Dual-band infrared optical system with large field-of-view and aperture

Infrared optical systems are widely applied in military and public security fields. Since the radiation energy of infrared objects is lower, the corresponding optical system must have a large numerical aperture in order to increase the system exploring sensitivity, and it also needs to provide a large field of view in order to remove the traditional scanning mechanism. This study described the optical design of an infrared system with a field of view of 60 x 3.5 degrees and an F-number of F/2.5-F/1. The design is based on a fast unobscured three-mirror anastigmatic(TMA)system. The final optical system is a three-mirror unobscured system. It has a simple structure and the quality of image arrives at the diffraction-limitation at infrared wavelengths.