Twin-Image Free Multichannel Vectorial Holography With Nonlinear Chiroptical Metasurfaces

Multichannel vectorial holography has essential applications in the fields of optical information processing and optical communications. With the development of metasurface devices, multiple vortex beams and holographic images with vectorial polarization distributions have been demonstrated in both linear and nonlinear optical regimes. However, most of the metasurface-based vectorial holography experiences twin-image problem, affecting the polarization contrast, image quality, and so on. Here, we demonstrate the twin-image free multichannel vectorial holography with nonlinear chiroptical metasurfaces, which consist of pairs of enantiomeric meta-atoms. Such meta-atoms provide two independent channels that rely on the giant circular dichroism effect in second harmonic generation processes for manipulating the amplitude and phase of the nonlinear optical waves. By combining the concept of nonlinear geometric phase and the Gerchberg–Saxton algorithm, the twin-image free multichannel vectorial vortex beams and holographic images are realized. The proposed nonlinear chiroptical metasurface platform may open new routes to develop ultracompact and multifunctional devices for high-capacity optical information processing and data storage.