Stitchless support-free 3D printing of free-form micromechanical structures with feature size on-demand

Abstract

Femtosecond laser based 3D nanolithography is a powerful tool for fabricating various functional micro- and nano-objects. In this work we present several advances needed to push it from the laboratory level use to the industrial production lines. First, linear stage and galvo-scanners synchronization is employed to produce stitch-free mm-sized structures. Furthermore, it is shown that by varying objective numerical apertures (NA) from 1.4 NA to 0.45 NA, voxel size can be tuned in the range from sub μm to tens of mm, resulting in structuring rates between 1809 μm3/s and 313312 μm3/s at 1 cm/s translation velocity achieved via simultaneous movement of linear stages and scanners. Discovered voxel/throughput scaling peculiarities show good agreement to ones acquired with numerical modeling. Furthermore, support-free 3D printing of complex structures is demonstrated. It is achieved by choosing pre-polymer that is in hard gel form during laser writing and acts as a dissolvable support during manufacturing. All of this is combined to fabricate micromechanical structures. First, 1:40 aspect ratio cantilever and 1.5 mm diameter single-helix spring capable of sustaining extreme deformations for prolonged movement times (up to 10000 deformation cycles) are shown. Then, free-movable highly articulated intertwined micromechanical spider and squids (overall size up to 10 mm) are printed and their movement is tested. The presented results are discussed in the broader sense, touching on the stitching/throughput dilemma and comparing it to the standard microstereolithography. It is shown where multiphoton polymerization can outpace standard stereolithography in terms of throughput while still maintaining superior resolution and higher degree of freedom in terms of printable geometries.

3D‐Printed high‐NA catadioptric thin lens for suppression of XPM background in Stimulated Raman Scattering microscopy

“…The additional losses could be mitigated by using newer photopolymers for the 3D printing (e.g., PO4 [28] ) that feature better absorption coefficient. Additionally, we expect that scattering from the proposed lens could be reduced by an improvement in the correction of the stitching between different printing areas, or adopting a stitch-less 3D printing system [26] . The scattering from the lens could also be reduced by an improved design of the outer rings in the reflective part of the lens.…”

“…"stitching" defects [26] that are generated by the stage backlash error and are visible as a hexagonal pattern in the SEM image of Figure2 .…”

Femtosecond Laser-Based Integration of Nano-Membranes into Organ-on-a-Chip Systems

“…We used the femtosecond laser "Carbide" (by Light Conversion), operating at the second harmonic (515 nm), with average power in the range from 0.1 to 10 mW, and a 250 fs pulse duration and repetition rate. More details on the setup can be found in [22]. Additionally, the technology is extremely adaptive for non-standard samples, such as channel systems, optical fibers, and even semiconductors.…”

“…This possibility also extends to PDMS channel systems prepared previously. Writing inside close channels is possible due to the imaging system integrated into the setup as well as the possibility to use different focusing objective lenses on demand [22]. In this particular work we tested 20 × 0.4 NA (1.5 mm focusing distance, Olympus, Tokyo, Japan) and 20 × 1.4 NA (0.32 mm focusing distance, Carl Zeiss AG, Jena, Germany) lenses.…”

“…In addition, multiphoton polymerization-based 3D laser lithography (3DLL) has shown huge potential in a wide array of applications [18][19][20][21]. The main advantage of this technology is the possibility to produce arbitrarily shaped 3D structures with feature size tuning from hundreds of nm to cm in the overall scale, i.e., the whole mesoscale [22]. It was also shown that structures can be produced on various functional substrates, like optical fibers or semiconductors [23,24].…”