| 摘要 |
PROBLEM TO BE SOLVED: To obtain a beam splitting film which reduces the wavelength dependency and the incident angle dependency of the branching ratio, and to obtain a beamsplitter using the same. SOLUTION: The beam splitting film is used for branching a prescribed wavelength region of a polarized beam to transmission light and reflection light, and has a multilayer structure obtained by laminating a first thin film formed from a high refractive index material, a second thin film formed from a low refractive index material, and a third thin film formed from a material having an intermediate refractive index within the range of between the refractive index of the high refractive index material and the refractive index of the low refractive index material, wherein the high refractive index material is silicon, while the low refractive index material is at least one kind selected from silicon oxide, magnesium fluoride, and aluminum oxide, and the material having the intermediate refractive index is at least one kind selected from titanium oxide, tantalum oxide, niobium oxide, zirconium oxide, hafnium oxide and aluminum oxide. COPYRIGHT: (C)2010,JPO&INPIT
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