Germanium is a relatively common optical material. It can be used not only in long-wave infrared, but also in medium-wave infrared. Germanium should be treated carefully in the process of light processing, coating and adjustment. Because germanium has a wide range of uses, compared with its advantages, its problems can be solved.
Silicon is a crystalline material similar to germanium. The refractive index of silicon is lower than that of germanium, which has sufficient advantages in controlling aberration. In addition, the dispersion of silicon is very low. Silicon can be processed by diamond turning, but this is very difficult and harmful; To turning tool. The common processing method is polishing.
Compared with oxide glass, chalcogenide glass has higher density and weaker bonding strength. At present, chalcogenide glasses used in infrared optical devices contain arsenic. However, with the improvement of environmental awareness and product standards in the world; Environmental protection arsenic free glass will become a trend.
Zinc selenide and zinc sulfide are also infrared optical materials. Zinc selenide is more expensive than zinc sulfide, and is suitable for optical systems with low requirements for absorption.
Calcium oxide can be used in optical elements such as prisms, lenses, large-aperture lenses and windows. It can eliminate the secondary spectrum and is conducive to the spectral apochromatic aberration.
Infrared lenses are widely used in night vision, imaging systems and medical devices.