Design and Experimental Study of Optical System for Ultra-Low Self-Heating Radiation Long-Wave Infrared Laser Communication Optical System

In this study, we design an ultra-low self-heating radiation long-wave infrared laser communicationoptical system, which mainly includes aperture stop, primary mirror, secondary mirror, three-mirror,field stop, four-mirror, window glass, detector light shield, and image plane. The system enters apupil diameter of 280 mm, a field of view angle of 1×1°, a system focal length of 840 mm, and awavelength of 8 − 12 μmkm; the off-axis four-fold anti-structure is adopted. The optical mirror andstructural components of the material are Aluminum, the system’s own thermal radiation equivalent toa black-body temperature of 171 K. The equivalent black-body temperature of the system is measuredin a vacuum chamber. The temperature of the spacer is 100 – 120 K, the temperature of the coldplate is 85 – 87 K, and the integration time is 550 – 800 μs. At this time, the measured equivalentblack-body radiation temperature of the system is 172.9K; it is consistent with the simulation value.The design scheme solves the technical problems of low signal-to-noise ratio, poor image contrast, andshort detection distance of infrared laser communication system.