Broadband long-range thermal imaging via meta-correctors

TL;DR

This paper presents a hybrid optical system combining refractive lenses and silicon meta-correctors to achieve high-quality, broadband long-range thermal imaging, significantly improving contrast and image clarity at 250 meters.

Contribution

The work introduces a novel hybrid system with meta-correctors that correct chromatic aberrations in LWIR imaging, enabling lightweight, cost-effective long-range thermal imaging.

Findings

Three-fold contrast enhancement over refractive-only systems

Clear recognition of human features at 250 meters

Uses off-the-shelf components without germanium

Abstract

Long-range imaging in the thermal infrared band is critical for applications such as environmental monitoring, industrial inspections, and surveillance. To achieve high quality imaging, these systems typically require large apertures and many elements with complex shapes to correct aberrations, adding significant weight and cost. Large-area metasurface optics offer a promising solution for weight reduction; however, their substantial chromatic aberrations limit their effectiveness in the long-wave infrared (LWIR) band where broadband imaging is typically desired. In this work, we introduce a hybrid system comprising four refractive lenses and two all-silicon metasurface correctors (meta-correctors) to achieve high-quality, broadband thermal imaging at long range. Compared to a refractive-only assembly, our system demonstrates a three-fold contrast enhancement at the detector's half-Nyquist frequency. Testing outside the laboratory reveals noticeably sharper images, with human features clearly recognizable at distances of 250 meters. The assembly utilizes off-the-shelf refractive elements and avoids the use of germanium, which poses a supply chain risk. Our findings highlight the potential of hybrid meta-corrector systems to enable long-range, lightweight, and cost-effective LWIR imaging solutions.