Depth-resolved multimodal imaging: Wavelength Modulated Spatially Offset Raman Spectroscopy with Optical Coherence Tomography

Mingzhou Chen, Josep Mas, Lindsay H. Forbes, Melissa R. Andrews, and Kishan Dholakia

Journal of Biophotonics, 10.1002/jbio.201700129 (2017)

doi: 10.1002/jbio.201700129

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 capable of detecting both Raman and OCT signals for pharmaceutical particles embedded in turbid media and revealing the white matter at depth within a 0.6mm thick brain tissue layer. This depth resolved label-free multimodal approach is a powerful route to analyze complex biomedical samples.