Spin and wavelength multiplexed nonlinear metasurface holography

TLDR

Metasurfaces are ultrathin metamaterials that can precisely control phase, amplitude, and polarization of light; geometric metasurfaces encode a Pancharatnam–Berry phase through meta‑atom orientation, providing robust, dispersionless wave manipulation and enabling holography with continuous phase control that surpasses conventional depth‑controlled holography. The study aims to demonstrate spin and wavelength multiplexed nonlinear metasurface holography, enabling the construction of multiple target holographic images carried independently by fundamental and harmonic generation waves of different spins. The authors achieve this by employing geometric phase encoding of meta‑atom orientation to generate independent holographic images in both fundamental and harmonic waves, thereby creating nondispersive, crosstalk‑free post‑selective channels. The resulting nonlinear holograms offer independent, nondispersive, and crosstalk‑free post‑selective channels suitable for holographic multiplexing, multidimensional optical data storage, anti‑counterfeiting, and optical encryption.

Abstract

Abstract Metasurfaces, as the ultrathin version of metamaterials, have caught growing attention due to their superior capability in controlling the phase, amplitude and polarization states of light. Among various types of metasurfaces, geometric metasurface that encodes a geometric or Pancharatnam–Berry phase into the orientation angle of the constituent meta-atoms has shown great potential in controlling light in both linear and nonlinear optical regimes. The robust and dispersionless nature of the geometric phase simplifies the wave manipulation tremendously. Benefitting from the continuous phase control, metasurface holography has exhibited advantages over conventional depth controlled holography with discretized phase levels. Here we report on spin and wavelength multiplexed nonlinear metasurface holography, which allows construction of multiple target holographic images carried independently by the fundamental and harmonic generation waves of different spins. The nonlinear holograms provide independent, nondispersive and crosstalk-free post-selective channels for holographic multiplexing and multidimensional optical data storages, anti-counterfeiting, and optical encryption.