Emissivity enhancement method for blackbody coating based on femtosecond laser direct writing

High-performance blackbody sources, essential for infrared measurement systems, require coatings with high emissivity. However, conventional emissivity-enhancement methods face limitations, including weak adhesion and non-uniform directional emissivity. This paper proposes a novel method to overcome these limitations based on femtosecond laser direct writing (FsLDW). Experimental results show that the emissivity of the FsLDW-processed blackbody coating with a 5 μm period increases from 0.942 to 0.969 in the (3–14) μm band and from 0.957 to 0.986 in the (8–14) μm band. Moreover, this enhanced emissivity remains stable at temperatures up to 300°C, with fluctuations of less than 0.002 across a wide emission angle of ±50°.