  We report on the studies of switching mechanism between normal and anomalous
laser induced periodic surface structures. We have shown that for high loss
metals the switching mechanism between normal and anomalous modes relays on an
interplay between two different feedbacks inherent into the structure formation
process: long range, low intensity dipole-like scattering of light along the
surface, which governs anomalous ripples parallel to the laser polarization,
and short range, high intensity plasmon-polariton wave, which is initiated by
near field dipole radiation and responsible for creation of ripples
perpendicular to the polarization, i. e. normal structure. By managing these
two feedbacks, we demonstrated creation of both normal and anomalous laser
induced periodic surface structures on the same surface. In contrast to the
previous studies, we have shown that the thermal oxidation mechanism can form
both normal and anomalous types of the structure, while the ablation mechanism
is involved only during the normal structure formation. Unlike the formation of
oxidation type anomalous structure, the formation of ablation type normal
structure does not have inherent negative feedback, which is self-regulating
nano-ripples formation. This feedback needs to be applied artificially, by
regulating scanning speed and pulse energy at a given repetition rate of the
laser. With implementation of nonlinear laser lithography technique for
ablation type of normal laser induced periodic surface structures we
demonstrated large area high regular nano-grating formation on different
surfaces with extremely high industrially acceptable speed.
