ZnSe plano-concave lenses are an optical element made of ZnSe material. They are negative lenses that can disperse light. The applications of these lenses include biomedical and military applications, as well as applications used with high-power CO2 lasers. In addition, they provide sufficient transmittance in the visible region to allow the use of red alignment beams.  Zinc selenide has low absorption and thermal shock resistance, and its transmission band is wide (600nm-16μm). It has low absorption in the red light part of the visible spectrum, so it is often used in optical systems that combine CO2 lasers (working at 10.6μm) with inexpensive helium-neon lasers.