KENLEY, England, July 26, 2016 — Optical Surfaces Ltd. has announced vacuum-compatible beam expanders for high-power laser applications. The expanders are aspheric mirror-based devices offering either beam expansion or reduction capabilities. Incorporating high precision off-axis mirrors, they provide an unobstructed output and highly efficient transmission and can be used with collimated polychromatic light without the need of any fine focus adjustment. Available in a wide range of fixed or variable magnification configurations, the beam expanders are designed to be easy to use for accurate, unobstructed expansion and contraction of any collimated input light source. Manufactured to >5 λ surface accuracy, the expanders feature an off-axis design that produces no central obscuration. Efficient transmission is obtained, unspoiled by spider diffraction patterns. The devices incorporate smooth-running mechanics that do not require lubrication, optical designs that avoid use of glues and cements that might outgas and sandblast finished metalwork that eliminates stray light without the need for anodizing.