Bilayer‐Metasurface Design, Fabrication, and Functionalization for Full‐Space Light Manipulation

Abstract Light manipulation with metasurfaces is usually implemented in either transmission or reflection space. Since the other half‐space is abandoned, it may hinder the improvement of information capacity and functionality of metasurfaces. Previously reported works have showcased some attempts to modulate trans‐reflective phase for full‐space light manipulation. However, they either fail to realize complete decoupling or introduce unwanted amplitude variation, which leads to the performance deterioration of meta‐devices. Herein, a general platform is proposed to independently manipulate the trans‐reflective light, benefitting from the significantly increased degrees of freedom gifted by bilayer metasurfaces. As examples, two different meta‐devices, i.e., a full‐space meta‐hologram and a trans‐reflective vortex beam generator both with pixel‐resolution up to 340 nm are fabricated and characterized. Owing to their completely decoupled trans‐reflective phase, full‐space light manipulation with total independence, low crosstalk, and high information capacity are well presented. This research can empower advanced research on optical storage, fiber communication, optical sensing, and lightening.