Collimating optical system for deploying infrared scene projection in low-radiation background

To achieve hardware-in-the-loop simulation testing for infrared seeker cameras, a collimating optical system for mid-to-long wavelength applications and deployment in infrared scene projection under low-radiation backgrounds is proposed. The system adopts an off-axis Three-Mirror Anastigmat (TMA) optical configuration to cover the imaging field of view of the seeker camera (>= 2 degrees). The opto-mechanical system uses SiC material to achieve athermal design, minimizing changes in the opto-mechanical structure and optical performance due to temperature variations. A low thermal conductivity insulation support structure and a cryogenic radiative cooling panel are used to achieve uniformity and rate of cooling for the optical system. Flexible bolt components compensate for bidirectional displacement and structural stress caused by temperature changes. Simulation and experiment indicate that the optical system can rapidly cooling to a low-radiation background environment below -143 degrees C within 48 h. Additionally, experiments verified that under a low- radiation background, the wavefront error RMS of the collimating optical system meets the requirements for the application wavelength band, enabling the completion of testing tasks for the infrared seeker camera.