Reconstructing subwavelength resolution terahertz holographic images

Computer-generated holography typically generates terahertz (THz) holographic images with a pixel size larger than wavelength. We propose a multi-foci metalens model to reconstruct THz holographic images with subwavelength resolution. The designed devices are realized based on dielectric metasurfaces consisting of silicon micropillars with spatially variant orientations. By exploiting quasi-continuous profile of focal points as the pixels of a holographic image, a metalens can reconstruct a high-resolution target image on its focal plane. The effects of size and pitch of each sub-diffraction focal point on imaging quality and pixel resolution are discussed. The intensity distribution at each focal point indicates that the reconstructed images have subwavelength resolution. In comparison with conventional hologram designs, this design method can be used to reconstruct THz holographic images with subwavelength resolution, which have potential applications in THz communication, information security and anti-counterfeiting. (C) 2022 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement

Automated summary

In this study, a multi-foci metalens model was proposed to reconstruct THz holographic images with subwavelength resolution. The model, based on dielectric metasurfaces composed of silicon micropillars with spatially variant orientations, can generate high-resolution target images on its focal plane. The experimental results demonstrate that the reconstructed images have subwavelength resolution.