Optical multilayer thin film and beam splitter

• Main Author: ITO; TAKU
• Format: Patent
• Language: English
• Published: 21.03.1995
• Edition: 6
• Subjects: OPTICAL ELEMENTS, SYSTEMS, OR APPARATUS; OPTICS; PHYSICS

An optical multilayer thin film and a beam splitter having an optical multilayer thin film are disclosed. The optical multilayer thin film is formed by laminating six layers in sequence. The laminated six layers comprise: a first layer, a third layer and a fifth layer each having a refractive index between 1.63 and 1.64; a second layer and a sixth layer each having a refractive index between 1.37 and 1.38, a fourth layer having a refractive index between 1.9 and 2.3; in which light is allowed to be incident upon the first layer of the optical multilayer thin film at the angle of incidence equal to or greater than 40 DEG . In the beam splitter, the reflectances of S and P polarized components of reflected light are substantially equal to each other over a wide wavelength range and substantially no phase difference exists between the S and P polarized components. Further a beam splitter having a multilayer polarizing light separating film formed between an incoming side prism and an outgoing side prism is also disclosed, which is extremely high in the reflectance of the P polarized component of reflected light, in comparison with that of the S polarized component of the same reflected light.