Additive manufacturing of lightweight mirrors (Conference Presentation)

Additive manufacturing offers new routes to lightweight optics inaccessible by conventional methods by providing a broader range of reconciled functionality, form factor, and cost. Predictive lattice design combined with the ability to 3D print complex structures allows for the creation of low-density metamaterials with high global and local stiffness and tunable response to static and dynamic loading. This capacity provides a path to fabrication of lightweight optical supports with tuned geometries and mechanical properties. Our approach involves the simulation and optimization of lightweight lattices for anticipated stresses due to polishing and mounting loads via adaptive mesh refinement. The designed lattices are 3D printed using large area projection microstereolithography (LAPuSL), coated with a metallic plating to improve mechanical properties, and bonded to a thin (1.25 mm) fused silica substrate. We demonstrate that this lightweight assembly can be polished to a desired flatness using convergent polishing, and subsequently treated with a reflective coating. *This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344 within the LDRD program. LLNL-ABS-738806.