filter parts 21, 22arranged in parallel on one surface of the substrate 1. Each filter part 21, 22is provided with: a first λ/4 multilayer film 21 in which two kinds of thin films 21b, 21a different in refractive index and same in optical film thickness are alternately laminated; a second λ/4 multilayer film 22 formed on the side opposite to the side of the substrate 1 in the first λ/4 multilayer film 21, and in which two kinds of thin films 21a, 21b are alternately laminated; and wavelength selection layers 231, 232lying interposed between the first λ/4 multilayer film 21 and the second λ/4 multilayer film 22 and having optical film thickness different from that of the thin films 21a, 21b in accordance with desired selective wavelengths. As a low refractive index material of the thin films 21b, Al2O3is used, and, as a high refractive index material of the thin films 21a, Ge is used. COPYRIGHT: (C)2010,JPO&INPIT