Athermal Lenses

https://www.cngeir.com/products/athermal-lenses/

MWIR athermal lens is a high-end optical device specifically designed for imaging systems in the medium wave infrared (MWIR) band. These MWIR athermal lenses are often used in areas that require high precision and sensitivity in infrared imaging, such as military reconnaissance, security surveillance, scientific research, and industrial inspection. Athermalization refers to a feature in athermal lens design that allows the athermal lens to maintain good image performance under different temperature conditions without focus shift or image quality degradation due to temperature changes.