Glass is increasingly desired as a material for manufacturing complex microscopic geometries, from the micro-optics in compact consumer products to microfluidic systems for chemical synthesis and biological analyses. As the size, geometric, surface roughness, and mechanical strength requirements of glass evolve, conventional processing methods are challenged. We introduce microscale computed axial lithography (micro-CAL) of fused silica components, by tomographically illuminating a photopolymer-silica nanocomposite that is then sintered. We fabricated three-dimensional microfluidics with internal diameters of 150 micrometers, free-form micro-optical elements with a surface roughness of 6 nanometers, and complex high-strength trusses and lattice structures with minimum feature sizes of 50 micrometers. As a high-speed, layer-free digital light manufacturing process, micro-CAL can process nanocomposites with high solids content and high geometric freedom, enabling new device structures and applications.
Computed axial lithography, when used in polymeric systems, directly solidifies freeform three-dimensional geometries inside liquid or gelled materials. Currently, this patterning system operates in open loop where projections are designed prior to the print so identification of errors and corrections can only be done after the printed object has been processed. This work introduces an in-situ 3D refractive index monitoring system to track localized material conversion by performing tomographic reconstruction from color Schlieren images. Our system successfully reconstructed evolving phase objects inside resins and the reconstruction quality was verified by comparison with isosurface laser scans. The technique provides support for physics-based real-time pattern modification to improve print fidelity and reduce manual iteration time when experimenting with new materials. CCS CONCEPTS • Hardware; • Emerging technologies; • Emerging optical and photonic technologies;
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