Dynamic plasmonic structural color with deep sub-diffraction resolution based on borophene metasurfaces

Structural colors have seen rapid development in recent years, yet two-dimensional (2D) materials have seldom taken center stage as pixel materials. In this study, we propose a novel approach utilizing the emerging 2D material borophene, wherein resulting metasurfaces can generate plasmonic structural colors with tunability and ultra-high resolution. Numerical investigations demonstrate that borophene metasurfaces support visible localized surface plasmon resonances at deep subwavelength scales under linear-polarized light excitation, thus enabling the realization of structural colors with an unparalleled resolution of up to 10⁶ dots per inch (dpi)-an advancement of one order of magnitude over conventional counterparts. Furthermore, by modulating the electron density of borophene, these structural colors can be dynamically tuned across a broad spectrum. We highlight their high robustness against incident light angles and explore the influence of periodicity and polarization angle on color rendition. Finally, we present their potential applications in optical anti-counterfeiting, encryption, and switchable imaging methodologies. This work may promise future advancements in ultracompact, tunable, and lightweight display technologies.