Printing, characterising, and assessing transparent 3D printed lenses for optical imaging

The production of high-quality lenses for optical instrumentation has involved subtractive manufacturing methods for centuries. These methods have demanded specialist equipment and expertise that often render custom high-grade bulk glass optics inaccessible. We aimed to develop a low-cost, accessible, and reproducible method using consumer-grade technology to manufacture high-quality three-dimensional (3D) printed lenses with comparable performance to glass lenses. Various 3D printed planoconvex lenses were produced using a consumer grade 3D printer and low-cost spin coating setup, and printed lenses were compared to their commercial glass counterparts. A range of mechanical and optical methods are introduced to determine the surface curvature of 3D printed lenses, providing a wide range of quality control methods. Amongst others, high-resolution interference reflection microscopy methods were used to reconstruct the convex surface of printed lenses and quantify their radius of curvature. Moreover, the optical throughput and focusing performance of 3D printed lenses were assessed using optical transmissivity measurements and classical beam characterisation methods. We determined that all 3D printed lens prescriptions tested had comparable surface curvature and optical performance to commercial glass lenses. Finally, we demonstrated the application of 3D printed lenses for brightfield transmission microscopy, resolving sub-cellular structures over a 2.3 mm field of view. The high reproducibility and comparable performance of 3D printed lenses present a great opportunity for additive manufacturing in the production of bespoke optical elements for low-cost rapid prototyping and improved accessibility to high-quality optics in low-resource settings.