Fig. 4: Examples of the four primary holographic imaging model.

Those configurations are corresponding to the fundamental methods in Fig. 3. Only principles are shown here, and various variable experimental devices are produced based on them. a Phase-shifting holography: MZ interferometric example uses the interference between light beams passing through a sample and a reference to generate an interferogram. The reference field is in-line with the imaging field, and four phase shifting are considered phase reconstruction. MO: microscopic objective. b Off-axis holography: MZ interferometric example records the interference between an object wave and a reference wave, and the reference field is tilted to create spatial modulation. c Phase retrieval: non-interferometric imaging method that computationally reconstruct the phase shift from a sequence of intensity images taken under varying conditions. d Sideband modulation holography: A band-limited object wave with an upper half k-space is recorded by the camera with intensity-only, and the phase image is directly retrieved from an intensity image through the analytic expression