Reflective Metalenses for Near-Infrared Wavelengths Based on Silicon Nanorods

TL;DR

This paper designs a reflective metalens operating at 900 nm using silicon nanorods to achieve full phase control, enabling compact and efficient near-infrared optical focusing and manipulation.

Contribution

It introduces a novel silicon nanorod-based reflective metalens design optimized for near-infrared wavelengths, with detailed simulation-based phase and reflectance control.

Findings

Achieved full 2π phase control with silicon nanorods.

Optimized nanorod dimensions for enhanced focusing performance.

Demonstrated potential applications in imaging and optical communications.

Abstract

This paper presents the design and analysis of reflective metalenses optimized for a 900 nm wavelength, using silicon nanorods as the primary components. The metalens consists of unit cells, each containing a thin silicon rod. Lumerical FDTD software is used to create a detailed library that connects the dimensions of these nanorods with their respective phase shifts and reflectance properties. The nanorods are placed on a 70 nm thick silicon dioxide (SiO2) layer, with a 50 nm thick gold (Au) reflective layer underneath. In contrast to conventional transmissive metalenses, our design accomplishes complete 2{\pi} phase control via geometry-optimized silicon nanorods, facilitating compact reflective optics. By carefully examining the impact of nanorod dimensions on optical performance, the main goal is to optimize the metalens design for enhanced light focusing and manipulation, which could benefit imaging systems, optical communications, and sensor technology.