  Laser induced periodic surface structures (LIPSS) are formed by multiple
irradiation of femtosecond laser on a silicon target. In this paper, we focus
and discuss the surface plasmon polariton mechanism by an analysis of transient
phase-matching conditions in Si on the basis of a single pulse experiment and
numerical simulations. Two regimes of ripple formation mechanisms at low number
of shots are identified and detailed. Correlation of numerical and experimental
results is good.
