OFR manufactures and stocks standard Beamsplitter plates and prism cubes. As in all of our products, we will specially manufacture on a custom basis to customer’s specifications.

BANDWIDTH OR TRANSMITTANCE, which is more important?

Metallic Coatings
Metallic coatings are achromatic over an extremely wide spectral range. For example, our beamsplitters are designed for equal reflection and transmission when used with unpolarized light at 45°. However, when used with S-polarized light, the R/T ratio is approximately 60/40, and with P-polarized, it is approximately 40/60. Absorption in the metallic coating is 1/3, and it is seen that if reflection equals transmission, then R=T=33%. Our standard metallic coating is vacuum-deposited inconel which forms a tough and relatively scratch-resistant film. It is recognized by its grey and neutral appearance, which is a sure sign of its achromaticity.

Dielectric Coatings
In general, dielectric coated beamsplitters have a narrower bandwidth than the metallic type, and are inherently of negligible absorption loss. In general, dielectric coatings show much more effect upon the R/T ratio of polarized light than do metallic types. Our standard beamsplitters are designed for equal reflectance /transmittance split when used with unpolarized light. However, when used with S-polarized light, the R/T ratio is 70/30, and with P-polarized the split is 30/70.