Optical Beam Expander

An optical beam expander also known as a collimator or up collimator is a two or more element optical system that changes the divergence characteristics and the size of the beam.

Optical beam expander.

Beam expander from shanghai optics. Usually beam expanders are used to increase the diameter of laser beams. For more than 75 years edmund optics eo has been a leading producer of optics imaging and photonics technology. A beam expander can enlarge an input beam by the factor m but it can also reduce it by the factor 1 m with a reversed optical beam path.

Beam expanders are optical systems for increasing or decreasing the diameter of a laser beam. Beam expanders are optical devices which increases the diameter of the input beam to produce a larger output. In most cases a beam expander is realized as an optical telescope consisting of two lenses in rare cases of two curved mirrors. Thorlabs galilean type beam expanders which are available in both fixed and variable magnification options are offered for use in the uv visible near infrared and mid infrared spectral ranges.

For the 2x 5x zoom models the expansion ratio can be adjusted from the minimum to the maximum value via one full rotation of the zoom control. A keplerian telescope consists of two focusing lenses where the distance between the two lenses is the sum of their focal lengths. There are many ready made beam expanders available on the market but often they are not available in the required expansion ratio or spectral range. Laser beam expanders increase the diameter of a collimated input beam to a larger collimated output beam for applications such as laser scanning interferometry and remote sensing.

They are also used to reduce the beam diameter which may be useful when using acousto or electro optic modulators. Thorlabs variable magnification galilean beam expanders are available with either a 2x 5x or a 5x 10x continuously variable beam expansion ratio. They take a beam of light and expand its size. Contemporary laser beam expanders are afocal systems developed from well established optical telescope fundamentals.

Two different configurations are common. The fixed magnification sliding lens beam expanders are offered with optics that have either narrowband or wideband ar coatings. When the design input diameter of the beam expander matches the actual input beam diameter system performance will be optimized. A beam expander will have a design input diameter as well typically a diameter smaller than the maximum input diameter where the optical performance of the beam expander is optimized.