  We report on the rst evidence of direct micropeak machining using a photonic
jet (PJ) with nanosecond laser pulses. PJ is a high concentrated propagative
light beam with a full width at half maximum (FWHM) smaller than the diraction
limit. In our case, PJs are generated with a shaped optical ber tip. Micropeaks
with a FWHM of around 1 $\mu$m, a height until 590 nm and an apex radius of 14
nm, were repeatability achieved on a silicon wafer. The experiments have been
carried out in ambient air using a 100/140 multimode silica ber with a shaped
tip along with a 35 kHz pulsed laser emitting 100 ns pulses at 1064 nm. This
study shows that the phenomenon occurs only at low energies, just under the
ablation threshold. Bulk material appears to have moved around to achieve the
peaks in a selforganized process. We hypothesize that the matter was melted and
not vaporized; hydrodynamic ow of molten material governed by surfacetension
forces may be the causes. This surface modication has many applications. For
example, this paper reports on the decrease of wettability of a textured
silicon wafer.
