Ultrafast laser processing of transparent materials for the fabrication of
biomimetic surfaces
V. Skoulas
1,2
, A. Papadopoulos
1,2
, G. D. Tsibidis
1
, E. Stratakis
1,2
1
Institute of Electronic Structure and Laser (IESL), Foundation for Research and
Technology Hellas (FORTH), N. Plastira 100, 70013, , Heraklion, Greece
Vassilika Vouton, 70013, Heraklion, Crete, Greece
2
Materials Science and Technology Department, University of Crete, 71003 Heraklion,
Greece
We report on the fabrication of laser induced periodical surfaces structures (LIPSS) on
transparent dielectric surfaces induced by inhomogeneous absorption of ultrashort laser
irradiation. The aim is to exploit the advantages of femtosecond pulsed laser technology in
producing controlled structures that mimic surfaces that already exist in nature or to modify
the optical properties of the irradiated material. Controlling surface morphology will be
potentially useful for potential application of dielectrics including precise optical elements
and anti-reflecting coatings.
Amorphous (a-SiO
2
) and crystalline (c-SiO
2
) fused silica substrates were irradiated with
femtosecond laser pulses and different polarization states. A systematic investigation was
carried out to correlate LIPSS periodicity dependence on the laser beam characteristics,
including photon energy, fluence, number of pulses and polarization state. The results
obtained indicate that the periodicity of LIPSS structures is highly dependent on the laser
parameters, while, their orientation is either parallel or perpendicular to the electric filed
polarization of the electric filed of the incident beam while mixed orientation has also been
observed.
A theoretical investigation was additionally conducted to explain the morphological
changes induced upon irradiation of fused silica with femtosecond pulses. The model
accounts for the the fundamental processes describing interaction of ultrashort laser pulses
with dielectric materials. The theoretical framework incorporates components related to all
possible laser-material intereaction phenomena, ranging from electron excitation to phase
transitions. It is shown that the model can sufficiently interpret the experimental observations
and adequately predicts both the LIPSS orientation and frequency.
Acknowledgement
The authors acknowledge
LiNaBiofluid
(Grant agreement No 665337) project for financial support.
References
1. Tsibidis G.D., Skoulas E., A.Papadopoulos, and Stratakis E., (2016), (
submitted
).
2. Tsibidis G.D., Skoulas E., and Stratakis E. (2015) ’Femtosecond laser micro-processing
with radially polarized beams’
Optics Letters
,
40
(22), 5172.
O 18
-53-
