[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Stitchless Support-Free Fabrication of Free-Form Micromechanical Structures using Femtosecond Laser 3D Lithography

摘要： Femtosecond laser based 3D nanolithography is gaining popularity in huge variety of fields. However, further improvements are needed to push it from laboratory level use into a wide spread adaptation. These include increasing fabrication throughput without sacrificing quality of a final product and making the most challenging, free-movable 3D structures easy to print. In this work we present several advances needed to achieve these goals. First, linear stage and galvo-scanners synchronization is employed to produce stitch-free mm-sized structures with features down to micrometers. Furthermore, resolution bridge method is used to determine feature sizes acquired by varying objective numerical apertures (NA) from 0.8 NA to 1.4 NA. This way voxel size can be tuned in the range from 330 nm to 1.7 μm in transverse and 1.9 μm to 7.9 μm in longitudinal directions. At 1 cm/s translation velocity it results in voxel volumes from 0.017 μm3 to 3.759 μm3 with structuring rates at 2426 μm3/s and 104767 μm3/s respectively. This two orders of magnitude tunability is exploited to fabricate various functional structures. For instance, deformable microcantilevers and microsprings capable of sustaining multiple deformation cycles were created using 0.8 NA objective chosen for faster printing with acceptable resolution. Performance and longevity of these elements were characterized in both qualitative and quantitative manner. Furthermore, the hard gel form of the SZ2080 photopolymer used in this work allowed to perform support-free structuring of free-movable micromechanical components employing high-resolution structuring achievable with 1.4 NA objective. Possibility to forgo usage of supports needed with liquid resins eliminates the need to remove supports after printing making the whole process simpler. To demonstrate the potency of this approach movable mm-sized micromechanical spider and squid were fabricated, showing possibility to print true 3D hinge-like microstructures (feature size down to micrometers). Such structures have huge potential in the fields of sensors and microrobotics as mechanically induced deformation of movement can be employed as either means to detect outside force or provide a basis for self-propelling functional structures.