Subtractive Color Filters Based on a Silicon-Aluminum Hybrid-Nanodisk Metasurface Enabling Enhanced Color Purity.

Wenjing Yue,Sang-Shin Lee,Duk-Yong Choi,Eun-Soo Kim,Song Gao

doi:10.1038/srep29756

Wenjing Yue, Sang-Shin Lee + Show 3 more

Open Access

https://doi.org/10.1038/srep29756

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Abstract

Highly efficient subtractive tri-color filters of cyan, magenta, and yellow with enhanced color purity and robustness have been proposed and realized, by exploiting a silicon-aluminum (Si-Al) hybrid-nanodisk (ND) metasurface atop a Si substrate. The aspect ratio of the Si-Al hybrid ND is much lower than that of the conventional Si nanowire, which is disadvantageous due to its fragility and low color purity. In response to incident light impinging upon the metasurface, the hybrid-NDs individually play the role in exciting a magnetic dipole (MD) resonance through the mediation of Mie-scattering between the hybrid ND and air. The light stored in the resonance is coupled to the substrate, giving rise to a suppressed reflection. By virtue of the top Al ND, the excited MD resonance is strongly confined by the Si ND. As a consequence, a near-zero resonant dip that exhibits high off-resonance reflection and narrow bandwidth is produced for embodying highly efficient tri-color filters with enhanced color purity. The spectral position can be tuned by a simple adjustment of the hybrid-ND diameter. A full-color palette was successfully created with a high color purity and large color gamut. The proposed devices may be applied for photorealistic high-resolution color printing and holographic displays.

Highlights

From the perspective of the embodiment of a robust, ultrathin color filter, a lattice of Si nanodisks (NDs) featuring a low aspect ratio is categorically preferred to an array of elongated NWs
Each of the Si ND elements is deemed to support a Mie-scattering-mediated resonance in the form of the electrical dipole (ED) and the magnetic dipole (MD), which is effectively tuned by adjusting the ND diameter
We propose and demonstrate highly efficient structural subtractive tri-color filters of cyan, magenta, and yellow (CMY) that feature an enhanced color purity and robustness, taking advantage of a Si-Al hybrid-ND metasurface that is formed on a Si substrate

Summary

Introduction

From the perspective of the embodiment of a robust, ultrathin color filter, a lattice of Si nanodisks (NDs) featuring a low aspect ratio is categorically preferred to an array of elongated NWs. In contrast with the conventional materials with predetermined intrinsic properties, a Si-ND array, functioning as a dielectric metasurface, could be flexibly designed to deliver customized optical properties such as a negative refractive index and optical cloaking[20,21,22,23,24,25]. We propose and demonstrate highly efficient structural subtractive tri-color filters of cyan, magenta, and yellow (CMY) that feature an enhanced color purity and robustness, taking advantage of a Si-Al hybrid-ND metasurface that is formed on a Si substrate. A near-zero resonant reflection dip, which provides a high off-resonance reflection efficiency and a pertinent bandwidth, is obtained to embody the tri-color filters featuring the enhanced color purity. To verify the claimed performance in terms of the full-color generation, enhanced color purity, extended color gamut, and a high reflection, a full-color palette was successfully prepared by incorporating an array of filter elements with a span of ND diameters and periods

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Conclusion