Design of a mid-wave infrared AOTF-based spectral imaging system

Acousto-optic tunable filter (AOTF) imaging spectral detection systems are capable of simultaneously acquiring image, spectral, and polarization information. They have been successfully applied in fields such as aerospace and demonstrate promising development prospects. Meanwhile, infrared imaging detection systems, owing to their advantages such as strong anti-interference capability and resilience to adverse weather conditions, have become a key development focus for various nations. An MWIR AOTF spectral imaging system was designed. The system primarily consists of a front afocal lens group, the AOTF, a rear imaging lens group, a cooled MWIR detector, an AOTF RF driver, and a host computer. The optical parameters of the subsystems (front mirror group, collimating lens group, and rear reimaging group) were first calculated. Simulation results demonstrate that within the operating wavelength range of 3.7∼4.8μm, at a focal length of 120 mm, F-number of 4, and a field of view of 5°× 4°, the system's Modulation Transfer Function (MTF) values approach the diffraction limit across the working spectral band and are above 0.3, while distortion is less than 2%. This indicates good imaging quality.