Cells and Holograms – Holograms and Digital Holographic Microscopy as a Tool to Study the Morphology of Living Cells

Digital holographic microscopy (DHM) is an emerging high-resolution imaging technique that offers real-time imaging and quantitative measurements of physiological parameters without any staining or labeling of cells. The first DHM images of living cells were obtained 8-10 years ago [1, 2]. Analysis of human hepatocytes showed that DHM was a versatile tool for in vivo cell analysis by using quantitative amplitude and phase-contrast imaging with very high resolution [1]. Another study showed that the quantitative distribution of the opti‐ cal path length created by transparent specimens contained information concerning both morphology and refractive index of the observed mouse cortical neurons [2]. This could on‐ ly be measured by DHM and not by phase contrast and Nomarski’s differential interference contrast (DIC) microscopy. In addition, the high sensitivity of these phase-shift measure‐ ments enables sub-wavelength axial accuracy, offering attractive possibilities for the visuali‐ zation of cellular dynamics.