Quantitative phase imaging in turbid media by coherence controlled holographic microscopy

Quantitative phase imaging (QPI) became an important technique for label-free biomedical imaging suitable particularly for observation of live cell and dry-mass profiling. Extension of this technique to objects immersed in turbid medium is highly desirable with respect to the need of non-invasive observation of live cells in real 3D environments. Coherence-controlled holographic microscopy is capable of QPI through turbid media owing to coherence gating induced in transmitted-light geometry by low spatial coherence of illumination. Using this approach, QPI of object in turbid medium can be formed both by ballistic and multiply scattered photons. Moreover, the particular QPIs formed by ballistic and scattered photons can be superimposed thus yielding synthetic QPI of substantially improved image quality. We support the theoretical reasoning of the effect by experimental data.