ANALYSIS OF LASER-ABSORPTION ON A ROUGH METAL-SURFACE

We have developed a simple model to estimate the cumulative absorption coefficient of an ultraviolet laser pulse impinging on a pure metal, including the effects of surface roughness whose scale is much larger than the laser wavelength lambda. The multiple reflections from the ro ugh surface may increase the absorption coefficient over a pristine, f lat surface by an order of magnitude. Thus, as much as 16% (at room te mperature) of the power of a 248 nm KrF excimer laser pulse may be abs orbed by an aluminum target. A comparison with experimental data is gi ven. (C) 1997 American Institute of Physics.