Inverse-designed polarization-insensitive metasurface holography fabricated by nanoimprint lithography

Abstract

Metasurface holography, capable of fully engineering the wavefronts of light in an ultra-compact manner, has emerged as a promising route for vivid imaging, data storage, and information encryption. However, the primary manufacturing method for visible metasurface holography remains limited to the expensive and low-productivity electron-beam lithography (EBL). Here, we experimentally demonstrate the polarization-insensitive visible metasurface holography fabricated by high-throughput and low-cost nanoimprint lithography (NIL). The high-index titanium dioxide (TiO2) film is thinly deposited on the imprinted meta-atoms via atomic layer deposition (ALD) to achieve sufficient phase coverage. The calculated high-fidelity holograms are obtained by an inverse design method based on gradient-descent (GD) optimization. Under the various polarized light incidence, the correlation coefficients between the experimental reconstructed images and the target images all exceed 0.7 and the measured efficiencies are approximately 20%. The results demonstrate the high-precision, high-throughput, and cost-effective production of visible metaholograms, paving the way for the commercialization of meta-optics.