Zinc selenide (ZnSe) has become the most commonly used material for extreme environment and rugged sampling applications.  Reflective losses due to its high refractive index can be reduced to near zero with the use of our Photon Pro™ coating. In fact, the reflective losses can be reduced to less than that of KBr.  Thus, when operations in tough environments are required and the low frequency ZnSe bulk material limit of 600 cm-1 is acceptable, our Photon Pro coating for our ZnSe beamsplitters provides performance improvements over KBr!