  High temporal stability is the primary requirement of any quantitative phase
microscope (QPM) systems for the early stage detection of various human related
diseases. The high temporal stability of the system provides accurate
measurement of membrane fluctuations of the biological cells, which can be good
indicator of various diseases. We developed a single element highly stable
common-path QPM system to obtain temporally stable holograms of the biological
specimens. With the proposed system, the temporal stability is obtained ~ 15
mrad without using any vibration isolation table. The capability of the
proposed system is demonstrated on USAF resolution chart, polystyrene spheres
(dia. 4.5 micron) and human red blood cells (RBCs). The membrane fluctuation of
healthy human RBCs is further successfully measured and found to be equal to 63
nm. Contrary to its counterparts, present system offers energy efficient, cost
effective and simple way of generating object and reference beam for the
development of common-path QPM.
