Multimodal mid-infrared optical coherence tomography and spectroscopy for non-destructive testing and art diagnosis

Novel types of supercontinuum sources radiating in the infrared (IR) spectral region provide ultra-broadband spectral coverage and maintain distinctive laser-like properties of emission such as brightness, spatial coherence and high power. Being a perfectly suitable light source for mid-infrared optical coherence tomography (OCT) and spectroscopy, supercontinuum sources initiated a significant amount of recent developments in these fields and promise to be a gamechanging factor in the nearest future. In this paper, we exhibit a simple, optimized and relatively cost-effective system operating in near and mid-infrared ranges and combining OCT and co-registered IR spectroscopy. The performance of the OCT modality of the setup is evaluated with respect to the sensitivity and roll-off. Due to reduced scattering inherited with the new spectral window, we achieve the enhancement in the penetration depth in artificial paintings, ceramics and pottery. Furthermore, the hyperspectral data is used to supplement structural information and access to the chemical composition of the sample. The gained results reveal the potential of the multimodal system for non-destructive testing, art and cultural objects diagnosis.