Achieving Transparency and Minimizing Loss of Rough Additively Manufactured Optical Components by a Dip-Coating Surface Finish

Additive manufacturing of optical, electrical and mechanical components is a beneficial approach for rapid prototyping of components and error elimination with short turn around times. However, additively manufactured components usually have rough surfaces which need post-processing, in particular for optical components where the surface roughness must be a small fraction of the wavelength. We demonstrate an innovative and economical approach by dip-coating with the same resin as used for printing, providing high transparency of the 3D-printed optical components and reduced surface roughness with perfect index matching of the coating layer in a simple post processing step. The surface roughness of the 3D-printed optical components drops to 5 nm (arithmetic average) after the dip-coating process. We observed significant performance enhancement after comparing the unprocessed optical components and dip-coated optical components, including achieving optical transparency and shiny surface finish of previously rough surfaces.