Influence of buffer layer on adhesion of 1 064 nm, 532 nm frequency-doubled antireflection coating to LBO crystal

1 064 nm, 532 nm frequency-doubled antireflection coatings with no buffer layer or with different buffer layers were fabricated on LBO crystal using electron beam evaporation technique. The optical property, adhesion and laser-induced damage threshold(LIDT) were investigated. The results showed that the reflectance of all samples was below 0.1% and 0.2% at wavelength of 1 064 nm and 532 nm, respectively. Compared with the sample with no buffer layer, the critical adhesion of the sample with Al2O3 buffer layer of was increased by 43.1% and that of the coating with SiO2 buffer layer of was improved significantly, and the critical adhesion of the coating with MgF2 buffer layer of was decreased. The mechanism of adhesion strengthening of the coating was analyzed by full plastic indentation and