Epi-mode tomographic quantitative phase imaging in thick scattering samples

Quantitative phase imaging (QPI) is an important tool in biomedicine that yields label-free access to cellular and subcellular structures with nanometer-scale sensitivity. However, implementation of QPI involves a transmission-based geometry and requires thin samples, severely hindering its overall utility in biomedicine. Here we describe our recently developed method, quantitative oblique back illumination microscopy (qOBM), which overcomes this significant limitation and achieves epi-mode, tomographic, quantitative phase imaging in thick samples, including intact thick tissues. Here we describe the method in detail, show validation experiments and results from thick scattering samples.