3D printing of colored micro-optics

Commercially available optical photoresists for femtosecond direct laser writing are mostly transparent and only cover a small range of optical properties. This limits the design possibilities of micro-structures and micro-optics. Although the fabrication of 3D-printed micro-optics has become state of the art, the field of spectral filtering seems to be widely unexplored. In this work, we present, evaluate and compare different methods that can be used to fabricate colored micro-elements based on the already available polymers by adding pigments or dyes to the photoresists or by dyeing the fabricated structures in a post-printing process. Both optical performance and spectral filtering results are promising and could enable integrated color filtering or hyperspectral imaging in the field of 3D-printed micro-optics.