Investigation of stray radiation suppression in infrared imaging system using a novel broadband and high‐absorption ceramic coating

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‐absorptivity 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 devel-oped. 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 μm, 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.