Bond-Selective Intensity Diffraction Tomography

TL;DR

This paper introduces Bond-selective Intensity Diffraction Tomography (BS-IDT), a low-cost, rapid 3D chemical imaging technique that recovers infrared spectra and bond-specific refractive index maps from intensity data.

Contribution

It presents a novel computational mid-infrared photothermal microscope capable of high-resolution, bond-selective 3D imaging using a simple brightfield setup with an add-on pulsed light source.

Findings

Successfully extracts high-fidelity infrared fingerprint spectra.

Achieves volumetric chemical imaging of biological cells in ~20 seconds per volume.

Demonstrates quantitative lipid analysis in cancer cells and imaging of C. elegans.

Abstract

Recovering molecular information remains a grand challenge in the widely used holographic and computational imaging technologies. To address this challenge, we developed a computational mid-infrared photothermal microscope, termed Bond-selective Intensity Diffraction Tomography (BS-IDT). Based on a low-cost brightfield microscope with an add-on pulsed light source, BS-IDT recovers both infrared spectra and bond-selective 3D refractive index maps from intensity-only measurements. High-fidelity infrared fingerprint spectra extraction is validated. Volumetric chemical imaging of biological cells is demonstrated at a speed of ~20 seconds per volume, with a lateral and axial resolution of ~350 nm and ~1.1 micron, respectively. BS-IDT's application potential is investigated by chemically quantifying lipids stored in cancer cells and volumetric chemical imaging on Caenorhabditis elegans with a large field of view (~100 micron X 100 micron).