Near-zero-sidelobe optical subwavelength asymmetric focusing lens with dual-layer metasurfaces

TL;DR

This paper introduces a dual-layer dielectric metasurface lens capable of achieving asymmetric optical focusing with near-zero sidelobes at subwavelength scales, promising advancements in micro-nano optical applications.

Contribution

The paper presents a novel dual-layer dielectric metasurface design that enables simultaneous asymmetric focusing and near-zero sidelobe performance in optical frequencies.

Findings

Achieves broadband near-zero-sidelobe asymmetric focusing

Demonstrates effective subwavelength scale focusing

Potential applications in quantum communication and optical manipulation

Abstract

The existing metasurfaces with ultrathin volume for asymmetric transmission were often constructed by metal with low efficiency in optical frequency, and could not realize the optical asymmetric transmission and focusing simultaneously. Although the acoustic asymmetric focusing in asymmetric focusing lens (AFL) was realized, the obtained focal point was accompanied by large sidelobe. To solve those problems, an AFL with dual-layer metasurfaces designed by using dielectric materials can realize optical asymmetric transmission and focusing simultaneously in this paper. Furtherly, through optimizing the design theory of AFL, the near-zero-sidelobe (NZS) focusing can be realized on the subwavelength scale. The NZS asymmetric focusing of the optimized AFL is effective in broadband, which is expected to possess tremendous potential in the optical micro-nano processing, quantum communication, optical micromanipulation, etc.