| 摘要 |
PURPOSE:To decrease the rate of change in the polarizing component with respect to a change in incident angle by providing a three-layered structure coated with semitransparent films on the surface of a thin silver film to a transparent base material thereby constituting a non-polarizing beam splitter. CONSTITUTION:The semitransparent film 3, then thin silver film 4 and further semitransparent film 5 formed on the reflecting surface of a rectangular prism 1 of a beam splitter A using two rectangular prisms 1, 2 are required to be controlled in order to be made non-polarizing. The films 1, 3 can be easily controlled by selecting conditions for vapor deposition of, for example, titanium dioxide, silicon monoxide, etc. Titanium dioxide is superior in the visible region and particularly silicon monoxide is superior in the near IR region. The refractive index of the silicon monoxide changes with the speed of vapor deposition, etc. and therefore the refractive index is controllable as desired within an about 1.5-2.0 range. |
