Diffraction and absorption of subpicosecond laser pulses by a spatially modulated surface

An analysis is made of the diffraction of ultrashort optical pulses by a surface with an arbitrary periodic relief allowing for strong interactions between the diffracted fields. The influence of the incident pulse profile and duration, and of the profile and depth of the surface relief on the excitation of electromagnetic surface waves and on the highest attainable local fields near a nonplanar interface is studied. The influence of these parameters on the deformation of the time envelope of the spectrally reflected signal, and also on the reflectivity and absorptivity of the surface is also examined. It is shown that the energy deposited in a target can be increased substantially if the surface is modulated.