Planar Wide-Angle Imaging System with a Single-Layer SiC Metalens

TL;DR

A new flat lens made of silicon carbide enables wide-angle imaging in a compact design, useful for medical and sensing applications.

Contribution

A single-layer SiC metalens with a 90° field of view is demonstrated using a novel gradient-based optimization method.

Findings

A single-layer SiC metalens with a 90° field of view was successfully fabricated and tested.

The GOPP optimization method enabled off-axis aberration control in a planar structure.

The metalens operates at 803 nm with a focal length of 1 mm and achieved effective wide-angle imaging.

Abstract

Optical systems with wide field-of-view (FOV) imaging capabilities are crucial for applications ranging from biomedical diagnostics to remote sensing, yet conventional wide-angle optics face integration challenges in compact platforms. Here, we present the design and experimental demonstration of a single-layer silicon carbide (SiC) metalens achieving a 90° total FOV, whose planar structure and small footprint address the challenges. This design is driven by a gradient-based numerical optimization strategy, Gradient-Optimized Phase Profile Shaping (GOPP), which optimizes the phase profile to accommodate the angle-dependent requirements. Combined with a front aperture, the GOPP-generated phase profile enables off-axis aberration control within a planar structure. Operating at 803 nm with a focal length of 1 mm (NA = 0.25), the fabricated metalens demonstrated focusing capabilities across the wide FOV, enabling effective wide-angle imaging. This work demonstrates the feasibility of using numerical optimization to realize single-layer metalens with challenging wide FOV capabilities, offering a promising route towards highly compact imagers for applications such as endoscopy and dermoscopy.

Figures