Figure 4: Intrinsically, a beam splitter has two inputs — whether or not both are used. A beam splitter or beamsplitter is an optical device that splits a beam of light into a transmitted and a reflected beam. It is a crucial part of many optical experimental and measurement systems, such as interferometers, also finding widespread application in fibre optic telecommunications. Beamsplitters are often classified according to their construction: cube or plate. Output states from beam splitters under different inputs such as single photons entering through one port, two photons entering through the two input ports, single photon in a multimode state, and entangled photons are discussed. Field 1 evolves as E1 ! T E3 + RE4, where T; R are the transmission and re ection coe cients for the beam splitter. The specific parameter symbols shown in the figure have the.
