Printable Nanoscopic Metamaterial Absorbers and Images with Diffraction-Limited Resolution

TL;DR

This paper presents a novel method for fabricating nanoscopic metamaterial absorbers with diffraction-limited resolution using electrohydrodynamic printing, enabling precise control of light absorption and high-resolution imaging.

Contribution

It introduces a rapid nanodripping technique for creating out-of-plane nanopillar forests with tunable optical properties at the diffraction limit.

Findings

Achieved ~95% broadband visible light absorption with minimal area coverage.

Demonstrated spatial control of grayscale imaging at 400 nm resolution.

Enabled tunable absorption from complete absorption to reflection by adjusting pillar height.

Abstract

The fabrication of functional metamaterials with extreme feature resolution finds a host of applications such as the broad area of surface/light interaction. Non-planar features of such structures can significantly enhance their performance and tunability, but their facile generation remains a challenge. Here, we show that carefully designed out-of-plane nanopillars made of metal-dielectric composites integrated in a metal-dielectric-nanocomposite configuration, can absorb broadband light very effectively. We further demonstrate that electrohydrodynamic printing in a rapid nanodripping mode, is able to generate precise out-of-plane forests of such composite nanopillars with deposition resolutions at the diffraction limit on flat and non-flat substrates. The nanocomposite nature of the printed material allows the fine-tuning of the overall visible light absorption from complete absorption to complete reflection by simply tuning the pillar height. Almost perfect absorption (~95%) over the entire visible spectrum is achieved by a nanopillar forest covering only 6% of the printed area. Adjusting the height of individual pillar groups by design, we demonstrate on-demand control of the gray scale of a micrograph with a spatial resolution of 400 nm. These results constitute a significant step forward in ultra-high resolution facile fabrication of out-of-plane nanostructures, important to a broad palette of light design applications. nanostructures, important to a broad palette of light design applications.