Metasurfaces for infrared multi-modal microscopy: phase contrast and bright field

TL;DR

This paper demonstrates a silicon-based metasurface capable of performing both phase contrast and bright field microscopy in the near-infrared, enabling multi-modal imaging with a single device and tunable by polarization.

Contribution

The work introduces a novel metasurface that combines phase contrast and bright field microscopy into one tunable, miniaturized device for infrared imaging.

Findings

Successfully imaged C. elegans, cancer cells, and tissue samples.

Achieved tunable multi-modal imaging by polarization control.

Potential for label-free, point-of-care diagnostics.

Abstract

Different imaging modalities are used to extract the diverse information carried in an optical field. Two prominent modalities include bright field and phase contrast microscopy that can visualize the amplitude and phase features of a sample, respectively. However, capturing both of these images on the same camera typically requires interchanging optical components. Metasurfaces are ultra-thin nanostructures that can merge both of these operations into a single miniaturized device. Here, a silicon-based metasurface that supports a Mie resonance is demonstrated to perform near-infrared phase contrast and bright field multi-modal microscopy that can be tuned by changing the polarization of the illumination. We performed experiments using optical fields with phase variations synthesized by a spatial light modulator and introduced by propagation through semi-transparent samples, including C. elegans, unstained human prostate cancer cells and breast tissue. The results demonstrate the potential of metasurfaces for label-free point-of-care testing.