###### Abstract  
Aiming at addressing the vulnerability of the infrared imaging opto-mechanical system to stray radiation interference caused by an external laser, a new method with a broadband and high-aspropritivity ceramic coating on the inner wall of the system is proposed to reduce the stray radiation intensity, which is helpful to improve the imaging quality of the detection image. Based on plasma electrolytic oxidation (PEO) technology, the preparation method and properties of a novel ceramic coating are studied, and a long-wave infrared imaging optical system with high-absorption ceramic coating is designed and developed. It is verified for the first time that the high-absorption ceramic coating can suppress the stray radiation in the infrared opto-mechanical system, and the effect of laser incident power and angle on the stray radiation is investigated. The experimental results show that the ceramic coating can achieve 95.4% high absorption in the wavelength range of 0.2-16 um, which can obviously suppress the stray radiation in the opto-mechanical system of infrared imaging caused by laser. The calculation of the stray radiation suppression ratio shows that, compared with the case without coating, the stray radiation intensity in the system can be reduced by 70% using the ceramic coating. stray radiation suppression; infrared imaging system; high-absorption ceramic coating; PEO 202120202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202020202022020202020202020202020202202020202020202020202020202202202020202020 light source in each irradiation area, resulting in different degrees of stray radiation at the image plane of the infrared detector. After multiple refraction and scattering, the stray light seriously affects the imaging quality and resolution of the infrared detection system. Therefore, the analysis and suppression of infrared stray radiation is very important to achieve high-precision infrared imaging detection. In order to quantitatively study the distribution of stray radiation, the simulation method is widely used to analyze the stray radiation in optical imaging systems [6; 7; 8; 9; 10]. Although there are many simulation methods to effectively predict and analyze the stray light of infrared imaging optical systems, the causes of stray radiation are very complex, which are related not only to the design, manufacturing process, and material characteristics of the infrared imaging system, but also to the aberration, target surface characteristics, and thermal radiation of system components. The analysis of stray radiation from the perspective of simulation often leads to some defects and differences between the actual infrared imaging system and the design model. Therefore, the actual measurement is also an essential link and an important reference for the evaluation of stray radiation in the infrared imaging system. According to the transmission theory of stray radiation, the basic methods for suppressing stray radiation are mainly divided into two kinds [11; 12; 13]: one involves controlling the direction of stray radiation energy transmission, which is realized by changing the path of light transmission, commonly by designing the physical structure of the lens and the shape of the light blocking ring to change the direction of beam transmission; the other involves achieving the attenuation of radiation energy by increasing the scattering times of stray radiation.