Speckle-based phase retrieval applied to 3D microscopy

Nowadays Digital holographic microscopy (DHM) is used for three dimensional imaging of micro-objects. But DHM is a technique which requires the interference between the object beam and a known background, known as the reference beam. The two-beam nature of this makes it prone to external vibrations as well as a tedious adjustment of beam ratios to achieve high fringe contrast. Iterative phase retrieval techniques reconstruct the wavefront from the intensity sampled at several axial planes. This method is an attractive alternative to digital holographic methods, mainly because it is a single beam technique. The wavefront reconstruction is achieved by using the sampled intensity matrices in an appropriate diffraction integral. Angular spectrum propagation approach applied to scalar diffraction theory is used for propagating the wavefront between sampling planes. Here an overview of phase retrieval technique from multiple intensity sampling applied to 3D microscopy is provided.