Ferrofluid‐Assisted Dynamic Metasurface 3D Holography Endowed With Rapid, Linear, and High‐Contrast Color Modulation.

Metasurface holography offers a highly promising approach for naked‐eye, full‐color, 3D displays. However, the natural static structure and material of the metasurface limit its ability to dynamically regulate the light field, posing a challenge for achieving photorealistic 3D holography. Here, a ferrofluid‐assisted dynamic metasurface is first demonstrated, conducting a 3D holography endowed with rapid, linear, and high‐contrast color modulation. The ferrofluid has nano‐structural control properties (flow behavior of nanoparticles and emulsion) that enable dynamic manipulation of the extinction (absorption and scattering) intensity in micron region across a broadband spectrum range (400–850 nm). By integrating the ferrofluid with a broadband metasurface, a novel dynamic meta‐hologram is created, which can not only regulate both amplitude and phase of the light field under a single wavelength laser but also in situ linearly changing the color of holographic images under multi‐wavelength lasers. This method provides a new perspective for implementing dynamic metasurface 3D holography capable of continuous color response. [ABSTRACT FROM AUTHOR]