Cube Beamsplitter

A type of beamsplitter constructed of two cemented right angle prisms, one with a broadband multi-layer dielectric coating on the hypotenuse. 50% of incident light is transmitted, and 50% is reflected. Outside surfaces have an anti-reflection coating to reduce back reflections. No beam displacement occurs between the original and separated beams. The reflected and transmitted beams travel through the same amount of glass, so although the optical path length of each arm is increased, both paths are increased by the same amount. Their cubic shape makes cube beamsplitters easy to mount, thus suffering less from deformation due to mechanical stress.