Wide field-of-view and large depth-of-field metalenses

TL;DR

This paper introduces two compact metalenses that achieve wide field-of-view, extended depth-of-field, and high resolution in a tiny footprint, enabling advanced endoscopic and microscopic imaging with computational image reconstruction.

Contribution

The work presents novel metalens designs that combine wide FOV, large DOF, and high resolution in a miniaturized form factor, surpassing traditional microendoscope limitations.

Findings

Achieved 172° FOV with metalenses

Extended DOF from 0.4 mm to over 300 mm

Resolved 30 line pairs per millimeter

Abstract

The ability to visualize both macroscopic and microscopic features over an extended field of view is essential for endoscopic imaging and other applications ranging from machine vision to microscopy. However, miniaturizing endoscopes introduces inherent trade-offs between size and optical performance, including field-of-view (FOV), depth-of-field (DOF), and resolution. These constraints limit the use of microendoscopes in clinical settings such as early cancer detection within narrow, hard-to-access anatomical regions, including the lung, ovaries, and pancreas. State-of-the-art microendoscopes typically rely on microlens assemblies that increase both cost and size. Their large f-numbers also hinder the collection of high-resolution information from live tissue. In this work, we present two compact metalens designs that provide wide FOV, extended DOF, and high resolution, enabled by custom-tailored point spread functions (PSFs). The devices achieve a full 172 degrees FOV, an extended DOF from 0.4 mm to beyond 300 mm, and a resolution of 30 line pairs per millimeter, all within a 1 mm x 1 mm x 0.2 mm footprint. A key advantage of our approach is the ability to transition seamlessly between low and high magnification without mechanical refocusing. Final images are reconstructed through backend deconvolution, highlighting the potential of hybrid imaging systems that integrate computational techniques with flat-optics components.