Restoration of the complex amplitude of a phase object in microscopy by phase modulation interferometry

Observations of phase objects with a microscope generally involve interferometric methods. However, visual or photometric analysis of the interferogram interprets in the same way the information corresponding to the advance and retardation of the wave front transmitted or reflected by an object. Hence, no information about the direction of relief of the object is obtained. An experimental process is described here that is capable of restoring both sign and magnitude of the phase throughout the field. This method, based on modulation interferometry using a microscope and a scanning device, provides the user with different information about the object, such as a display of an intensity image of the interference pattern and its photometric analysis as well as the equal phase contours inside the scanned area, a display of the complex amplitude components and-extending the use of the instrument to the phase measurement technique to complete the data-measurement of the phase for an array of points in the object area.