ИСТИНА

Nowadays, the industry has a need for the development of the technology of custom optical elements as part of prototyping or small-scale manufacturing. For example, such need arises, when it’s necessary to develop augmented reality glasses or photonic integrated circuits. An interesting additive approach to solving such problems is the use of projection microstereolithographiy 3D-printing (PμSL). The resolution of this approach can reach a few microns. At the same time, the printed samples have a layer-by-layer structure, that does not allow to achieve the optical quality of the surface. In order to solve this problem, authors developed post-processing technology which allowed to obtain smooth surface out. This approach has few drawbacks: 1) The fabricated optical elements cannot be used to work with high-intensity light due to the properties of existing photopolymers. 2) Existing photopolymers have low transparency in the UV range. For the fabrication of UV transparent structures with high chemical and temperature resistance, the technology of quartz 3D-printing has been developed, namely the one with a high aspect ratio including manufacturing of a composite photoresin, polymerization, and sintering in a vacuum furnace. High transmittance with wavelengths from 190 nm to 1100 nm for polymerized samples has been demonstrated. Lightguides with a diameter of 2 mm and length of 12 mm were obtained by 3D printing and the effect of total internal reflection was demonstrated Another interesting application of the above mentioned technology is the fabrication of custom active media in solid-state lasers. As seen in work of Moore et al [1], phase separation phenomena can be used to fabricate complex glass parts containing lanthanide salts and displaying light-controlled porosity. Thus, it is possible to change the concentration of rare-earth metals in glass in a scale of several microns, which can, for example, make it possible to fabricate laser arrays and other active media with unique properties. References: 1. Moore, D.G., Barbera, L., Masania, K. et al. Three-dimensional printing of multicomponent glasses using phase-separating resins. Nat. Mater. 19, 212–217 (2020).