Infrared holographic image projection by all-dielectric metasurfaces

All-dielectric metasurfaces can project an arbitrary holographic image via geometrical phase control of incident light. We investigated Si-based holographic metasurfaces for infrared holography. The holographic metasurface consists of various-sized pillars formed in a flat Si wafer. The configuration of the pillars was determined according to the required phase diagram for the target image. Numerical calculations demonstrated that the holographic image was obtained in the long-wavelength infrared region. The proposed metasurfaces can be used in a wide range of applications, including thermal control devices, thermal identification, and security.