They can be used to split unpolarized light at a 50/50 ratio, or for polarization separation applications such as optical isolation (Figure 3). A beam splitter or beamsplitter is an optical device that splits a beam of light into a transmitted and a reflected beam. It is a crucial part of many optical experimental and measurement systems, such as interferometers, also finding widespread application in fibre optic telecommunications. Beamsplitters are often classified according to their construction: cube or plate. 📦 For purchasing, use the RP Photonics Buyer's Guide for beam splitters. It provides an expert-curated supplier directory, buyer-focused technical background information, and structured selection criteria to support professional procurement decisions. Characteristics of Beam Splitters 3.