All-Dielectric Dual-Color Pixel with Subwavelength Resolution.

An all-dielectric optical antenna supporting Mie resonances enables light confinement below the free-space diffraction limit. The Mie scattering wavelengths of the antenna depend on the structural geometry, which allows the antennas to be used for colored imprint images. However, there is still room for improving the spatial resolution, and new polarization-dependent color functionalities are highly desirable for realizing a wider color-tuning range. Here, we show all-dielectric color printing by means of dual-color pixels with a subwavelength-scale resolution. The simple nanostructures fabricated with monocrystalline silicon exhibit various brilliant reflection color by tuning the physical dimensions of each antenna. The designed nanostructures possess polarization-dependent properties that make it possible to create overlaid color images. The pixels will generate individual color even if operating as a single element, resulting in the achievement of subwavelength-resolution encoding without color mixing. This printing strategy could be used to further extend the degree of freedom in structural color design.