High-quality, intricate glass shapes, like tiny pretzels or castles, can be manufactured using standard 3D printing technology, reports a study in Nature this week. The technique can produce structures of high optical quality that may be suitable for the design of complex lenses and filters.

Glass has a number of useful properties, including electrical and thermal insulation, and unmatched optical transparency. Creating bespoke structures, especially from high-purity glasses such as fused silica glass, is difficult owing to the need for high processing temperatures and/or harsh chemicals. The new technique, devised by Bastian Rapp and colleagues, overcomes this issue by using a free-flowing silica nanocomposite called ‘liquid glass’ in a standard 3D printer to produce complex shapes that are then heat-treated to produce optical-quality, fused silica glass structures. These structures are smooth, transparent, and have features as small as a few tens of micrometres.

The new technique produces surfaces with sufficient clarity and reflectivity for a range of optical applications. The process also helps to make one of the oldest known materials accessible to twenty-first-century 3D printing techniques, the authors conclude.