Digital holographic microscopy (DHM) is one of the most effective techniques used for quantitative phase imaging of cells. Here we present a compact, easy to implement, portable, and very stable DHM setup employing a self-referencing Lloyd's mirror configuration. The microscope is constructed using a diode laser source and a CMOS sensor, making it cost effective. The reconstruction of recorded holograms yields the amplitude and phase information of the object. The temporal stability of the presented technique was found to be around 0.9 nm without any vibration compensation, which makes it ideal for studying cell profile changes. This aspect of the technique is demonstrated by studying membrane fluctuations of red blood cells.
Shape and deformation measurement of diffusely reflecting 3D objects are very important in many application areas, including quality control, nondestructive testing, and design. When rough objects are exposed to coherent beams, the scattered light produces speckle fields. A method to measure the shape and deformation of 3D objects from the sequential intensity measurements of volume speckle field and phase retrieval based on angular-spectrum propagation technique is described here. The shape of a convex spherical surface was measured directly from the calculated phase map, and micrometer-sized deformation induced on a metal sheet was obtained upon subtraction of the phase, corresponding to unloaded and loaded states. Results from computer simulations confirm the experiments.
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