Sapphire Infrared Window 25.4mm 3-5um MWIR Thermal Imaging Camera Grade

This sapphire infrared window is engineered for thermal imaging cameras operating in the 3-5μm mid-wave infrared band, where sapphire is the established material of choice. The window transmits above 85% in the 3-5μm range without coating, and with an optional MWIR anti-reflective layer, transmission rises above 93%, maximizing the signal that reaches the thermal detector. For uncooled and cooled thermal imaging systems alike, a sapphire infrared window protects the delicate sensor while preserving the thermal contrast that drives detection performance.

The sapphire substrate is grown as a single crystal, which gives the thermal imaging window uniform refractive index, low scatter, and consistent performance across the full aperture. Each window is polished to a 40-20 scratch-dig surface quality and verified for IR transmission with a spectrophotometer before release. The thermal imaging camera window is available in diameters from 5mm to 100mm with custom thickness, edge profiles, and mounting features such as counterbores or through-holes. Our team also supports system designers with coating selection for 3-5μm, 8-12μm dual-band, or laser protection applications.

Thermal imaging systems are only as good as the window in front of the sensor, because any absorption or scatter in the window directly reduces the temperature resolution of the camera. This sapphire infrared window is therefore specified with measured IR data rather than calculated values, and the same substrate lot is used within each production batch to keep refractive index consistent. For high volume camera programs, the sapphire infrared window can be supplied with pre-applied gaskets or adhesive-ready surfaces, reducing assembly time. Field experience across surveillance, industrial, and automotive programs confirms that single crystal sapphire maintains its IR transmission and surface quality over years of outdoor exposure.