Independent Multichannel Wavefront Modulation for Angle Multiplexed Meta-Holograms

Meta-holograms have been investigated widely because of their capabilities that are not feasible in conventional holograms, such as full-color, broadband, and bifacial image generation performance. In particular, a high degree of freedom in designing meta-atoms provides opportunities to multiplex holograms by using light properties, such as angle, polarization, and wavelength. However, further development of techniques for meta-holograms recording multiple wavefronts is still necessary to expand the amount of optical information and improve the security level of holographic encryption. In this study, detour phase holograms are combined with the spatial multiplexing method to record four phase profiles in a single metasurface device. Independent wavefront modulation, which can process four channels as a bijective function, is realized by engineering the scattering properties of the meta-atom. Based on the concept, meta-holograms are demonstrated experimentally, independently generating four different images depending on the incident angles with high fidelity. Because of the expanded capacity and independence, the proposed device provides a potential platform for optical devices in various fields, such as holography, multifunctional flat optics, and off-axis optical devices.

Automated summary

Meta-holograms offer capabilities not feasible in conventional holograms, such as full-color, broadband, and bifacial image generation performance. By combining detour phase holograms with spatial multiplexing, four phase profiles can be recorded on a single device, expanding the optical information. The independent wavefront modulation achieved by engineering the scattering properties of the meta-atom allows for generating four different images with high fidelity, showcasing potential applications in holography, multifunctional flat optics, and off-axis optical devices.