Beam splitters are classified by construction (plate, cube, pellicle, polka dot) and by function (standard, non-polarizing, polarizing, dichroic). Construction determines ghosting, damage threshold, and form factor. Function determines how polarization and wavelength are. Beamsplitters are optical components used to split incident light at a designated ratio into two separate beams. They are found in different configurations and can be used in multiple applications. It is a crucial part of many optical experimental and measurement systems, such as interferometers, also finding widespread application in fibre optic telecommunications.