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°.