Fabrication of Fabry–Perot-cavity-based monolithic full-color filter arrays using a template-confined micro-reflow process

Transmissive color filters based on metal-dielectric-metal (MDM) Fabry–Perot (FP) resonators are of great interest for various applications due to their high stability, environmental friendliness and chemical inertia. However, it is still technically challenging to obtain a compact monolithic MDM-based color filter array (CFA) because of the difficulty in achieving microscale-pixelated stepwise dielectric films with designed thickness. In this work, we proposed a template-confined thermal reflow approach to fabricate monolithic CFA based on silver–polymethyl methacrylate–silver (Ag–PMMA–Ag) sandwich configuration. Via template-confined thermal reflow of periodic PMMA nanogratings with different filling density, the thickness of PMMA dielectric layer in each pixel can be independently controlled, enabling the spectral tunability across the whole visible light region with high transmission efficiency and narrow linewidth. Compared to conventional multiple deposition technique, the approach we proposed is able to control the thickness of dielectric film via a single exposure step and can be potentially applied in high-throughput production by combining nanoimprint lithography. (paper)