What's digital holography?

 The following figure shows the experimental configuration for digital hologram recording. The light emitted from the laser is divided by a half mirror into two beams. One of them reflected by a mirror for the reference beam and the other illuminates the object for the object beam. Then, the plane reference wave and the object wave are interfering at the surface of a CCD. The resulting hologram is electronically recorded and stored. Because the reconstructed wave field, given by numerical hologram reconstruction, is a complex function, both the intensity as well as the phase can be calculated. Using this process, we can measure shapes, deformations and movements, of the objects.

Fig. 1 Setup of digital holography.

Fig. 2 Reconstruction of the digital hologram.