Design of double-wavelength reflective multi-layer coatings for laser protection

The optical performances of reflective multi-layers coatings were analyzed in theory by using the software of TF-Calc. The factors which affect the optical performances of the coatings, such as the structure of the coatings, the parity of the number of the layers, and the material of the first plated layer, were analyzed. A 1-2 type multi-layer reflective coatings with ZrO₂ and SiO₂ as its coating material and PC as its substance was designed to reflect the lasers whose wavelengths were 532 nm and 1064 nm, respectively. The results showed that the theoretic transmittances at 532 nm and 1064 nm were 0.01% (the optical density D=4). A 1:5 type 23 layers reflective coating was plated on PC to validate the theoretic design. Its optical performance at the wavelength of 400 nm-1200 nm was tested, and the results almost agreed with the theoretical value.