Highly reflective subtractive color filters capitalizing on a silicon metasurface integrated with nanostructured aluminum mirrors

Metasurface-based color filters have been recently applied for the creation of imaging devices and color printing in a subwavelength scale. In this work, a highly reflective subtractive color filter featuring an excellent color contrast is conceived and demonstrated, by exploiting a crystalline-silicon nanopillar (NP)-based dielectric metasurface integrated with an aluminum disk mirror (DM) and holey mirror (HM) at the top and bottom, respectively. A deep suppression in reflection is acquired through a magnetic dipole (MD) resonance that is supported by the constituent NP, and can be effectively tailored via the control of the NP diameter. The cooperation of the nanostructured DM and HM plays a dual role of dramatically boosting the efficiency and reinforcing the confinement of the MD in the NP, which is primarily accountable for the reduction in the spectral bandwidth. For the manufactured filters, both a high reflection efficiency reaching ∼70% and relatively small bandwidth of ∼55 nm are attained, thus leading to a broad palette of vivid and bright colors. The proposed devices are supposed to exhibit a polarization-insensitive operation and a relaxed angular tolerance, thereby facilitating the implementation of miniaturized display/imaging devices with a high resolution and excellent color fidelity. (Figure presented.).