Infrared (IR) lenses are optical lenses designed specifically to transmit infrared light, which falls outside the visible spectrum, typically in the wavelength range from around 0.75 microns (750 nm) to 1 mm. Infrared lenses are essential components in infrared imaging, thermal sensing, and laser systems, among other applications. These lenses are made from materials that are transparent to infrared radiation, which allows them to focus or direct infrared light, unlike conventional optical lenses that work primarily with visible light.