Synthesis of Photonic Crystal Thin Films with Low Glossiness for Thermal Stealth

A novel type of photonic crystal thin film with low glossiness was designed and synthesized by electron beam evaporation to reduce its saliency under visible light detection.First,the influence of the various factors,including the substrate roughness,average reflectivity in visible bands,deposition rate and temperature,on the glossiness was investigated for design optimization of photonic crystal films.Next,the well-designed photonic crystal films were deposited under the optimized conditions.Finally,the microstructures and thermal stealth behavior of the photonic crystal coatings were characterized with scanning electron microscopy and mid/far infra-red thermal imager.The results show that the new photonic crystal coatings with a surface glossiness of ~4.2 GU,had the average emissivity of 0.2(0.25) in 3~5 μm(8~14 μm) band,showing good thermal stealth performance against mid/far infrared irradiation.