  We report on a new, single-step and scalable method to fabricate highly
ordered, multi-directional and complex surface structures that mimic the unique
morphological features of certain species found in nature. Biomimetic surface
structuring was realized by exploiting the unique and versatile angular profile
and the electric field symmetry of cylindrical vector (CV) femtosecond (fs)
laser beams. It is shown that, highly controllable, periodic structures
exhibiting sizes at nano-, micro- and dual-scale micro and nano scales can be
directly written on Ni upon line and large area scanning with radial and
azimuthal polarization beams. Depending on the irradiation conditions, new
complex multi-directional nanostructures, inspired by the Shark skin
morphology, as well as superhydrophobic dual-scale structures mimicking the
Lotus leaf water repellent properties can be attained. It is concluded that the
versatility and features variations of structures formed upon scanning with CV
beams is by far superior to those obtained via laser processing with linearly
polarized beams. More important, by exploiting the capabilities offered by fs
CV optical fields, the present technique can be further extended to fabricate
even more complex and unconventional structures. We believe that our approach
provides a new concept in laser processing of materials, which can be further
exploited for expanding the breadth and novelty of potential applications.
