Bioinspired energy-distribution-adjustable multi-focal-plane metalens for near-eye display with enhanced depth-of-field and resolution

The planar multi-focal-plane metalens (MFPM) consisting of subwavelength meta-atoms has immense potential for advancing near-eye displays by providing stereoscopic vision and compact optical solutions. However, panoramic deep imaging undoubtedly wastes resources. Strengthening the energy of a given MFPM’s focus in a targeted manner can enhance the depth-of-field (DoF) while refining information in the depth of interest, resulting in optimal resource allocation. Drawing inspiration from the multitiered retina of a jumping spider and the multi-point focusing capability of the human eye, we propose an energy-distribution-adjustable MFPM (EDA-MFPM) that can be designed by artificial intelligence. For demonstration, three EDA-MFPMs with energy distribution ratios of 0.5, 1, 2, and minimum size of 52 nm are fabricated by electron beam lithography. All EDA-MFPMs have a Strehl ratio greater than 0.9 and a resolution of 181 lp/mm or higher, and DoF is approximated to be 10 times that of a traditional metalens under the present experimental conditions and image-fusion method. As a proof of concept, a variable-focus augmented reality vision system utilizing the EDA-MFPMs, with two channels exhibiting a wide DoF and high-detail resolution for objects of interest is developed by adjusting the energy distribution ratios. These EDA-MFPMs are anticipated to promote the evolution of near-eye displays by enhancing light utilization through optimized energy distribution.