ABSTRACT
Beamsplitters split incident light into two separate beams. Alternatively, beamsplitters can be used in reverse to combine two different beams into a single beam. There are three types of beamsplitters: plate, cube, and pellicle. A plate beamsplitter consists of a thin plate, which is coated on the front surface. Plate beamsplitters include dichroic beamsplitters and Polka dot beamsplitters, which are fabricated by depositing squares of aluminum coating on a substrate. Cube beamsplitters consist of two right angle prisms that are cemented together; the hypotenuse of one prism is coated. A polka dot beamsplitter is fabricated by depositing square dots of aluminum coating on a substrate. Non-polarizing and polarizing cube beamsplitters with Reflection/transmissions ratio of 50/50 are also commercially available. Polarizing cube beamsplitters split randomly polarized light into two orthogonal, linearly polarized components. The S-polarized component is reflected, while the P-polarized component is transmitted. Pellicle beamsplitters are made of very thin nitrocellulose film bonded to lapped aluminum frames.
