Polarizing Beamsplitters

A polarizing beamsplitter is an optical component that is designed to split light into two directions, dividing it by polarization state.  Most polarizing beamsplitters are designed for incident light to enter at a 0° or 45° angle and will separate the two polarized beams of light at a 90° angle. Where two displaced parallel beams are required, a lateral displacement beamsplitter can be used. Avantier is a premium source for all your custom beamsplitter needs, and our experienced optical engineers and designers can help you determine the perfect beamsplitter for your needs.

Polarizing Beamsplitters


Types of Polarizing Beamsplitters

Polarizing beamsplitter can be divided into three kinds: plate polarizing beamsplitters, cube beamsplitters, and lateral displacement beamsplitters.  All three types separate the light radiation into two beams with orthogonal polarization.  The ratio of reflected to transmitted light in a perfect beamsplitter will always be 50/50.

  • Plate polarizing beamsplitters  are typically designed with special hard coatings on the front surface of an optical substrate like UV fused silica. As they have a high damage threshold, they are a good choice when high transmission, a high extinction ratio, and a high damage threshold are necessary.  A plate beamsplitter has a distinct front and back side and  is designed to be used at a 45 degree angle of incidence. Typically, a small arrow will be engraved on the beamsplitter to show the appropriate direction of light.  S-polarized will be reflected at 45 degrees, while p light will be transmitted. 
  • Polarizing cube beamsplitters are formed from two prisms, one of which has a dielectric beam splitting coating on the hypotenuse side. The two prisms are placed with hypotenuse sides against each other and  bound together with optical cement.  Light may enter at any of the polished square faces of the cube, which will split light into s and p polarized beams. These polarizing beamsplitters are a great choice when you need a durable beamsplitter or would like simplified mounting and system integration.  They are typically manufactured with a broadband anti-reflection coating on all faces. For laser line cube beamsplitters, our clients may choose between AR coatings optimized for  532 nm, 633 nm, 780 nm, 980 nm, 1064 nm, or 1550 nm laser wavelengths. 
  • A lateral displacement beamsplitter is formed by a rhomboid prism cemented to a λ/8 right angle prism. Both entrance and exit faces will typically be coated with high quality anti-reflection coatings as well as polarizing coatings. This type of beamsplitter is less common than cube or plate beamsplitters, but is highly desirable to simplify bench top layout.

Applications of Polarizing Beamsplitters

Polarizing beamsplitters are important components of any system that requires the separation of s- and p-polarized light. For instance, in semi-conductor and photonics instrumentation a beamsplitter  transmits p-polarized light and reflects s polarization light. Polarizing beamsplitters are also incorporated in optical isolators to eliminate feedback-induced damage, as the transmitted beam consists fully of polarized light.


Factory Standard

  • Material: Schott, Ohara, CDGM Optical Glass, Corning fused silica, JGS1, JGS2
  • Surface flatness: λ/4
  • Dimensions: +0.1 mm
  • Beam deviation: < 5 arcmin
  • Surface quality: 40-20
  • Extinction ratio: 100:1

Custom Polarizing Beamsplitters at Avantier

At Avantier, we are able to design and manufacture  plate beamsplitters (in both round and rectangular configurations), cube polarizing beamsplitters, and lateral displacement beamsplitters.  A variety of substrates and coating options allow us to customize your polarizing beam splitter order for desired wavelength ranges and power handling requirements. 

Our beamsplitters have an extinction ratio of 100:1 and a high surface quality and surface flatness. We can also produce Brewster windows and birefringent crystals that are highly resistant to laser damage for polarization cleanup in potentially compromising situations. 

Please contact us for more information on our manufacturing capabilities or to schedule an introductory consult.


Contact us NOW for sales & expert advice.