Optical Beam Expander

Two different configurations are common.

Optical beam expander.

How to build a beam expander beam expansion or reduction is a common application requirement in most labs using lasers or light sources and optics. Beam expanders are optical devices which increases the diameter of the input beam to produce a larger output. 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. Beam expanders are optical systems for increasing or decreasing the diameter of a laser beam.

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 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. 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. Our fixed magnification rotating lens optical beam expander.

Beam expander from shanghai optics. A keplerian telescope consists of two focusing lenses where the distance between the two lenses is the sum of their focal lengths. Contemporary laser beam expanders are afocal systems developed from well established optical telescope fundamentals. 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.

The fixed magnification sliding lens beam expanders are offered with optics that have either narrowband or wideband ar coatings. For more than 75 years edmund optics eo has been a leading producer of optics imaging and photonics technology. They are also used to reduce the beam diameter which may be useful when using acousto or electro optic modulators. They take a beam of light and expand its size.

Usually beam expanders are used to increase the diameter of laser beams. Thorlabs variable magnification galilean beam expanders are available with either a 2x 5x or a 5x 10x continuously variable beam expansion ratio. 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. In most cases a beam expander is realized as an optical telescope consisting of two lenses in rare cases of two curved mirrors.