• 10X Beam Expansion
• Diverge, Collimate, or Focus a Beam
• Sliding Collimation Adjustment
• Best Form AR-Coated Lenses
• Damage Threshold: 100 W/cm²
• Removable Endcap Protects C-Mount Threading

This EL series Galilean Beam Expander is designed to expand or reduce the diameter of a collimated beam while introducing a wavefront error of less than ?/4, (i.e. diffraction-limited performance). An expanded beam can be focused to a narrower diffraction limited waist; such a reduced beam is sometimes necessary for use with optics or instruments that have narrow input apertures such as the SA200 family of scanning Fabry-Perot interferometers.

The housing contains two best form lenses that are designed to minimize aberrations in the recollimated beam. Both optics have broadband AR coatings to minimize surface reflections. The input lens is mounted in a precision-milled tube that can slide in and out of the tube containing the output lens. The sliding design allows for the adjustment of the collimating lens and minimizes the beam walk-off effect that is inherent to lens adjustments. The beam expander can be mounted via either the 1/4"-20 or the M6-threaded hole in the base. In addition, the groove milled into the base can be used to clamp the beam expander to an optical table using CL6 mounting cleats (not included). The beam expander has a C-Mount threaded input aperture, which allows additional lenses and filters to easily be installed along the optical axis of the beam expander.

• Average Reflectance: <0.5%
• Magnification: 10X
• T: >96%
• Damage Threshold (CW): 100 W/cm²
• Max Input 1/e² Beam Diameter: 2 mm
• Input Aperture: Ø9 mm
• AR Coating Range: 350 – 650 nm
• Scratch-Dig: 10-5