Quantitative phase-contrast microscopy

[1][2] Translucent objects, like a living human cell, absorb and scatter small amounts of light.

This makes translucent objects much easier to observe in ordinary light microscopes.

Common to these methods is that an interference pattern (hologram) is recorded by a digital image sensor.

From the recorded interference pattern, the intensity and the phase shift image is numerically created by a computer algorithm.

[4] Quantitative phase contrast microscopy is primarily used to observed unstained living cells.

Figure 1 : In this phase shift image of cells in culture, the height and color of an image point correspond to the measured phase shift. The phase shift induced by an object in an image point depends only on the object thickness and the relative refractive index of the object in the image point. The volume of an object can therefore be determined from a phase shift image when the difference in refractive index between the object and the surrounding media is known. [ 3 ]