MSE PRO Assembly Laser Beam Expanders

MSE PRO™ Assembly Laser Beam Expanders

MSE supplies offers Assembly Laser Beam Expanders. This beam expander is an optical system for changing the diameters of input and output beams. The product of the diameter and divergence for a laser beam remains constant between input and output. This means that, if the beam diameter increases from input, the divergence of the output will decrease. Beam expanders use this inverse-proportional relationship between the diameter and divergence to expand a laser beam, or to reduce the beam divergence. Low divergence allows for a smaller focus spot of a Gaussian beam. In summary, beam expanders are used for fine focusing, reducing beam divergence and minimizing diffraction effect.

Beam expanders consist of two lens groups that have their focal points aligned in a focal system. One lens group serves as the input and the other as the output. There are two types of beam expanders - Galilean and Keplerian - which differ based on the input lens used. While Galilean beam expanders are more common and typically have one negative and one positive lens, Keplerian beam expanders use two positive lenses. Galilean beam expanders are often preferred for expansion ratios less than 20x due to their simplicity, small size, and affordable cost. However, they are limited in their ability to accommodate spatial filters and higher expansion ratios. In situations where these requirements are necessary, Keplerian beam expanders are used, featuring two positive lenses with the first lens's rear focal point aligned with the second lens's front focal point. Additionally, spatial filtering can be achieved by incorporating a pinhole at the coinciding focus point.

MSE Supplies can offer a variety of optical elements, with different focal length and coating options. Please contact us for customization or bulk orders. 

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