Beam Splitters

Polarizing Beam Splitters are an optical device used in various applications to divide a beam of light into two separate beams with distinct polarization states. They are an important component in many optical systems, including microscopy, interferometry, laser systems, and telecommunications.

The basic function of a polarizing beam splitter is to transmit light of a certain polarization while reflecting light of orthogonal polarization. It splits an incoming unpolarized or randomly polarized light beam into two separate output beams: one that retains its original polarization and another that has its polarization perpendicular to the input polarization.

Polarizing beam splitters are constructed using birefringent materials or thin films that exploit the polarization-dependent reflection and transmission properties. The most common type of polarizing beam splitter is made using a combination of a dichroic prism or cube and a thin film polarizer.

The unpolarized or randomly polarized light enters the Polarizing Beam Splitter. The incoming light beam then encounters a dichroic plate, prism or cube, which is made of a birefringent material like calcite or other appropriate crystals. The crystal structure of these materials causes them to exhibit different refractive indices for light polarized parallel and perpendicular to a specific axis. In combination with the dichroic prism/cube, a thin film polarizer is often used to enhance the polarization separation. The thin film polarizer is designed to reflect one polarization state while transmitting the other.

As the light passes through the dichroic prism or cube, its polarization is split into two orthogonal components. One polarization component is transmitted through the prism/cube and the thin film polarizer, while the other polarization component is reflected by the thin film polarizer. The two polarized components of light exit the PBS as separate beams with distinct polarization states. One beam retains the original polarization, and the other beam has its polarization state rotated by 90 degrees.

Polarizing beam splitters are essential tools in optical systems where the separation or manipulation of polarized light is required. They find applications in polarimetry, imaging systems, laser setups, and other fields where precise control over polarization is necessary.

Firebird Optics offers them in both plate and cube configurations for both polarizing and non-polarizing applications. Beam splitters are constructed from high quality glass, calcite and other birefringent materials with tight tolerances on both surface flatness and quality, enabling them to be used in laser applications.