AR Coated Germanium IR Lens 3-5um MWIR High Transmission 25.4mm Optics

This AR coated germanium IR lens is designed for 3-5um MWIR systems that demand high transmission and stable imaging. The 25.4mm lens is fabricated from optical grade single crystal germanium, the standard substrate for mid-wave infrared optics, and coated with a dedicated MWIR anti-reflective layer that lifts transmission above 97 percent across the 3-5um band. Without the IR coating, germanium reflects roughly 36 percent of incident light from its surfaces; this AR coated germanium lens eliminates that loss and keeps the maximum signal on the detector.

Each germanium IR lens is polished to a 40-20 scratch-dig surface quality and verified with an FTIR spectrophotometer, and the measured transmission curve is supplied with the batch. The lens is available in plano-convex, bi-convex, and meniscus geometries, with focal lengths matched to collimating, focusing, and imaging roles in MWIR systems. Custom diameters from 5mm to 100mm, alternate coatings for 8-12um LWIR or dual-band operation, and mounted versions with threaded housings are available for OEM thermal imaging programs.

The AR coated germanium IR lens is used across thermal imaging, temperature measurement, and infrared spectroscopy applications where signal loss in the optical path directly reduces measurement accuracy. Because germanium is sensitive to thermal runaway above roughly 100 degrees Celsius, the lens is also available with a hardened protective coating and is typically specified for ambient-temperature system environments. Design teams receive recommended handling and mounting guidance, including torque limits for threaded housings, so the lens performs to specification in production assemblies. Batch traceability records link each lens to its material lot, coating run, and inspection data, which supports quality programs in medical, industrial, and defense supply chains.