Abstract: The use of two-photon absorption (TPA) for polymerization,
also known as 3D Lithography, Direct Laser Writing, or High-Precision 3D Printing is gaining increasing attraction
in industrial fabrication of micro- and nanostructures. Mainly due to its vast freedom in design and high-resolution capabilities,
TPA enables the fabrication of designs which are not feasible or far too complicated to be achieved with
conventional fabrication methods. TPA is a scanning technology and fabrication in 3D requires axial overwritings. High
industrial throughput fabrication can be achieved by intelligent fabrication strategies combined with an excellent material
basis. Further boosting the throughput can be achieved by multispot exposure
strategies. In this paper, massive parallelization is demonstrated which was realized
by using a beam splitting diffractive optical element (DOE). Simultaneous fabrication
using commercially available acrylate-based hybrid resin with 121 parallel focal spots arranged as 11 x 11 array is
reported. Structures fabricated by a single laser beam and by 121 parallel beams are compared to each other with regard to
shape and polymerization threshold. It was found that polymerization is strongly increased when parallel beams are
used, especially for the central beams. As a result, polymerization threshold is lower in the center of the 11 x
11 array compared to the edges of the array. Furthermore, structures at the center of the 11 x 11 array are bigger
compared to structures at the edges of the array when assigning equal intensity to all diffracted beams. These results are
attributed to diffusion of photo initiators, quenchers, and radicals.
Copyright 2020 Society of
Photo-Optical Instrumentation Engineers. One print or electronic copy may be
made for personal use only. Systematic reproduction and distribution,
duplication of any material in this paper for a fee or for commercial purposes,
or modification of the content of the paper are prohibited.
Publisher/link to publication: Proc. SPIE 11271, Laser 3D Manufacturing VII https://dx.doi.org/10.1117/12.2545788
Open
Access: https://multiphoton.de/references/
