Beam expanders – Choose a model with 2 or 3 lenses?

Many laser systems have a beam expander to change the diameter of the beam from the source to match the requirements of the optical system.  Most beam expanders have two or three lenses to accomplish the task.  While three lenses will provide less beam distortion, every lens causes some loss of light.

One might sacrifice beam quality with two lenses to get more light through the beam expander but there is another solution.  Geomatec uses three lenses in their beam expanders for low distortion but the famous Geomatec optical coatings have exceptionally low light loss.  The Geomatec beam expanders have > 98% light transmission even though they have three lenses.  Maximum light transmission is important when using high power lasers for material processing because light that is not transmitted is absorbed by the optics.    Minimal beam distortion is critical when a system is focusing to a very small spot and/or beam shaping is being used to achieve a top hat / flat top or donut profile.   Every Geomatec beam expander is tested for light transmission and for distortion with a beam profiling camera.

These are some of the reasons why Geomatec is the largest supplier of beam expanders in Japan and a major supplier of F-Theta lenses as well.  See complete specifications here:  BEAM EXPANDERS    F-THETA LENS

These high quality Geomatec beam expanders and F-Theta lenses are available through Precision Laser Scanning with short lead time and attractive prices.