Numerical tools for the characterization of microelectromechanical systems by digital holographic microscopy

Digital holography (DH) in microscopy became an important interferometric tool in optical metrology since when the camera sensors have reached a higher pixel number with smaller size and high-speed computers can process the acquired images. This allowed the investigation of engineered surfaces on microscale such as the MEMS. In the DH numerical tools perform the reconstruction of the wavefield. This offers the possibility to retrieve not only the intensity of the acquired wavefield but also the phase distribution. This review describes the principles of DH and shows the most important numerical tools discovered and applied to date in the field of the MEMS. Both the static and the dynamic regime can be analysed by means of DH. Whereas the first one is mostly related to the characterization after the fabrication process while the second is a useful tool to characterize the actuation of the MEMS