| 摘要 |
To provide a broadband reflecting mirror having high reflectance within a wavelength band of 400 nm to 2500 nm and having excellent thermal resistance and damage resistance. A broadband reflecting mirror 1 for reflecting light within a wavelength band of 400 nm to 2500 nm includes: a first reflective layered coating 3 for reflecting light in a short wavelength side of the wavelength band of 400 nm to 2500 nm, the first reflective layered coating including first high-refractive index material and first low-refractive index material layers alternately stacked one on another; and a second reflective layered coating 4 for reflecting light in a long wavelength side of the wavelength band of 400 nm to 2500 nm, the second reflective layered coating including second high-refractive index material and second low-refractive index material layers alternately stacked one on another, wherein the first reflective layered coating 3 is disposed on the light-incident side of the broadband reflecting mirror and the second reflective layered coating 4 is disposed at a position where light having passed through the first reflective layered coating 3 can be reflected, and wherein the first high-refractive index material layer is formed of at least one material selected from the group consisting of niobium oxide, titanium oxide, zirconium oxide, tantalum oxide, hafnium oxide, silicon nitride, yttrium oxide and indium tin oxide, the first low-refractive index material layer is formed of at least one material selected from the group consisting of silicon oxide and magnesium fluoride, the second high-refractive index material layer is formed of at least one material selected from the group consisting of silicon and germanium, and the second low-refractive index material layer is formed of at least one material selected from the group consisting of silicon oxide and magnesium fluoride.
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