Optical Surfaces vacuum compatible reflective beam 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. Reflective beam expanders use mirrors which have constant focal lengths, regardless of the light being focused. Thus, they can be used with collimated polychromatic light without the need of any fine focus adjustment. Available in a range of fixed or variable magnification configurations – the beam expanders are designed to be easy to use and to provide accurate, unobstructed expansion/contraction of any collimated input light source. They are also portable and can be used without the need for internal re-alignment.
Each beam expander is supplied housed in aluminium with provision for fixing to an optical table. Alignment aids are provided to ensure correct beam pointing. Manufactured to better than lambda/5 surface accuracy, the off-axis design produces no central obscuration and efficient transmission is obtained, unspoilt by spider diffraction patterns. An interferogram and OPD map is supplied with every product.