Silicon beam splitter for far-infrared and terahertz spectroscopy.

Silicon beam splitters several millimeters thick offer numerous advantages over thin freestanding dielectric beam splitters. For routine spectroscopy for which resolutions of better than 1 cm(-1) are not required, a silicon beam splitter can replace several Mylar beam splitters to span the entire far-infrared region. In addition to superior long-wavelength performance that extends well into the terahertz region, the silicon beam splitter has the additional advantage that its efficiency displays little polarization dependence.