| Abstract |
Laser photopolymerization is one of the most used methods when fabrication of
3D-micro or nano- structures is required. However, conventional laser writing
techniques, especially when the fabrication of large area structures is needed, are very
time-consuming because of the point-by-point writing. In this thesis, multi-beam
interference is proposed as a simple and time-efficient method, able to accelerate the
production of complex structures by reducing the fabrication time up to two orders of
magnitude in comparison with the conventional point-by-point techniques.
Multi-beam interference as a well-established technique in the world of nonlinear
optics can create periodic structures according to the intensity distribution of the
interfering beams. Moreover, less or more complicated structures are realized as
phase or amplitude modulation occurs, leading to a diversity of possible motifs. On
these terms, this thesis is, also, investigating the possible patterns that are produced in
an interference process as well as the basic changes that are observed when
appropriate beam shaping is applied. The analysis focuses on the interaction between
two, three, four and five beams, and the shaping includes alteration of the distance
between the interfering beams and both phase and amplitude modulation.
Finally, we demonstrate the fabrication of complex periodic patterns that can be used
in biomedical applications or in catalysis, using the controlled multi-beam
interference technique. The samples can be fabricated in macroscopic dimensions and
in short processing times, opening thus potential market applications.
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Accelerating laser photopolymerization through beam shaping
