Abstract
A microscopy technique, spatial-domain low-coherence quantitative phase microscopy (SL-QPM) is proposed for speckle-free, quantitative phase imaging of subcellular structures with subnanometer sensitivity. We quantified, for the first time to our knowledge, the refractive index of the cell nuclei on original unmodified histology specimens. We demonstrate that the refractive index of cell nucleus is highly sensitive in detecting cancer, especially in histologically normal-appearing cells from cancer patients. Because this technique is sensitive and does not require special sample processing, it can be disseminated to all clinical settings.