Instead of a metallic coating, a dichroic optical coating may be used. Depending on its characteristics (thin-film interference), the ratio of reflection to transmission will vary as a function of the wavelength of the incident light.OverviewA beam splitter or beamsplitter is an that splits a beam of into a transmitted and a reflected beam. It is a crucial part of many optical experimental and measurement systems, such as In its most common form, a cube, a beam splitter is made from two triangular glass which are glued together at their base using polyester,, or urethane-based adhesives. (Before these synthetic,. Beam splitters are sometimes used to recombine beams of light, as in a. In this case there are two incoming beams, and potentially two outgoing beams. But the amplitudes.