Better understanding of the effect of radiation on defectivity is essential to improve the stability of Ru-capped MoSi multilayer blanks. In this work, the effect of radiation exposure on the surface adhesion properties of Ru-capped MoSi multilayers was studied using optical radiation (172 nm, 532 nm, and 1064 nm). Regardless of wavelength, the surface adhesion of defects increases when exposed to radiation and scales with laser power. Changes in adhesion are compared to surface roughness. For different wavelengths, chemical modification of the surface and optical absorption of defects exhibit different contributions.