Beamsplitters are designed to separate an incoming or incident light into two components consisting of a reflected and transmitted beam.  Designs may be optimized for specific reflection and transmission ratios, wavelengths, angle of incidence and polarization state.














The amount of reflectivity can be adjusted to a specific value.
For example a mirror that reflects 50% and transmits 50% of light focused on it over a range of wavelengths.



Iconel Beam Splitter

Partially transmitting metals make very useful beam splitter coatings.  Beam splitters are often very broad and can cover a much wider spectrum of wavelengths than their dielectric counterparts.  This example shows a single layer coating with approximately equal reflectance and transmittance.