Scott J. Lilley,Jay N. Vizgaitis U.S. Army Night Vision & Electronic Sensors Directorate (United States) Jonathan Everett Optikos Corp. (United States) Robert Spinazzola General Dynamics-Global Imaging Technologies (United States)
The increasing availability of sensors that can image in the 1 to 5 μm region has allowed for systems to be developed that utilize the full spectrum. Current mid-wave infrared (MWIR) systems have typically only imaged in the 3 to 5 μm region, but the new detectors allow imaging in the short-wave infrared (SWIR) and MWIR bands on the same image plane. Night Vision and Electronic Sensors Directorate (NVESD) had a requirement to design and build a multiple field of view (FOV) optical system that could image the 1 to 5 μm spectral band utilizing a single, cooled infrared detector. The primary challenge of designing this particular optical system was to get the 1 to 2 (SWIR) μm band to focus at the same image plane as the 3 to 5 (MWIR) μm band in all FOVs. A three-FOV broadband optical system that can image the 1 to 5 μm band on the same image plane was designed and built. Several optical concepts were looked at, and it was decided that a combination of a reflective afocal and refractive imager was the best way to meet the system requirements. The use of a catadioptric system with a single focal plane that images in the 1 to 5 μm spectrum reduces the size of the system and provides the user with see-spot capability.