Ceramics play an important role in today’s science and industry as it can withstand immense thermal, mechanical, chemical and other hazards. In recent years, the interest in 3D printing micro- or even nano-structures out of ceramics has been growing rapidly. Therefore, direct laser writing by two photon polymerization together with calcination have been proved to be a powerful tool for the fabrication of fully 3D glass-ceramic objects in micro- and nano-scale . However, producing such structures with unique properties at meso scale (features from nm to cm overall size) is one of the greatest challenges . In order to overcome it the composition of the starting materials and as well as conditions of calcination have to be fully understood and enhanced.
We synthesized a series of organic-inorganic polymer precursors via sol-gel method varying the molar ratio of silicon (Si) and zirconium (Zr) complexes (Si:Zr, where Si=9; 8; 7; 6; 5 and Zr=1; 2; 3; 4; 5)  and investigated 3D processing of these materials. The study shows that the “glassy” phase structures retain their shape without any distortion. Furthermore, calcination provides a route for the continuous size control and formation of a variety of phase transformation for free-form nano-/micro-objects. It is shown that due to the isotropic nature of the shrinkage during calcination fabricated 3D objects retain complex geometry. Nano-woodpiles, bulk-woodpile hybrids and full bulk structures are formed. The sizes of single features in these objects vary from 120 nm to 800 nm with overall size going to 30 µm. Finally, changes in focused ion beam machining rates between standard and calcinated materials are shown proving enhanced resiliency of the final product (up to 50%).
 Gailevičius, D., et al., Additive-manufacturing of 3D glass-ceramics down to nanoscale resolution. Nanoscale Horiz.;
4, 647-651; (2019)
 L. Jonusauskas, D. Gailevicius, S. Rekstyte, T. Baldacchini, S. Juodkazis, M. Malinauskas, Mesoscale Laser 3D Printing, Opt. Express
27 (11), 15205-15221 (2019)
 Ovsianikov, A., et al., Ultra-Low Shrinkage Hybrid Photosensitive Material for Two-Photon Polymerization Microfabrication. ACS Nano; 2(11), 2257-2262; (2008)
Ultrafast laser lithography allows additive fabrication of 3D sub-micrometric size objects in various materials. Here we demonstrate significant new capabilities achievable with this approach by using hybrid organic–inorganic material as the initial medium for laser structuring, and adding a high-temperature post-fabrication treatment. Calcination at temperatures of up to 1500°C leads to decomposition of the organic component in the initial material, and sintering of the inorganic component into a stable matrix. This results in the final object composed purely of glass-ceramic material, and having volume and size significantly reduced in comparison to those of the initial object. Possibilities to control both the composition and degree of the thermal down-scaling will be demonstrated. The proposed new pathway to inorganic 3D nanoscale objects and structures is easy to implement, and allows one to significantly surpass the spatial resolution and feature size achievable using laser lithography only. We study optical properties of transparent inorganic microstructures and optimize them for specific photonic functions. In the future it may be useful in space and defense-related areas for realization of chemically and thermally resilient photonic components, such as narrow-band IR emitters and optical sensors to be used in nuclear power plants and other harsh environments.
D. Gailevicius, V. Padolskyte, L. Mikoliunaite, S. Sakirzanovas, S. Juodkazis, and M. Malinauskas, ”Additive-Manufacturing of 3D Glass-Ceramics down to Nanoscale Resolution,” Nanoscale Horiz., 10.1039/C8NH00293B (2019), online first.