  We report on the morphological effects induced by the inhomogeneous
absorption of radially polarized femtosecond laser irradiation of nickel (Ni)
in sub-ablation conditions. A theoretical prediction of the morphology profile
is performed and the role of surface plasmon excitation in the production of
self-formed periodic ripples structures is evaluated. Results indicate a
smaller periodicity of the ripples profile compared to that attained under
linearly polarized irradiation conditions. A combined hydrodynamical and
thermoelastic model is presented in laser beam conditions that lead to material
melting. The simulation results are presented to be in good agreement with the
experimental findings. The ability to control the size of the morphological
changes via modulating the beam polarization may provide an additional route
for controlling and optimizing the outcome of laser micro-processing
