Why should I choose a Reflective Beam Expander instead of a Refractive Beam Expander?

Reflective laser beam expanders are achromatic by design. This enables them to easily be used for broadband applications including those using multiple laser wavelengths or for tunable lasers. This achromatic nature makes them ideally suited for ultrafast applications or for wavelengths that are difficult to find transmissive designs for, such as certain QCL wavelengths.