Ultrahigh resolution spectral-domain optical coherence tomography using the 1000-1600 nm spectral band

Ultrahigh resolution optical coherence tomography (UHR-OCT) can image micro-scopic features that are not visible with the standard OCT resolution of 5-15 mu m. In previous studies, high-speed UHR-OCT has been accomplished within the visible (VIS) and near-infrared (NIR-I) spectral ranges, specifically within 550-950 nm. Here, we present a spectral domain UHR-OCT system operating in a short-wavelength infrared (SWIR) range from 1000 to 1600 nm using a supercontinuum light source and an InGaAs-based spectrometer. We obtained an axial resolution of 2.6 mu m in air, the highest ever recorded in the SWIR window to our knowledge, with deeper penetration into tissues than VIS or NIR-I light. We demonstrate imaging of conduction fibers of the left bundle branch in freshly excised porcine hearts. These results suggest a potential for deep-penetration, ultrahigh resolution OCT in intraoperative applications. (c) 2022 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement