Depth-resolved multimodal imaging : wavelength modulated spatially offset Raman spectroscopy with optical coherence tomography

Abstract

A major challenge in biophotonics is multimodal imaging to obtain both morphological and molecular information at depth. We demonstrate a hybrid approach integrating optical coherence tomography (OCT) with wavelength modulated spatially offset Raman spectroscopy (WM-SORS). With depth co-localization obtained from the OCT, we can penetrate 1.2mm deep into the strong scattering media (lard) to acquire up to a 14-fold enhancement of a Raman signal from a hidden target (Polystyrene) with a spatial offset. Our approach is also capable of detecting both Raman and OCT signals for pharmaceutical particles embedded in turbid media and revealing the white matter within a brain tissue layer. This depth resolved label-free multimodal approach is a powerful route to analyze complex biomedical samples.