| 摘要 |
PROBLEM TO BE SOLVED: To obtain a reflection type diffraction grating which is excellently mass-produced through simple processes, has high diffraction efficiency and large wavelength separation effect over a wide wavelength range, and is reliable. SOLUTION: The reflection type diffraction grating has a grating, made of a flat light-transmissive material which has a projection/recess cross-sectional shape and substantially flat surfaces on tops of projection portions, on a substrate having on its surface an optical reflective surface formed of a dielectric multilayer film formed by laminating a transparent dielectric film having a relatively large refractive index and a transparent dielectric film having a relatively small refractive index by turns, the ration P/λof the wavelengthλof incident light to a grating interval P is 0.55 to 1.45. The light is incident obliquely on the optical reflective surface. COPYRIGHT: (C)2009,JPO&INPIT
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