Beamsplitters are used to split light beams into two separate beams with a designated ration. These optical components can also be used to combine two beams into one. They are classified according to their construction as either cube or plate beamsplitters. A standard beam splitter is designed to split light a specified Reflection/Transmission ratio regardless of the polarization state. Beam splitters are often used with un-polarized light sources in cases where the polarization state is negligible. With this in mind, there are two categories of beam splitters:
- Non-polarizing beamsplitters- These beam splitters can split the original beam of light to the specified reflection/transmission ration without changing the original polarization state of the incident light. They are often used when the source of light is polarized, for instance lasers.
- Polarizing beamsplitters: These beam splitters on the other hand randomly split polarized light. They can also be used as filters to enhance polarized light to a higher level of polarization that increases the extinction ratio.
The types of beamsplitters available today come in various designs for different applications. Let us take a look at a few of these.
The basic cube beam splitter is made up of two prisms that are joined together using epoxy or polyester. The thickness of the material used to join the two prisms is adjusted to reflect half the amount of light that hits the face of the cube while the other half is transmitted out the other end of the cube. Some types of beamsplitters use birefringed materials to split light into different degrees of polarization.
Aluminum coated beamsplitters use a half-silvered mirrors and a sheet of glass with aluminum coating that is deposited from aluminum vapor. The thickness of the coating determines the amount of light that is reflected, absorbed by the coating of transmitted. This beam splitter design uses Swiss-cheese beam splutter mirrors to reduce the amount of light absorbed by the reflective coating.
Dichroic beamsplitters as specially designed to split the incident light by wavelengths. These come in variety of applications such as laser beam combiners, which are designed for specific laser wavelengths. Instead of using metal coating as in the case of the aluminum coated beam splitters, these use a dichroic optical coating. The wavelengths produced depend on the Reflection/Transmission ratio. Sometimes, they are used to split off infrared radiation in ellipsoidal reflector spotlights.
The dichroic-mirrored prism also used dichroic optical coatings to divide incident light into a number of output beams. This type of beam splitter has been used in order versions of TV cameras and movie cameras. Today, they are often used in three CCD cameras. The reverse of the dichroic mirror prism, a beam combiner is also used in LCD projectors to combine different colors to create a full color image for display.
When it comes to beam splitters, Penn optical offers high quality beams splitter solutions. It is essential to choose well-engineered materials for the best results and a high level of efficiency.