Rainbow Research Optics, Inc. offers many lens options and can quickly address customer requirements for fast lens prototyping. Stock materials are as follows: BK 7 and synthetic fused silica, e calcium fluoride (CaF2), germanium (Ge), magnesium fluoride (MgF2), silicon (Si), zinc selenide (ZnSe), and zinc sulfide (ZnS).  Selecting a suitable optical material is critical to maximizing light transmitting through a lens element.  To select your lens visit online at www.rainbowoptics.com.