Correlative infrared optical coherence tomography and hyperspectral chemical imaging

TL;DR

This paper presents a dual-band optical coherence tomography system combined with mid-infrared hyperspectral imaging, enabling non-destructive, correlative morphological and chemical analysis of complex materials.

Contribution

It introduces a cost-effective, integrated OCT and MIR spectroscopy system with a single supercontinuum laser source for in-situ multidimensional material characterization.

Findings

Successfully demonstrated correlative morphological and chemical imaging.

Achieved high-resolution 3D imaging of multi-layered ceramic-polymer specimens.

Enabled sensitive chemical analysis in previously inaccessible spectral regions.

Abstract

Optical coherence tomography (OCT) is a high-resolution three-dimensional imaging technique that enables non-destructive measurements of surface and subsurface microstructures. Recent developments of OCT operating in the mid-infrared (MIR) range (around 4 {\mu}m) lifted fundamental scattering limitations and initiated applied material research in formerly inaccessible fields. The MIR spectral region, however, is also of great interest for spectroscopy and hyperspectral imaging, which allow highly selective and sensitive chemical studies of materials. In this contribution, we introduce an OCT system (dual-band, central wavelengths of 2 {\mu}m m and 4 {\mu}m) combined with MIR spectroscopy that is implemented as a raster scanning chemical imaging modality. The fully-integrated and cost-effective optical instrument is based on a single supercontinuum laser source (emission spectrum spanning from 1.1 {\mu}m to 4.4 {\mu}m). Capabilities of the in-situ correlative measurements are experimentally demonstrated by obtaining complex multidimensional material data, comprising morphological and chemical information, from a multi-layered composite ceramic-polymer specimen.